Of course ISO is an exposure variable - when you are shooting digital

[Great Bustard]

tkbslc wrote:

Great Bustard wrote:

tkbslc wrote:

Great Bustard wrote:

tkbslc wrote:

Great Bustard wrote:

And here we are with a camera that has an ISOless sensor:

http://www.dpreview.com/forums/post/37235114

If we did the same with a camera that had a non-ISOless sensor, the pushed ISO 100 photo would be more noisy.

As "we" have been saying, the ISO setting is a matter of pre-processing the light that falls on the sensor, and, as such, is not an element in exposure, but an element in processing.

Thus, your challenge, and my answering that challenge, is irrelevant in terms of what exposure is and isn't.

If you had taken that shot with the same ISO and reduced shutter speed by 6 stops and then brightened it with RAW editing software, you'd have the same shot, too.

No, you'd have a rather different photo. You'd have a photo that was made with 64x (6 stops more) light. Big difference.

reducing the shutter speed decreases the light, but either way, I corrected for it with the RAW editor, just as those pushing the ISO do.

Apologies -- I misinterpreted "reduced shutter speed" and was thinking the exact opposite. In any case, the photos in the link above were shot with the same camera and exposure, thus the same amount of light and thus the same noise.

Your idea of reducing the shutter speed, and thus reducing the light, would make for a much more noisy photo.

In theory, anyway.

...you're of the opinion that putting 1/64 (6 stops less) light on the sensor will not result in a more noisy photo except "in theory"? Do tell.

 

[Sammy Yousef]

Great Bustard wrote:

You basically just admitted that unless a camera is ISOless, ISO Is part of th exposure.

You do know what an ISOless sensor is, right? It means that the read noise stays the same throughout the ISO range -- it has absolutely nothing to do with exposure.

So you're using exposure in the very narrow sense of the amount of light (lux) hitting the recorder, with no regard for changes to that recorder. Okay I'll concede that the way you (and the wikipedia article) define exposure you are correct.

HOWEVER in practical terms you cannot ignore ISO when exposing an image with most modern equipment. ISO is crucial to the quality of data that is retained from that exposure (your definition). The exposure and the sensitivity of the sensor are intimately linked. I could replace the sensor with a piece of non-photographic paper and call what I make an exposure by your literal and narrow definition. I've exposed the paper - it just hasn't reacted. The recording medium affects the results captured by the exposure.

 

[Sammy Yousef]

bobn2 wrote:

Sammy Yousef wrote:

Great Bustard wrote:

Sammy Yousef wrote:

Put EVERYTHING in manual. Exposure. ISO. WB. Flash power.

Shoot correctly exposed at ISO6400.

Re-shoot but change ISO to 100. Make no other changes.

Boost the ISO 100 shot to 6400 and compare with the previous. If there is no difference compared to the correctly exposed shot, you're right. I think you'll find you're not.

If you want to blame the software, then find other software. If you can't, you're still wrong for all practical cases.

And here we are with a camera that has an ISOless sensor:

http://www.dpreview.com/forums/post/37235114

If we did the same with a camera that had a non-ISOless sensor, the pushed ISO 100 photo would be more noisy.

You basically just admitted that unless a camera is ISOless, ISO Is part of th exposure. I don't see how that can be taken any other way. You do not get equivalent exposures when changing the ISO.

Basically he said nothing of the sort. The ISO setting on an ISOful camera is something that you need to take account of, because it affects the performance of the camera. But if you want to tweak the last n'th out of your camera, then the way you should be working is making exposure decisions independent of 'ISO' then setting the ISO control to the optimum setting to match your exposure (which often won't be the position where the selected exposure is nominal for that ISO setting)

Independent has a very specific meaning. Your camera has very limited range. If you could shoot independently you could always pick shutter and aperture to suit you. But I don't know of a camera that shoots at ISO 1,000,000, so I better let that ISO affect my decision.

Which type is more common? ISOless or non-ISOless?

Difficult question. Most probably ISOless. The vast majority of CCD cameras were/are ISOless, and a good few of the newer CMOS.

If that were true you could ignore ISO and set it later. You can't, as you said above.

I love my D70 cameras because they have a flash sync of 1/500th, but I don't go around saying you can shoot with flash sync of 1/500th on all cameras then state that it's only for certain models.

I've never shot a model who could move that fast.

Irrelevant. Other people are interested in shooting subjects that do move that fast and much faster. If you wish to limit yourself to studio photography, that's your choice, but I suggest broadening your horizons a little. Some astrophotography and a little action shooting may give you a less narrow perspective.

 

[Sammy Yousef]

tomtom50 wrote:

Leonard Migliore wrote:

tomtom50 wrote:

Ahh, but isn't this the same as M + autoiso? Nope. Try using exposure compensation in M + autoiso! In Tv mode you can use exposure compensation, and it has all the goodness it has in other auto modes.

Perhaps a bit off topic, but that's a Canon disease. On Nikons, you can indeed use exposure compensation in manual with auto ISO and it works just like Pentax's Tv mode as you describe it.

I did not know that. S Pentax & Nikon are smart, Canon is semi-smart, and Sony remains obtuse (No autoiso with user set aperture and shutter, period)

I preferred the Nikon way of doing things before they ruined the interaction with TTL flash.

For maximum control while still allowing automatic exposure, you really want modes that allow you to control 2 of the parameters in the exposure triangle and let the 3rd float. With Nikon you use to get that using:

1. Aperture and shutter to be set, ISO to float - M with auto ISO on

2. ISO and shutter to be set, aperture to float - S with auto ISO off

3. ISO and aperture to be set, shutter to float - A with auto ISO off

If you want to give up control to allow 2 of the 3 parameters to float you can also do it.

4. Aperture set, shutter and ISO to float - A with auto ISO on

5. Shutter set, aperture and ISO to float - S with auto ISO on

6. ISO set, aperture and shutter to float - P with auto ISO off

If you want all 3 to be decided by the camera you are giving up total control

7. Aperture, shutter, ISO set by camera - P with auto ISO on, or full auto

It is a real shame that Nikon does not allow settings to control interaction of flash power with the above modes. A toggle setting to allow flash power to be boosted ahead of ISO, or vice versa would be ideal in terms of giving total control.

 

[Andre Affleck]

bobn2 wrote:

Andre Affleck wrote:

I think those of us who believe this are subconsciously self-reflecting. GB has even gone on record saying he enjoys watching the technically challenged squirm out of discussions. Are you sure it is not us who are trying to feel more important with this "entertainment"?

Look, the misuse of the term by these poor saps has nothing to do with sounding important. It is merely that fact that traditional photographers of much more pragmatic than sensor designers. Simple as that, nothing more. When they set exposure they consider all three so they just call it exposure. So? There is nothing more to be gained by pro photographers by asking them to do any different. Reducing noise by 8% doesn't sell them more photos. Got nothing to do with feeling important.

I disagree.

How can you disagree when every other statement I made was fairly accurate (aside from the one opinion). I think you'll agree that:

• Traditional photographers are more pragmatic than sensor designers
• When they set exposure they consider all three [parameters]
• Reducing noise by 8% doesn't sell them more photos.

What is there to disagree with? I know you came from the film era. You know very well that most photographers treated ISO as just one of the 3 parameters when setting exposure. It was just practical to include it and just call it exposure. Remember the sunny 16 rule of "exposure"?

"On a sunny day set aperture aperture to f/16 and shutter speed to the [reciprocal of the] ISO film speed [or ISO setting] for a subject in direct sunlight."

Maybe because you worked in a lab did you find it beneficial to differentiate it, but the rest of us really didn't.

I think the average person with a camera, who didn't consider themselves a photographer would probably never sue the word 'exposure' or 'under exposed' or 'over exposed'. They would talk about the picture being 'too dark' or 'too light'.

That's probably accurate of most people, but I'm referring to professional photographers, not average people.

'Exposure' is a jargon word, and people adopt jargon either because a precise vocabulary is required for precise communication or to illustrate membership of an 'expert' fraternity. I can't see why else they would do it, because calling 'brightness' 'exposure' just makes communication more difficult.

You wouldn't do it for reasons of pragmatism, if you were pragmatic, you'd use the existing word that allowed you to communicate most widely.

...says the not-so-pragmatic sensor designer No, it was simply more practical since most of us didn't didn't need to know the difference and still managed to capture wonderful images. Exposure was more of a nominal target, right or wrong. The lab did the rest and we accepted the consequences, and frankly, those consequences had very little to do with the role of ISO.

So lets just round them up in a public arena and persecute their ignorance for our measly entertainment. Oooo, can I get front row? Maybe GB can sell the screen play to the producers of Hunger Games III.

They throw themselves to the lions, often very aggressively. People who are just wrong don't get treated harshly. Even people who insist on remaining wrong aren't. The ones who are are the ones who insist, in the face of every bit of evidence and argument that they are right, the others are wrong and will stop at no insult or defamation when they run out of evidence and argument. They're fair game.

Sure but I'm questioning the motives of the lions. Lions don't' hunt in order to teach prey self-preservation. They hunt to eat. Too many of them only come out when they want to enjoy a good meal, or worse yet, to enjoy a good kill.

 

[gollywop]

Sammy Yousef wrote:

Great Bustard wrote:

You basically just admitted that unless a camera is ISOless, ISO Is part of th exposure.

You do know what an ISOless sensor is, right? It means that the read noise stays the same throughout the ISO range -- it has absolutely nothing to do with exposure.

So you're using exposure in the very narrow sense of the amount of light (lux) hitting the recorder, with no regard for changes to that recorder. Okay I'll concede that the way you (and the wikipedia article) define exposure you are correct.

HOWEVER in practical terms you cannot ignore ISO when exposing an image with most modern equipment. ISO is crucial to the quality of data that is retained from that exposure (your definition). The exposure and the sensitivity of the sensor are intimately linked. I could replace the sensor with a piece of non-photographic paper and call what I make an exposure by your literal and narrow definition. I've exposed the paper - it just hasn't reacted. The recording medium affects the results captured by the exposure.

I could replace your brains with Pablum. What comes through your eyes and ears would be just the same.

But do you really think this is a situation that warrants consideration?

Well ... now that I think about it ...
--
gollywop

 

[pavi1]

Not just with digital. It was with film. You just had to decide on the ISO 24 -36 shots at a time. With digital you can change the ISO for each shot.

If I set ISO to 0(zero) on your camera, is exposure on at noon on a cloudless day 1/0 @ f16?

 

[gollywop]

toomanycanons wrote:

The thread subject that just keeps on going.

No, I didn't read the previous 393 replies spread across three threads. Here's what I have to say:

Since my Nikon DSLRs are clean to ISO 1600 (or more) it's a non-issue me changing ISO from 100 to at least 800 or even 1600. The shutter speed doubles every time I up the ISO (100-200-400-800 etc) and if I think my shutter is going to be too low, I just up the ISO.

Is that even the topic that's being discussed here?

No. But don't worry about it. You're no worse (or better) off for jumping in without knowing what you were jumping in to. Continue your rest period.

--
gollywop

 

[Great Bustard]

Sammy Yousef wrote:

Great Bustard wrote:

You basically just admitted that unless a camera is ISOless, ISO Is part of th exposure.

You do know what an ISOless sensor is, right? It means that the read noise stays the same throughout the ISO range -- it has absolutely nothing to do with exposure.

So you're using exposure in the very narrow sense of the amount of light (lux) hitting the recorder, with no regard for changes to that recorder. Okay I'll concede that the way you (and the wikipedia article) define exposure you are correct.

Excellent!

HOWEVER in practical terms you cannot ignore ISO when exposing an image with most modern equipment.

Who says to ignore ISO? Rather, ISO is an element of [pre-] processing, not exposure. Think of it like white balance.

ISO is crucial to the quality of data that is retained from that exposure (your definition). The exposure and the sensitivity of the sensor are intimately linked. I could replace the sensor with a piece of non-photographic paper and call what I make an exposure by your literal and narrow definition. I've exposed the paper - it just hasn't reacted. The recording medium affects the results captured by the exposure.

Absolutely.

 

[Iliah Borg]

tomtom50 wrote:

http://www.luminous-landscape.com/r...om_d_e_m1_rolling_field_report.shtml#saturday

Just published by Michael Reichmann, author of many books & videos on photography and video, reviewing the new Olympus E-M1.

He is a very good photographer, and very technically astute:

http://www.luminous-landscape.com/r...om_d_e_m1_rolling_field_report.shtml#saturday

"Another thing that Oly has done right is that it allows ISO to be used as the third exposure variable. In other words, you can go to Manual mode, set the shutter speed and the aperture that you need, and then let the camera automatically ride the ISO so that a proper exposure is achieved. And to put icing on the cake, one of the custom settings allows you to set which shooting modes auto ISO will work in. Now, that's customizibility!"

This is how people talk because it conveys the meaning. I know what he means. Everyone arguing knows what he means. Some say he is "wrong".

It is worse than wrong, it is misleading.

The problem is that the wrong understanding of what exposure means results in wrong decisions while shooting, and suboptimal results.

> very technically astute

How would you know?

 

[tkbslc]

Is ISO technically a factor in the camera's exposure of the sensor by pure definition? No.

Is ISO an important setting in creating actual photos? Obviously.

Pedantry vs Practice.

 

[Detail Man]

tkbslc wrote:

Is ISO technically a factor in the camera's exposure of the sensor by pure definition? No.

Is ISO an important setting in creating actual photos? Obviously.

Pedantry vs Practice.

What is the opposite (or better termed, the functional inverse) of "pedantry" ? Please advise.

Please also answer me this. Would you prefer "sophistry" to "pedantry". If so, do explain why.

DM ...

 

[Andre Affleck]

Iliah Borg wrote:

tomtom50 wrote:

http://www.luminous-landscape.com/r...om_d_e_m1_rolling_field_report.shtml#saturday

Just published by Michael Reichmann, author of many books & videos on photography and video, reviewing the new Olympus E-M1.

He is a very good photographer, and very technically astute:

http://www.luminous-landscape.com/r...om_d_e_m1_rolling_field_report.shtml#saturday

"Another thing that Oly has done right is that it allows ISO to be used as the third exposure variable. In other words, you can go to Manual mode, set the shutter speed and the aperture that you need, and then let the camera automatically ride the ISO so that a proper exposure is achieved. And to put icing on the cake, one of the custom settings allows you to set which shooting modes auto ISO will work in. Now, that's customizibility!"

This is how people talk because it conveys the meaning. I know what he means. Everyone arguing knows what he means. Some say he is "wrong".

It is worse than wrong, it is misleading.

The problem is that the wrong understanding of what exposure means results in wrong decisions while shooting, and suboptimal results.

Sure, but can you quantify those suboptimal results? It would be interesting to see an image that was unacceptably compromised because of one's misinterpretation of exposure.

In fact that would be a great topic for he next thread. "Show us your images ruined by your misinterpretation of exposure".

 

[Iliah Borg]

can you quantify those suboptimal results, even if subjectively?

Subjectively quantify? Nice.

 

[Andre Affleck]

Iliah Borg wrote:

can you quantify those suboptimal results, even if subjectively?

Subjectively quantify? Nice.

Come on now, you just count how many photos you feel were unacceptable.

Well can you?

 

[Sammy Yousef]

Great Bustard wrote:

Sammy Yousef wrote:

There is a difference between boosting sensitivity during reading and boosting it afterwards. The recorded information is different and is not equivalent.

For cameras with non-ISOless sensors, that is correct. However, neither here nor there. Exposure is about the light falling on the sensor (specifically, the light per area falling on the sensor), not the processing of that light.

I'll say it again. By the definition you provided, if I expose a piece of paper to that amount of light I am making the same "exposure" as if I had the world's most advanced sensor in it's place. Both "see" or are "exposed to" the same amount of light.

This does not match the way the word exposure gets used in practice - e.g. "exposure triangle".

Would you argue that my 6D at f/2.8 1/200 ISO 100 has the same exposure as my 5D at f/2.8 1/100 ISO 100 because it has twice the QE (Quantum Efficiency -- the proportion of light falling on the sensor that is recorded)?

And now you've really decided to confuse things. Quantum Efficiency of a sensor does not equal ISO setting.

 

[attomole]

tkbslc wrote:

Is ISO technically a factor in the camera's exposure of the sensor by pure definition? No.

Is ISO an important setting in creating actual photos? Obviously.

Pedantry vs Practice.

With you on this.

The meaning of the language we use is dynamic it changes with use over time, its become common to say a photograph that is a bit dark is underexposed, when "a bit dark" is technically a better description

Photographic exposure may be defined in the strictest of mathematical terms as the light collected at the film plane as has been described in these discussions we cant get away from that, independent of any gain settings (ISO) on the camera or post processing.

However if people use it to describe a photograph that is a bit to dark as "maybe a stop underexposed", I get it! and am comfortable with that usage even if it is not strictly correct in the maths.

By way of justification, I would say that presenting an image is a two step process, recording in camera and post processing, it was ever the case even in printing days (although the logic was revised I usually printed about 1/3 stop over (two dark) as i didn't take into account dry down and the lighting in the darkroom when evaluating my printing.

Therefore I am OK with two meanings for exposure the strictest mathematical one and one which is applied two the final image that is just evolved grammar, and effectively multiplied by gain settings in the camera and plus post processing applied enhance the aesthetic qualities , regardless of if they are camera settings or done on your computer.

Therefore yes sticking with the strictest mathematical definition is pedantic

 

[Great Bustard]

Sammy Yousef wrote:

Great Bustard wrote:

Sammy Yousef wrote:

There is a difference between boosting sensitivity during reading and boosting it afterwards. The recorded information is different and is not equivalent.

For cameras with non-ISOless sensors, that is correct. However, neither here nor there. Exposure is about the light falling on the sensor (specifically, the light per area falling on the sensor), not the processing of that light.

I'll say it again. By the definition you provided, if I expose a piece of paper to that amount of light I am making the same "exposure" as if I had the world's most advanced sensor in it's place. Both "see" or are "exposed to" the same amount of light.

This does not match the way the word exposure gets used in practice - e.g. "exposure triangle".

Exactly. And that is why the "exposure triangle" is not about exposure, but about brightness.

Would you argue that my 6D at f/2.8 1/200 ISO 100 has the same exposure as my 5D at f/2.8 1/100 ISO 100 because it has twice the QE (Quantum Efficiency -- the proportion of light falling on the sensor that is recorded)?

And now you've really decided to confuse things. Quantum Efficiency of a sensor does not equal ISO setting.

Cha-ching! ISO is no more a part of exposure than is QE.

 

[tkbslc]

Detail Man wrote:

tkbslc wrote:

Is ISO technically a factor in the camera's exposure of the sensor by pure definition? No.

Is ISO an important setting in creating actual photos? Obviously.

Pedantry vs Practice.

What is the opposite (or better termed, the functional inverse) of "pedantry" ? Please advise.

Please also answer me this. Would you prefer "sophistry" to "pedantry". If so, do explain why.

DM ...

When one reads a book on "exposure", what they really want to learn is to how to better capture photos as intended. ISO is an important part of that process. Arguing for hundreds of posts that it isn't technically an exposure setting does not help anyone take better pictures.

Arguing technical detail just for detail's sake is the definition of pedantry.

 

[Andre Affleck]

Great Bustard wrote:

Sammy Yousef wrote:

Great Bustard wrote:

Sammy Yousef wrote:

There is a difference between boosting sensitivity during reading and boosting it afterwards. The recorded information is different and is not equivalent.

For cameras with non-ISOless sensors, that is correct. However, neither here nor there. Exposure is about the light falling on the sensor (specifically, the light per area falling on the sensor), not the processing of that light.

I'll say it again. By the definition you provided, if I expose a piece of paper to that amount of light I am making the same "exposure" as if I had the world's most advanced sensor in it's place. Both "see" or are "exposed to" the same amount of light.

This does not match the way the word exposure gets used in practice - e.g. "exposure triangle".

Exactly. And that is why the "exposure triangle" is not about exposure, but about brightness.

Obviously, these people just don't have the mental capacity to grasp this. You're just gonna have to post an example showing how calling it Exposure Triangle produced unacceptable results, or else these harebrained utilitarians will never get it.