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My Ode to Fast Glass

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stevo23 said:
stevo23 wrote:
stevo23 said:
ultimitsu wrote:
stevo23 said:
stevo23 wrote:
stevo23 said:
MediaArchivist wrote:

It would appear from the comments that I am a ludicrous romantic, at best; or a boorish snob, at worst. Fair enough.
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Ha ha. According to a "scientist" at DXO, your camera didn't get any more light just because you used a fast lens and your ability to photograph in the dark is purely the result of it secretly raising it's ISO to fool you into thinking your lens is doing you some good.
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And yes, secret ISO boost is used to pretend that no light was lost.
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How do we know this? I'd love to find out more. I think, personally, that it would be somewhat of a conspiracy.
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you can do this in several different ways.

the best way is to use a fully manual F1.4 or F1.2 lens from another mount, and mounted using a dumb adaptor so your camera does not know what lens is attached. shoot one shot at F1.4 then another at F2.8 with 4 times the shutter time. The F1.4 image should be considerably darker. Thus proving light is not fully utilised at F1.4

But if you only have native Canon F1.4 lenses (and a body), from memnory you can twist the lens a bit so the metal pins do not join, the camera will not know the aperture of the lens, tak a shot, then compare to a shot where lens is fully engaged. I do not have a Canon body with me so I cannot test this out to confirm.

The last method is quite simple, shoot at the maximum ISO and F1.4, then another shot at same ISO and F2.8 but 4 times the shutter time, you should see the first shooting having visibly more noise than the second shot, because its ISO is actually half a stop higher.
 
bobn2 said:
bobn2 wrote:
bobn2 said:
EinsteinsGhost wrote:
bobn2 said:
bobn2 wrote:

It is what it says it is, it is a brightness value, B from the obsolescent APEX system for exposure management. It is an alternative way of expressing the scene luminance. So, it is what the meter measured in the first place. It's relationship to the cameras metering decisions is dictated by the exposure that you told the metering system to aim for in the first place.
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Correct. Except for the fact that, you're basically doing that every time you're pointing your camera to capture an image.
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I'm basically doing what to capture an image? Quantifying the amount of light reflected from each part of the scene? Yes. But there are many different measures of the amount of light coming from the scene, and the one that an exposure meter gives is not ever so useful for constructing photographs. Well, I suppose that you could get a huge sheet of graph paper and mark the EV values in each pixel on it, but it will take a lot of work for a viewer to make out what the scene is. So better, we could translate each of those EV values into a shade of grey, but then we might wonder, why didn't we do that in the first place, and forget all the nonsense of behaving like a light meter does.
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I can't tell. I'm curious to see it in practice because talk is cheap.
bobn2 said:
bobn2 said:
bobn2 said:
Why do you have this obsession with light meters? We're thinking about taking pictures here, not going around measuring the light. A light meter is simply a tool to assist photography, it isn't the thing that takes the picture. So what matters is how a camera works, not how a light meter works.
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Aah, so now you want to avoid having a discussion on metering because your argument falls flat on the ideas you have been believing in for quite some time (obviously).
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No, I want to avoid having a discussion about irrelevancies. We are talking about how cameras work, not how light meters work.
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Why are light meters used? Does your camera not have one?
bobn2 said:
bobn2 said:
BTW, your camera works like a light meter. But you don't want to hear that, right?
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Because it is not true. True is that both instruments measure luminance. There the resemblance ends. And the equivalence that you wish to assert is far beyond that divergence. What you try to assert is that 'exposure' measured by way of ISO and EV is fundamental to photography. Well, it isn't. There are many units you could use for exposure as well as the aforementioned ISO/EV or the APEX brightness units, such as stilb hours, foot-lambert centuries or lux seconds (which is what you;d use under the SI system). None of those units is 'fundamental'. What is fundamental is that exposure is the illuminance at the image plane integrated over the exposure time. The exposure meter becomes an exposure meter by measuring that and expressing it in units familiar (but not fundamental) to photographers. A camera samples that, producing and array on measured illuminance/time values (also sorted according to spectral distribution) which it stores as a set of arbitrarily scaled values in a raw file. Those values may be used to produce and output image with a desired distribution of tonal values (remembering that a tonal value is not the same thing as 'exposure'). What the ISO exposure index does is map exposures to tonal values - the ISO understand both what exposure is and what exposure index is. You seem from what you post to understand neither.
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Cut the crap and tell me how you compose and set up your exposure. It would help if you posted couple of samples in different modes.

And also, if you care for Auto ISO. If you do, why?
bobn2 said:
bobn2 said:
bobn2 said:
bobn2 said:
bobn2 said:
bobn2 said:
bobn2 said:
bobn2 said:
As for sharpness, the m4/3 should have a slight edge wide open but reach diffraction limits sooner.
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Well, the term 'fast' to describe a lens arises because a 'fast' lens allows you to set a faster shutter speed than a 'slow' lens. So what stops you setting as fast a shutter speed as you like? Ultimately, the quality of the output that you will get. Unless we actually want motion blur, why don't we shoot at 1/8000 all the time? Because we know that if we do we'll get a very noisy result unless the light is bright.
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I am unsure as to how your response relates in any way to my point.
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The discussion is about what makes a 'fast' lens. What makes a 'fast' lens is how short a shutter speed you can set, in a given light for some given threshold of image quality (which is always a personal thing)
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And that had nothing to do with my point. And your point adds no value anyway.
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But it does happen to be the etymology of 'fast' with respect to lenses. If you don't want to go with that derivation of the word, then I'd suggest going with something other than 'fast' like 'same-effect-on-exposure'. I admit that's a bit long, but it's more accurate than 'fast'.
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No, it has nothing to do with the etymology of fast or whatever. The point was on diffraction limits per sensor size.
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Well, with as much obfuscation as goes on in your posts, it's quite easy to lose track of where the dicussion has passed. This exchange started with your intervention after my replay to Steen Bay as follows:
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You responded to me and my argument with a non-sense, which you're now dancing around. Take it, or leave it.
bobn2 said:
bobn2 said:
Steen Bay wrote:
bobn2 said:
I'd say that f/1.8 is pretty fast, regardless of the format. Some would probably say that 50/1.8 on FF is faster than 25/1.8 on mFT, but the way I see it, then they are equally fast.
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So you are saying that 50/1.8 on FF and 25/1.8 on mFT with the same shutter speed will give the same quality result?

Or are you saying that a 50/1.8 projects the same amount of light onto a FF sensor as does a 25/1.8 project on a mFT sensor?
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So, it really is about the meaning of 'fast'. When discussion meaning, etymology is a sensible way to look at things.
bobn2 said:
bobn2 said:
bobn2 said:
bobn2 said:
Exactly, you have some minimum shutter speed that you feel that you will use, depending on the subject type (and also typically the lens you are using). What determines whether you feel that you can get away with that shutter speed?
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Experience.
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Care to distill the decision making process behind 'experience'. 'Experience' tells me not to go round corners too fast on my bike, but the decision making process behind that experience is the speed I can go without falling off. Otherwise experience would suggest I go faster. So why isn't experience letting you set a faster shutter speed?
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If you have taken more than 1 image in your life you have some experience. And when you have quite a bit more than that, you begin to appreciate the limits of usefulness of it instead of operating like a mindless shooter, failing to recognize limits. Now tell me why YOU would go around shooting an NBA game at 1/4000s?
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You fail to understand the separation between experience and learning from experience. You may have experience, but you can (and clearly have) fail to learn from it. The when I asked 'What determines whether you feel that you can get away with that shutter speed?', 'experience' was a pretty silly answer. The nub of the question is what you have learned from experience - and what I leaned from experience is that if I use too low an exposure through using a very short shutter speed I got more noise than was acceptable to me. What I also learned from experience was that the exposure that I needed to get the same noise varied with frame size (and quite a few other things). Optical theory supports my experience.
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I take it that you have no experience shooting at an NBA game? If you do, what settings did you use? And why? Knowing what and why YOU do something might help you understand why others might.
bobn2 said:
bobn2 said:
bobn2 said:
bobn2 said:
But here's the more interesting point: I was getting 1/500s for shutter speed at f/2 (ISO 400), but 1/640s at f/2.8 (ISO 800).
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Then there's something wrong with your meter or metering technique or the f/2 setting isn't a stop faster than f/2.8 on your camera and lens (which rather undermines the idea that f/2=f/2=f/2). In any case, which one do you want to use, 1/500 or 1/640?
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Have you never used Shutter Priority, or Aperture Priority, or Manual Mode (especially with Auto ISO) that you come up with this argument? It is the same venue, same camera body, but different FoV. The "meter" is the same. There could be a difference in metering due to the FoV available for metering.
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OK, so it's a trick question. You aren't shooting the same shot. Pretty useless piece of argument, really.
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Every image has a message, when coupled with information within. If you can't make head and tail out of it, the problem is with you. And when you don't, move on, rather than shed tears about it. Ask, or move on.
bobn2 said:
bobn2 said:
But yes, that is exactly the point that I was wondering. Now you know better about metering differences?
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I haven't leaned anything about 'metering differences' from this discussion, but then I already knew considerably more than the person I'm conversing with, so its not surprising. So far it seems that you don't know enough to know what you don't know. Your bravura doesn't hide your ignorance, I'm afraid.
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It may be about denial. Or, worse, sheer ignorance coupled with some kind of hatred to learn or at least understand the points being presented.
 
Great Bustard said:
Great Bustard wrote:

Changing the aperture for a given scene luminance and shutter speed changes the exposure. Sad that this is not obvious to you, especially after it's been explained multiple times.
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But changing ISO does not? What the heck you people are smoking? I do take it that you believe cameras can do without ISO setting at all, while plenty of idiots demand "Auto ISO" even in manual settings.
Great Bustard said:
Great Bustard said:
Great Bustard said:
Great Bustard said:
The ISO-less concept (which my previous examples actually used) is a different issue altogether for which you must address the sensitivity aspect in post processing (RAW).
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So when I asked you to define "sensitivity" above and you said:

What you get by changing ISO in your camera.

How does that connect with your use of the word "sensitivity" here? Are you trying to say that if you shoot a photo that is two stops "too dark" that you have to push the RAW conversion two stops to get the desired brightness? Does the word "duh" come to mind?
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2-stops "under-exposed" would be the correct way. Duh!
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Again, the exposure is fixed by the scene luminance, t-stop (usually the f-ratio is close enough), and shutter speed. The ISO setting simply changes the brightness of the LCD playback and/or OOC jpg.
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So, the only reason you'd use ISO setting in your camera would be for OOC JPEG or for LCD reviews. Otherwise, you might as well get rid of any notion of ISO (and film sensitivity). Right? So, why not post couple of examples that demonstrate this fine approach of yours? It can make for an excellent argument against those who whine and cry all day long about IQ issues at higher ISO (which would include YOU).
Great Bustard said:
So, for a given scene, f/2.8 1/100 ISO 100 and f/2.8 1/100 ISO 1600 have the same exposure, but the ISO 1600 photo is 16x (4 stops) brighter. The reason we would shoot ISO 1600 rather than ISO 100, then, is to get the proper LCD playback and/or OOC jpg brightness, as well as less noise for photos taken with cameras that have non-ISOless sensors .
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Can you post a pair of images, 4-stops apart, which is not OOC JPG?
Great Bustard said:
Great Bustard said:
Great Bustard said:
Great Bustard said:
Great Bustard said:
Many use the ISO control to indirectly set the shutter speed, aperture, and/or flash power, but, make no mistake, it is the change in shutter speed, aperture, and/or flash power that results in a change to the exposure, not the ISO setting.
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Whats funny is that if we were to have a discussion on Auto ISO in manual mode, you'd be singing a different tune.
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I'd be singing the same tune. Let's say that I'm in manual mode (M) at f/2.8 1/100 with Auto ISO set. If the ISO changes, it simply reflects that the scene luminance has changed, exactly as I have said.

Does it hurt, yet?
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But, according to you, ISO has no effect on exposure.
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It does not. Exposure is determined *entirely* by the scene luminance, t-stop (usually closely approximated by the f-ratio), and shutter speed -- a simple fact that you refuse to understand.
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It does. You're either in denial, or ignorant of the fact. When was the last time you adjusted ISO (or used Auto ISO), for anything but chimping? And why does camera need ISO for OOC JPEGs? You've not thought this through?
 
Narrow DOF rocks. Beautiful bokeh rocks. And for wide field astrophotography, aperture does matter because everything you want (stars, Milky Way, galaxies) is faint. I use my f/1.4 lens at f/2 or f/2.2 to eliminate coma and get corner to corner sharpness.
 
Number2 said:
Number2 wrote:
Number2 said:
EinsteinsGhost wrote:
Number2 said:
Great Bustard wrote:And the aperture you set to get the desired effect will change the exposure for a given shutter speed.
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May, or may not. (Think about it).
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Instead of being blunt (put put it politely) in your conversation you might want to learn from it instead.

Exposure is of nothing but the density of light hitting the sensor and is dictated by three parameters:
  1. ambient light
  2. aperture value
  3. shutter value
If any of these changes, exposure changes.

As GB said, changing the aperture to get a desired effect will indeed change the exposure for a given shutter speed. He is right, you're wrong.
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That is your opinion, and I guess understanding of the subject. But for me, an ingredient is missing. That ingredient, I suspect, you need, just don't recognize. But, let us use your argument, completely disregarding sensitivity (boosted or otherwise) of the media the image is to be captured since you don't consider it a part of the equation.

You're shooting in good light conditions, exposure value of 10. You have selected f/5.6. What shutter speed would you use if using manual exposure (or would the camera evaluate if using aperture priority)? Why?
 
You don't always have full control over your background, particularly if you are a wildlife photographer. Shallow DOF is a tool to eliminate distracting background elements and get the viewer to look first at your main subject.
 
ultimitsu said:
ultimitsu wrote:
ultimitsu said:
EinsteinsGhost wrote:
ultimitsu said:
ultimitsu wrote:
ultimitsu said:
EinsteinsGhost wrote:
ultimitsu said:
Now let me ask you a question. if you set you camera to M, keep shutter speed and aperture the same, change ISO from 100 to 200, do you think exposure has changed?
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Yes, by 1 stop.
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I think this explains it all. you have been told many times why ISO amplfication is not part of exposure. GB even gave you the link to an excellent article that explains the difference between brightness and exposure.
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Then you've missed the point. Are you sure you will return with identically exposed images if you captured a scene at different ISO settings?
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Identically exposed? yes, Identical image? no. Images are not identical because they have different brightness.
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In other words, you will get result 1-stop underexposed. Hence my earlier response (now in bold). I somehow suspect that you do use ISO settings in your camera. May I ask why you do?
ultimitsu said:
Just like when you process the same RAW into two images, one with colour and one black and white, Are they identical? of course not, but do they have the same exposure? yes. ISO amplification is the same deal. it is a process executed after the exposure was completed and image was captured.
ultimitsu said:
ultimitsu said:
But what do you do? You continue to actively resist learning, in fact you defiantly proclaimed "stop reading". You would spend hours and hours typing and repeating the same non-sense but would not spend just 30 minutes to read that article.
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Excuse me for not joining this collective. Now, invest less of your time whining about it, and more on making arguments, preferably demonstrated. That will go a long way.
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By "this collective", in the context of this point, seems to refer to people who read and learn.
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Or, believe that they have learnt. And they might have, except that it isn't really helping make a point, or illustrate any of the claims they are making.
ultimitsu said:
ultimitsu said:
ultimitsu said:
In my view the only explanation to all this is that you are deliberately and maliciously pretending to be dumb and acting non-responsively.
ultimitsu said:
When the only change you're making is ISO, and observing shutter speed change with it, don't turn around and claim there is no relationship between the two.
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You saw a change in SS only because your camera was actively metering the scene. Your camera does not set ss in abstract, it sets ss to produce a final image with consistent brightness. Because you have changed ISO which increases brightness, to ensure final image has the same brightness your camera had to reduce exposure, and it did that by increasing shutter speed.
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I prefer proper "exposure" as the term.
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Indeed, the use of the term exposure should be confined to its proper meaning.
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And I suspect the collective uses them interchangeably, so I try to ensure just that.
ultimitsu said:
ultimitsu said:
Ever shoot ISO-less? I've, and the two samples I posted earlier were taken with that. So, trust me, I know what to look for, and tell you to look for.
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You mean the basketball shots? what exactly are you trying to say about them in the context of "iso-less"
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Gladly. Have you ever shot at an NBA arena? If you have, provide your typical settings. We will go from there and compare to mine.
 
EinsteinsGhost said:
EinsteinsGhost wrote:
EinsteinsGhost said:
Great Bustard wrote:

Changing the aperture for a given scene luminance and shutter speed changes the exposure. Sad that this is not obvious to you, especially after it's been explained multiple times.
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But changing ISO does not? What the heck you people are smoking? I do take it that you believe cameras can do without ISO setting at all, while plenty of idiots demand "Auto ISO" even in manual settings.
EinsteinsGhost said:
EinsteinsGhost said:
EinsteinsGhost said:
EinsteinsGhost said:
The ISO-less concept (which my previous examples actually used) is a different issue altogether for which you must address the sensitivity aspect in post processing (RAW).
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So when I asked you to define "sensitivity" above and you said:

What you get by changing ISO in your camera.

How does that connect with your use of the word "sensitivity" here? Are you trying to say that if you shoot a photo that is two stops "too dark" that you have to push the RAW conversion two stops to get the desired brightness? Does the word "duh" come to mind?
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2-stops "under-exposed" would be the correct way. Duh!
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Again, the exposure is fixed by the scene luminance, t-stop (usually the f-ratio is close enough), and shutter speed. The ISO setting simply changes the brightness of the LCD playback and/or OOC jpg.
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So, the only reason you'd use ISO setting in your camera would be for OOC JPEG or for LCD reviews.
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Well, the LCD playback is a big deal for me. However, since I shoot Canon, which does not use ISOless sensors, there's also this:

http://www.dpreview.com/forums/post/52189226

You change the ISO to change the brightness of the LCD playback and/or OOC jpg. Also, with an ISOless sensor (such as Canon's sensors), the higher ISOs result in less noise than a lower ISO pushed to a given brightness. For example, ISO 1600 is less noisy than ISO 100 pushed four stops for a given exposure.
EinsteinsGhost said:
Otherwise, you might as well get rid of any notion of ISO (and film sensitivity). Right?
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For cameras with ISOless sensors, all they need is an ISOless UI, and, yes, you can do away with ISO completely. Also, when shooting in manual mode (M) with Auto ISO and user definable safety shifts, once again, you don't need ISO.
EinsteinsGhost said:
So, why not post couple of examples that demonstrate this fine approach of yours? It can make for an excellent argument against those who whine and cry all day long about IQ issues at higher ISO (which would include YOU).
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See the links in the third and forth paragraphs:

http://www.josephjamesphotography.com/equivalence/#iso

A common myth is that higher ISOs cause more noise. The effect of the ISO setting is to indirectly changes the f-ratio, shutter speed, and/or flash power depending on the metering mode we are in, as well as adjust the brightness of the LCD playback and/or OOC jpg. Higher ISOs result in more narrow apertures, faster shutter speeds, and/or less flash power than lower ISOs for a given scene luminance, which results in less light falling on the sensor, and thus more photon noise. In other words, it is the lesser amount of light falling on the sensor at higher ISOs than lower ISOs that results in greater noise at higher ISOs, not the higher ISO setting, per se.

Unlike film, the sensitivity of the sensor is fixed -- that is, the ISO setting does not affect the efficiency of the sensor. However, for sensors with noisy ADCs (Analog to Digital Conversion units), higher ISO settings result in less read noise than lower ISO settings. For example, the read noise for the Canon 5D3 at base ISO (100) is 33.1 electrons, drops to 18.2 electrons at ISO 200, and continues to drop until it finally levels off at around 3 electrons at ISO 3200. On the other hand, some sensors, like the Sony Exmor sensor in the Nikon D7000 and D800, have the same read noise throughout the entire ISO range. These types of sensors are referred to as "ISOless", although it's worth noting that even "non-ISOless" sensors usually become ISOless after some point in the ISO range.

For a camera with an ISOless sensor, the only reason for using higher ISOs is operational convenience, as no cameras currently have an ISOless UI (user interface). For example, let's say a photo of a scene at f/2.8 1/100 ISO 800 resulted in the desired output brightness. If we instead took the photo at f/2.8 1/100 ISO 100 and pushed the file three stops, in a RAW conversion, the resulting files would be the same, whereas if we did the same with a camera using an non-ISOless sensor, the ISO 800 photo would be less noisy than the ISO 100 photo (see here and here for demonstrations).

The disadvantage, then, of shooting at higher ISOs with a camera using an ISOless sensor is that the recorded file may very well oversaturate (blow) portions of the scene since portions well within the saturation limits of the pixel will be pushed outside the bit depth of the recorded file, whereas using the appropriate tone curve in the processing of a photo taken at base ISO could retain much more of the highlights (see here for a demonstration). However, since neither the output jpg brightness nor the LCD playback are tied to the camera's meter, operationally, using a camera with an ISOless sensor in an ISOless manner is very inconvenient.
EinsteinsGhost said:
EinsteinsGhost said:
So, for a given scene, f/2.8 1/100 ISO 100 and f/2.8 1/100 ISO 1600 have the same exposure, but the ISO 1600 photo is 16x (4 stops) brighter. The reason we would shoot ISO 1600 rather than ISO 100, then, is to get the proper LCD playback and/or OOC jpg brightness, as well as less noise for photos taken with cameras that have non-ISOless sensors .
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Can you post a pair of images, 4-stops apart, which is not OOC JPG?
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Are you seriously asking that? I mean, are you really asking me to post a photo taken at f/2.8 1/100 ISO 1600 and a photo of the same scene taken at f/2.8 1/100 ISO 100 and pushed four stops in the conversion?

Well, as I said, the differences will be in terms of noise. For photos taken with an ISOless sensor, there will be no difference. For photos taken with a non-ISOless sensor, the ISO 100 photo will be more noisy.

In neither case, however, does ISO figure into exposure.

EinsteinsGhost said:
EinsteinsGhost said:
EinsteinsGhost said:
EinsteinsGhost said:
EinsteinsGhost said:
EinsteinsGhost said:
Many use the ISO control to indirectly set the shutter speed, aperture, and/or flash power, but, make no mistake, it is the change in shutter speed, aperture, and/or flash power that results in a change to the exposure, not the ISO setting.
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Whats funny is that if we were to have a discussion on Auto ISO in manual mode, you'd be singing a different tune.
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I'd be singing the same tune. Let's say that I'm in manual mode (M) at f/2.8 1/100 with Auto ISO set. If the ISO changes, it simply reflects that the scene luminance has changed, exactly as I have said.

Does it hurt, yet?
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But, according to you, ISO has no effect on exposure.
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It does not. Exposure is determined *entirely* by the scene luminance, t-stop (usually closely approximated by the f-ratio), and shutter speed -- a simple fact that you refuse to understand.
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It does. You're either in denial, or ignorant of the fact.
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You are not in a position to call anyone ignorant. Indeed, your flurry of self=harming posts are an epic testament to that.
EinsteinsGhost said:
When was the last time you adjusted ISO (or used Auto ISO), for anything but chimping?
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Well, I chimp all the time, so I need the LCD playback to show the desired brightness all the time. In addition, as I said, my camera does not sport an ISOless sensor, so I get less noisy photos by using a higher ISO than base ISO and pushing to the desired brightness.

Again, in neither case does ISO figure into exposure.
EinsteinsGhost said:
And why does camera need ISO for OOC JPEGs?
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Are you seriously asking that? Wow. The camera uses the ISO setting to determine the amplification that needs to be applied to the image file for the desired brightness.

However, the camera could just as well tie the LCD playback and OOC jpg brightness to the brightness of a zero meter, but they don't -- they use the ISO setting instead.
EinsteinsGhost said:
You've not thought this through?
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Just a wee bit more than you, apparently.
 
ultimitsu said:
ultimitsu wrote:
ultimitsu said:
stevo23 wrote:
ultimitsu said:
ultimitsu wrote:
ultimitsu said:
stevo23 wrote:
ultimitsu said:
MediaArchivist wrote:

It would appear from the comments that I am a ludicrous romantic, at best; or a boorish snob, at worst. Fair enough.
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Ha ha. According to a "scientist" at DXO, your camera didn't get any more light just because you used a fast lens and your ability to photograph in the dark is purely the result of it secretly raising it's ISO to fool you into thinking your lens is doing you some good.
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And yes, secret ISO boost is used to pretend that no light was lost.
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How do we know this? I'd love to find out more. I think, personally, that it would be somewhat of a conspiracy.
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you can do this in several different ways.

the best way is to use a fully manual F1.4 or F1.2 lens from another mount, and mounted using a dumb adaptor so your camera does not know what lens is attached. shoot one shot at F1.4 then another at F2.8 with 4 times the shutter time. The F1.4 image should be considerably darker. Thus proving light is not fully utilised at F1.4

But if you only have native Canon F1.4 lenses (and a body), from memnory you can twist the lens a bit so the metal pins do not join, the camera will not know the aperture of the lens, tak a shot, then compare to a shot where lens is fully engaged. I do not have a Canon body with me so I cannot test this out to confirm.

The last method is quite simple, shoot at the maximum ISO and F1.4, then another shot at same ISO and F2.8 but 4 times the shutter time, you should see the first shooting having visibly more noise than the second shot, because its ISO is actually half a stop higher.
Click to expand...
And have you done this to confirm? I don't have an f1.2 lens or even a 1.4 lens to be able to test. But that being said, the benefits aren't just about light gathering and the DXO article seems to miss that. When you can get an f1.4 lens to give you excellent sharpness across the frame at 1.4, you're going to be able to get some nice shallow DOF results even if the ISO is magically boosted to mask the light falloff.

I personally find the idea of "secret ISO boost" to be scandalous to say the least. But I also don't recall anything convincing in DXO's article on the subject overall. It really was baffling to me that it was even worth mentioning.
 
EinsteinsGhost said:
EinsteinsGhost wrote:
EinsteinsGhost said:
Number2 wrote:
EinsteinsGhost said:
EinsteinsGhost wrote:
EinsteinsGhost said:
Great Bustard wrote:And the aperture you set to get the desired effect will change the exposure for a given shutter speed.
Click to expand...
May, or may not. (Think about it).
Click to expand...
Instead of being blunt (put put it politely) in your conversation you might want to learn from it instead.

Exposure is of nothing but the density of light hitting the sensor and is dictated by three parameters:
  1. ambient light
  2. aperture value
  3. shutter value
If any of these changes, exposure changes.

As GB said, changing the aperture to get a desired effect will indeed change the exposure for a given shutter speed. He is right, you're wrong.
Click to expand...
That is your opinion...
Click to expand...
It is a fact, not opinion.
EinsteinsGhost said:
...and I guess understanding of the subject.
Click to expand...
His correct understanding.
EinsteinsGhost said:
But for me, an ingredient is missing. That ingredient, I suspect, you need, just don't recognize.
Click to expand...
Your posts indicate that you are missing more than a few ingredients.
EinsteinsGhost said:
But, let us use your argument, completely disregarding sensitivity (boosted or otherwise) of the media the image is to be captured since you don't consider it a part of the equation.
Click to expand...
The "sensitivity" of a digital sensor is fixed, except inasmuch as read noise lowers for higher ISOs (to a point) with non-ISOless sensors, which means, for example, that ISO 100 pushed four stops will be more noisy than ISO 1600 for a given exposure.
EinsteinsGhost said:
You're shooting in good light conditions, exposure value of 10. You have selected f/5.6. What shutter speed would you use if using manual exposure (or would the camera evaluate if using aperture priority)? Why?
Click to expand...
Clearly, you've selected f/5.6 for DOF and/or sharpness reasons. This is how DOF figures into exposure that you were not able to comprehend over multiple posts above.

Secondly, you a competent photographer chooses the shutter speed based on motion blur and/or camera shake (many use the ISO setting to indirectly change the shutter speed if shooting in aperture priority -- Av -- mode). Alternatively, if there is too much light, we choose a higher shutter speed than is necessary for motion blur / camera shake so as to not oversaturate (blow highlights) in the photo (we'll assume this is automatically dealt with by a shutter speed safety shift).

Lastly, you the competent photographer compromises on aperture and/or shutter speed as necessary to balance with noise. With the current UI, we use the ISO setting as a gauge for noise. With an ISOless UI, the meter would show how many stops you are above or below the recommended exposure, which would give you the exact same information about noise.

In all cases, the ISO setting does not figure into the exposure. The exposure is determined solely by the scene luminance, the t-stop (usually closely approximated by the f-ratio), and the shutter speed. We adjust the ISO solely to get the desired LCD playback / OOC jpg brightness and/or to indirectly alter one of the three parameters of exposure, that is, changing the ISO indirectly changes the aperture, shutter speed, and/or flash power.
 
Great Bustard said:
Great Bustard wrote:
Great Bustard said:
EinsteinsGhost wrote:

So, the only reason you'd use ISO setting in your camera would be for OOC JPEG or for LCD reviews.
Click to expand...
Well, the LCD playback is a big deal for me. However, since I shoot Canon, which does not use ISOless sensors, there's also this:

http://www.dpreview.com/forums/post/52189226

You change the ISO to change the brightness of the LCD playback and/or OOC jpg. Also, with an ISOless sensor (such as Canon's sensors), the higher ISOs result in less noise than a lower ISO pushed to a given brightness. For example, ISO 1600 is less noisy than ISO 100 pushed four stops for a given exposure.
Click to expand...
Let me point at another contradiction again (just I did with your argument on ISO changing exposure but being irrelevant for exposure): See your statements in bold. Your arguments are a mess, really.

Ignoring more of that incoherence which has become your signature, why would shoot ISO-less if all you use ISO for is to review? In fact, shooting ISO-less makes it more difficult to review (a reason I usually stick with 1-2 stops only). If you didn't get this point of mine either, you make the choice to shoot ISO-less so you can keep ISO setting on your camera LOW (not high) which will present you with an underexposed review.
Great Bustard said:
Great Bustard said:
Otherwise, you might as well get rid of any notion of ISO (and film sensitivity). Right?
Click to expand...
For cameras with ISOless sensors, all they need is an ISOless UI, and, yes, you can do away with ISO completely. Also, when shooting in manual mode (M) with Auto ISO and user definable safety shifts, once again, you don't need ISO.
Click to expand...
So, there is no need for Auto ISO, and especially if you don't go chimping around. Perhaps that explains why I am such a big proponent of manual ISO. ;)
Great Bustard said:
Great Bustard said:
So, why not post couple of examples that demonstrate this fine approach of yours? It can make for an excellent argument against those who whine and cry all day long about IQ issues at higher ISO (which would include YOU).
Click to expand...
See the links in the third and forth paragraphs...
Click to expand...
I asked you to demonstrate with couple of examples (see bold), not go parroting with the usual (again).
Great Bustard said:
Are you seriously asking that? I mean, are you really asking me to post a photo taken at f/2.8 1/100 ISO 1600 and a photo of the same scene taken at f/2.8 1/100 ISO 100 and pushed four stops in the conversion?
Click to expand...
Why would you have to push four stops in conversion? And yes, I'm seriously asking you to post a pair of samples. It will lead to a meaningful discussion.
Great Bustard said:
Well, as I said, the differences will be in terms of noise. For photos taken with an ISOless sensor, there will be no difference. For photos taken with a non-ISOless sensor, the ISO 100 photo will be more noisy.
Click to expand...
Don't worry about noise or dynamic range or color depth. I'm strictly working with exposure variables.
Great Bustard said:
Great Bustard said:
It does. You're either in denial, or ignorant of the fact.
Click to expand...
You are not in a position to call anyone ignorant. Indeed, your flurry of self=harming posts are an epic testament to that.
Click to expand...
I didn't assume ignorance on your part, rather denial which is more likely.
Great Bustard said:
Great Bustard said:
When was the last time you adjusted ISO (or used Auto ISO), for anything but chimping?
Click to expand...
Well, I chimp all the time, so I need the LCD playback to show the desired brightness all the time. In addition, as I said, my camera does not sport an ISOless sensor, so I get less noisy photos by using a higher ISO than base ISO and pushing to the desired brightness.

Again, in neither case does ISO figure into exposure.
Click to expand...
Then there should be no need "to push" by the same number of stops you chose to reduce the sensitivity with. When you don't want to have to "push", you actually go begging for ISO.
Great Bustard said:
Great Bustard said:
And why does camera need ISO for OOC JPEGs?
Click to expand...
Are you seriously asking that? Wow. The camera uses the ISO setting to determine the amplification that needs to be applied to the image file for the desired brightness.
Click to expand...
But you keep saying that ISO setting does not affect exposure.
Great Bustard said:
However, the camera could just as well tie the LCD playback and OOC jpg brightness to the brightness of a zero meter, but they don't -- they use the ISO setting instead.
Great Bustard said:
You've not thought this through?
Click to expand...
Just a wee bit more than you, apparently.
Click to expand...
That is the best you can hope.
 
Great Bustard said:
Great Bustard wrote:
Great Bustard said:
EinsteinsGhost wrote:
Great Bustard said:
Number2 wrote:
Great Bustard said:
EinsteinsGhost wrote:
Great Bustard said:
Great Bustard wrote:And the aperture you set to get the desired effect will change the exposure for a given shutter speed.
Click to expand...
May, or may not. (Think about it).
Click to expand...
Instead of being blunt (put put it politely) in your conversation you might want to learn from it instead.

Exposure is of nothing but the density of light hitting the sensor and is dictated by three parameters:
  1. ambient light
  2. aperture value
  3. shutter value
If any of these changes, exposure changes.

As GB said, changing the aperture to get a desired effect will indeed change the exposure for a given shutter speed. He is right, you're wrong.
Click to expand...
That is your opinion...
Click to expand...
It is a fact, not opinion.
Great Bustard said:
...and I guess understanding of the subject.
Click to expand...
His correct understanding.
Great Bustard said:
But for me, an ingredient is missing. That ingredient, I suspect, you need, just don't recognize.
Click to expand...
Your posts indicate that you are missing more than a few ingredients.
Great Bustard said:
But, let us use your argument, completely disregarding sensitivity (boosted or otherwise) of the media the image is to be captured since you don't consider it a part of the equation.
Click to expand...
The "sensitivity" of a digital sensor is fixed, except inasmuch as read noise lowers for higher ISOs (to a point) with non-ISOless sensors, which means, for example, that ISO 100 pushed four stops will be more noisy than ISO 1600 for a given exposure.
Great Bustard said:
You're shooting in good light conditions, exposure value of 10. You have selected f/5.6. What shutter speed would you use if using manual exposure (or would the camera evaluate if using aperture priority)? Why?
Click to expand...
Clearly, you've selected f/5.6 for DOF and/or sharpness reasons. This is how DOF figures into exposure that you were not able to comprehend over multiple posts above.

Secondly, you a competent photographer chooses the shutter speed based on motion blur and/or camera shake (many use the ISO setting to indirectly change the shutter speed if shooting in aperture priority -- Av -- mode). Alternatively, if there is too much light, we choose a higher shutter speed than is necessary for motion blur / camera shake so as to not oversaturate (blow highlights) in the photo (we'll assume this is automatically dealt with by a shutter speed safety shift).

Lastly, you the competent photographer compromises on aperture and/or shutter speed as necessary to balance with noise. With the current UI, we use the ISO setting as a gauge for noise. With an ISOless UI, the meter would show how many stops you are above or below the recommended exposure, which would give you the exact same information about noise.

In all cases, the ISO setting does not figure into the exposure. The exposure is determined solely by the scene luminance, the t-stop (usually closely approximated by the f-ratio), and the shutter speed. We adjust the ISO solely to get the desired LCD playback / OOC jpg brightness and/or to indirectly alter one of the three parameters of exposure, that is, changing the ISO indirectly changes the aperture, shutter speed, and/or flash power.
Click to expand...
You're a prime example of people who think they read, and think that they think. And, that would explain why you went parroting again with non-sense rather than address what is asked (in bold above). If you cannot, don't waste real estate here. You will not be responded to in this sequence if you come back with anything but a direct response to that question.
 
EinsteinsGhost said:
EinsteinsGhost wrote:
EinsteinsGhost said:
Number2 wrote:
EinsteinsGhost said:
EinsteinsGhost wrote:
EinsteinsGhost said:
Great Bustard wrote:And the aperture you set to get the desired effect will change the exposure for a given shutter speed.
Click to expand...
May, or may not. (Think about it).
Click to expand...
Instead of being blunt (put put it politely) in your conversation you might want to learn from it instead.

Exposure is of nothing but the density of light hitting the sensor and is dictated by three parameters:
  1. ambient light
  2. aperture value
  3. shutter value
If any of these changes, exposure changes.

As GB said, changing the aperture to get a desired effect will indeed change the exposure for a given shutter speed. He is right, you're wrong.
Click to expand...
That is your opinion, and I guess understanding of the subject.
Click to expand...
It is in fact the standard defination of exposure in the context of photography.
EinsteinsGhost said:
But for me, an ingredient is missing. That ingredient, I suspect, you need, just don't recognize.
Click to expand...
But then you're no longer talking about exposure but something else. http://en.wikipedia.org/wiki/Exposure_(photography)

EinsteinsGhost said:
But, let us use your argument, completely disregarding sensitivity (boosted or otherwise) of the media the image is to be captured since you don't consider it a part of the equation.
Click to expand...
Sensitivity is not part of exposure. Additionally, for digital cameras, sensitivity is constant - the quantum efficiency of the sensor does not change with any change of settings. For most cameras (especially Canons) the electrical noise may lower a bit if a higher ISO is selected.
EinsteinsGhost said:
You're shooting in good light conditions, exposure value of 10. You have selected f/5.6. What shutter speed would you use if using manual exposure (or would the camera evaluate if using aperture priority)? Why?
Click to expand...
I set both the aperture and shutter speed according to artistic (DOF and motion blur) and technical (shake elimination) needs, regardless of the light conditions - why would I do anything else? I may adjust the ISO if I want to minimise the electronic noise, but there is no real need to do that on my camera. And yes, I shoot in raw only. Almost always I shoot in M-mode. I prefer to control the exposure myself as the camera has a tendency of not filling the sensor capacity enough. Usually ISO 100 even if the sensor capacity does not get filled by the exposure as the camera I use is almost ISOless and there may be some highlights I want to be sure of saving.
 
Number2 said:
Number2 wrote:
Number2 said:
EinsteinsGhost wrote:
Number2 said:
Number2 wrote:
Number2 said:
EinsteinsGhost wrote:
Number2 said:
Great Bustard wrote:And the aperture you set to get the desired effect will change the exposure for a given shutter speed.
Click to expand...
May, or may not. (Think about it).
Click to expand...
Instead of being blunt (put put it politely) in your conversation you might want to learn from it instead.

Exposure is of nothing but the density of light hitting the sensor and is dictated by three parameters:
  1. ambient light
  2. aperture value
  3. shutter value
If any of these changes, exposure changes.

As GB said, changing the aperture to get a desired effect will indeed change the exposure for a given shutter speed. He is right, you're wrong.
Click to expand...
That is your opinion, and I guess understanding of the subject.
Click to expand...
It is in fact the standard defination of exposure in the context of photography.
Number2 said:
But for me, an ingredient is missing. That ingredient, I suspect, you need, just don't recognize.
Click to expand...
But then you're no longer talking about exposure but something else. http://en.wikipedia.org/wiki/Exposure_(photography)
Number2 said:
But, let us use your argument, completely disregarding sensitivity (boosted or otherwise) of the media the image is to be captured since you don't consider it a part of the equation.
Click to expand...
Sensitivity is not part of exposure. Additionally, for digital cameras, sensitivity is constant - the quantum efficiency of the sensor does not change with any change of settings. For most cameras (especially Canons) the electrical noise may lower a bit if a higher ISO is selected.
Click to expand...
Okay, we had already assumed that for now, when I added the following:
Number2 said:
Number2 said:
You're shooting in good light conditions, exposure value of 10. You have selected f/5.6. What shutter speed would you use if using manual exposure (or would the camera evaluate if using aperture priority)? Why?
Click to expand...
I set both the aperture and shutter speed according to artistic (DOF and motion blur) and technical (shake elimination) needs, regardless of the light conditions - why would I do anything else? I may adjust the ISO if I want to minimise the electronic noise, but there is no real need to do that on my camera. And yes, I shoot in raw only. Almost always I shoot in M-mode. I prefer to control the exposure myself as the camera has a tendency of not filling the sensor capacity enough. Usually ISO 100 even if the sensor capacity does not get filled by the exposure as the camera I use is almost ISOless and there may be some highlights I want to be sure of saving.
Click to expand...
You see, we don't want to consider ISO adjustments for this discussion, if you want to have it your way. So, let us not worry about that at all. Instead answer my question (assume shooting at hyper focal distance... so stop worrying about DoF and motion blur too... it will take a LOT of movement under the lighting conditions to even worry about motion blur).

The situation/question is in bold above.
 
NancyP said:
NancyP wrote:

You don't always have full control over your background, particularly if you are a wildlife photographer. Shallow DOF is a tool to eliminate distracting background elements and get the viewer to look first at your main subject.
Click to expand...
 
NancyP said:
NancyP wrote:

Narrow DOF rocks. Beautiful bokeh rocks. And for wide field astrophotography, aperture does matter because everything you want (stars, Milky Way, galaxies) is faint. I use my f/1.4 lens at f/2 or f/2.2 to eliminate coma and get corner to corner sharpness.
Click to expand...
 
EinsteinsGhost said:
EinsteinsGhost wrote:
EinsteinsGhost said:
ultimitsu wrote:
EinsteinsGhost said:
EinsteinsGhost wrote:
EinsteinsGhost said:
ultimitsu wrote:
EinsteinsGhost said:
EinsteinsGhost wrote:
EinsteinsGhost said:
Now let me ask you a question. if you set you camera to M, keep shutter speed and aperture the same, change ISO from 100 to 200, do you think exposure has changed?
Click to expand...
Yes, by 1 stop.
Click to expand...
I think this explains it all. you have been told many times why ISO amplfication is not part of exposure. GB even gave you the link to an excellent article that explains the difference between brightness and exposure.
Click to expand...
Then you've missed the point. Are you sure you will return with identically exposed images if you captured a scene at different ISO settings?
Click to expand...
Identically exposed? yes, Identical image? no. Images are not identical because they have different brightness.
Click to expand...
In other words, you will get result 1-stop underexposed. Hence my earlier response (now in bold). I somehow suspect that you do use ISO settings in your camera. May I ask why you do?
Click to expand...
ISO setting does not influence exposure. ISO infuences either analog or digital (or both) gain to the signal. If the gain is digital, nothing else is done, but every number in the data is adjusted by a factor (of 2 for each doubling of the ISO). Some cameras even treat ISO as metadata only (most or all Sigmas for example).

If you shoot out-of-camera-JPG-images, setting an ISO which causes the camera to create as bright image as one wants to is usually important.

However, if you shoot RAW, and your camera is ISOless or close to it, you can just brighten in the raw converter to your taste.

Now, are you of the false opinion that if I take a picure in raw, and make two JPG versions of it in the raw converter, where one has been pushed to be 1 stop brighter, the exposure of has also changed? What if it is the camera which does the brightening instead of me afterwards? What if I shoot on a camera where ISO in raw files is just metadata?
 
Number2 said:
Number2 wrote:
Number2 said:
EinsteinsGhost wrote:
Number2 said:
ultimitsu wrote:
Number2 said:
EinsteinsGhost wrote:
Number2 said:
ultimitsu wrote:
Number2 said:
EinsteinsGhost wrote:
Number2 said:
Now let me ask you a question. if you set you camera to M, keep shutter speed and aperture the same, change ISO from 100 to 200, do you think exposure has changed?
Click to expand...
Yes, by 1 stop.
Click to expand...
I think this explains it all. you have been told many times why ISO amplfication is not part of exposure. GB even gave you the link to an excellent article that explains the difference between brightness and exposure.
Click to expand...
Then you've missed the point. Are you sure you will return with identically exposed images if you captured a scene at different ISO settings?
Click to expand...
Identically exposed? yes, Identical image? no. Images are not identical because they have different brightness.
Click to expand...
In other words, you will get result 1-stop underexposed. Hence my earlier response (now in bold). I somehow suspect that you do use ISO settings in your camera. May I ask why you do?
Click to expand...
ISO setting does not influence exposure. ISO infuences either analog or digital (or both) gain to the signal. If the gain is digital, nothing else is done, but every number in the data is adjusted by a factor (of 2 for each doubling of the ISO). Some cameras even treat ISO as metadata only (most or all Sigmas for example).

If you shoot out-of-camera-JPG-images, setting an ISO which causes the camera to create as bright image as one wants to is usually important.

However, if you shoot RAW, and your camera is ISOless or close to it, you can just brighten in the raw converter to your taste.

Now, are you of the false opinion that if I take a picure in raw, and make two JPG versions of it in the raw converter, where one has been pushed to be 1 stop brighter, the exposure of has also changed? What if it is the camera which does the brightening instead of me afterwards? What if I shoot on a camera where ISO in raw files is just metadata?
Click to expand...
Unless you want to kill this thread quickly, follow the one we're having a discussion in. I have asked you a question. Skip adding unnecessary responses.
 
EinsteinsGhost said:
EinsteinsGhost wrote:
EinsteinsGhost said:
Great Bustard wrote:
EinsteinsGhost said:
EinsteinsGhost wrote:

So, the only reason you'd use ISO setting in your camera would be for OOC JPEG or for LCD reviews.
Click to expand...
Well, the LCD playback is a big deal for me. However, since I shoot Canon, which does not use ISOless sensors, there's also this:

http://www.dpreview.com/forums/post/52189226

You change the ISO to change the brightness of the LCD playback and/or OOC jpg. Also, with a non-ISOless sensor (such as Canon's sensors), the higher ISOs result in less noise than a lower ISO pushed to a given brightness. For example, ISO 1600 is less noisy than ISO 100 pushed four stops for a given exposure.
Click to expand...
Let me point at another contradiction again (just I did with your argument on ISO changing exposure but being irrelevant for exposure): See your statements in bold. Your arguments are a mess, really.
Click to expand...
It was a typo that I just corrected. Are you seriously that cognitively incapacitated that you could not figure that out? Good grief.
EinsteinsGhost said:
Ignoring more of that incoherence which has become your signature...
Click to expand...
It's not "incoherence" that you are ignoring, but it is "incoherence" that you actively pursue.
EinsteinsGhost said:
...why would shoot ISO-less if all you use ISO for is to review? In fact, shooting ISO-less makes it more difficult to review (a reason I usually stick with 1-2 stops only). If you didn't get this point of mine either, you make the choice to shoot ISO-less so you can keep ISO setting on your camera LOW (not high) which will present you with an underexposed review.
Click to expand...
Here we are:

http://www.dpreview.com/forums/post/42625308

and

http://www.dpreview.com/forums/post/38224181
EinsteinsGhost said:
EinsteinsGhost said:
EinsteinsGhost said:
Otherwise, you might as well get rid of any notion of ISO (and film sensitivity). Right?
Click to expand...
For cameras with ISOless sensors, all they need is an ISOless UI, and, yes, you can do away with ISO completely. Also, when shooting in manual mode (M) with Auto ISO and user definable safety shifts, once again, you don't need ISO.
Click to expand...
So, there is no need for Auto ISO, and especially if you don't go chimping around. Perhaps that explains why I am such a big proponent of manual ISO. ;)
Click to expand...
There is no need for an ISO setting on the camera, period. Even for a camera with a non-ISOless sensor, the photographer can decide if highlights or low noise is more important, and let the camera choose the ISO more quickly and intelligently than the photographer could.
EinsteinsGhost said:
EinsteinsGhost said:
EinsteinsGhost said:
So, why not post couple of examples that demonstrate this fine approach of yours? It can make for an excellent argument against those who whine and cry all day long about IQ issues at higher ISO (which would include YOU).
Click to expand...
See the links in the third and forth paragraphs...
Click to expand...
I asked you to demonstrate with couple of examples (see bold), not go parroting with the usual (again).
Click to expand...
I did. Good grief:

See the links in the third and forth paragraphs:

http://www.josephjamesphotography.com/equivalence/#iso

A common myth is that higher ISOs cause more noise. The effect of the ISO setting is to indirectly changes the f-ratio, shutter speed, and/or flash power depending on the metering mode we are in, as well as adjust the brightness of the LCD playback and/or OOC jpg. Higher ISOs result in more narrow apertures, faster shutter speeds, and/or less flash power than lower ISOs for a given scene luminance, which results in less light falling on the sensor, and thus more photon noise. In other words, it is the lesser amount of light falling on the sensor at higher ISOs than lower ISOs that results in greater noise at higher ISOs, not the higher ISO setting, per se.

Unlike film, the sensitivity of the sensor is fixed -- that is, the ISO setting does not affect the efficiency of the sensor. However, for sensors with noisy ADCs (Analog to Digital Conversion units), higher ISO settings result in less read noise than lower ISO settings. For example, the read noise for the Canon 5D3 at base ISO (100) is 33.1 electrons, drops to 18.2 electrons at ISO 200, and continues to drop until it finally levels off at around 3 electrons at ISO 3200. On the other hand, some sensors, like the Sony Exmor sensor in the Nikon D7000 and D800, have the same read noise throughout the entire ISO range. These types of sensors are referred to as "ISOless", although it's worth noting that even "non-ISOless" sensors usually become ISOless after some point in the ISO range.

For a camera with an ISOless sensor, the only reason for using higher ISOs is operational convenience, as no cameras currently have an ISOless UI (user interface). For example, let's say a photo of a scene at f/2.8 1/100 ISO 800 resulted in the desired output brightness. If we instead took the photo at f/2.8 1/100 ISO 100 and pushed the file three stops, in a RAW conversion, the resulting files would be the same, whereas if we did the same with a camera using an non-ISOless sensor, the ISO 800 photo would be less noisy than the ISO 100 photo (see here and here for demonstrations).

The disadvantage, then, of shooting at higher ISOs with a camera using an ISOless sensor is that the recorded file may very well oversaturate (blow) portions of the scene since portions well within the saturation limits of the pixel will be pushed outside the bit depth of the recorded file, whereas using the appropriate tone curve in the processing of a photo taken at base ISO could retain much more of the highlights (see here for a demonstration). However, since neither the output jpg brightness nor the LCD playback are tied to the camera's meter, operationally, using a camera with an ISOless sensor in an ISOless manner is very inconvenient.
EinsteinsGhost said:
EinsteinsGhost said:
Are you seriously asking that? I mean, are you really asking me to post a photo taken at f/2.8 1/100 ISO 1600 and a photo of the same scene taken at f/2.8 1/100 ISO 100 and pushed four stops in the conversion?
Click to expand...
Why would you have to push four stops in conversion? And yes, I'm seriously asking you to post a pair of samples. It will lead to a meaningful discussion.
Click to expand...
Seriously, it's amazing how cognitively impaired you are. The reason in explained in the text above, and the links demonstrate it. Get tested, for goodness sakes.
EinsteinsGhost said:
EinsteinsGhost said:
Well, as I said, the differences will be in terms of noise. For photos taken with an ISOless sensor, there will be no difference. For photos taken with a non-ISOless sensor, the ISO 100 photo will be more noisy.
Click to expand...
Don't worry about noise or dynamic range or color depth. I'm strictly working with exposure variables.
Click to expand...
The exposure variables are scene luminance, t-stop (usually closely approximated by f-ratio), and shutter speed.
EinsteinsGhost said:
EinsteinsGhost said:
EinsteinsGhost said:
When was the last time you adjusted ISO (or used Auto ISO), for anything but chimping?
Click to expand...
Well, I chimp all the time, so I need the LCD playback to show the desired brightness all the time. In addition, as I said, my camera does not sport an ISOless sensor, so I get less noisy photos by using a higher ISO than base ISO and pushing to the desired brightness.

Again, in neither case does ISO figure into exposure.
Click to expand...
Then there should be no need "to push" by the same number of stops you chose to reduce the sensitivity with. When you don't want to have to "push", you actually go begging for ISO.
Click to expand...
When you raise the ISO setting, it is simply an in-camera push that cannot be undone.
EinsteinsGhost said:
EinsteinsGhost said:
EinsteinsGhost said:
And why does camera need ISO for OOC JPEGs?
Click to expand...
Are you seriously asking that? Wow. The camera uses the ISO setting to determine the amplification that needs to be applied to the image file for the desired brightness.
Click to expand...
But you keep saying that ISO setting does not affect exposure.
Click to expand...
It does not, except as it indirectly affects the aperture, shutter speed, or scene luminance (if using flash).
EinsteinsGhost said:
EinsteinsGhost said:
However, the camera could just as well tie the LCD playback and OOC jpg brightness to the brightness of a zero meter, but they don't -- they use the ISO setting instead.
Click to expand...
Click to expand...
Yeah -- that.
 
Last edited:
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