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

[Andre Affleck]

Great Bustard wrote:

Andre Affleck wrote:

Great Bustard wrote:

tkbslc wrote:

Great Bustard wrote:

tkbslc wrote:

Great Bustard wrote:

So, "exposure = brightness" and there's no reason to distinguish between them? That is, we don't care about the exposure, in the sense that the word is defined, as it is unimportant -- what we care about is the "exposure" in the sense of how bright or dark the photo appears?

How does distinguishing between them assist the photographer in creating better images?

It won't for the jpg photographer, but will for the RAW photographer.

You've linked to many examples where ISO is proven to be irrelevant.

I can't imagine, since the ISO setting is relevant. In fact, I just made a post demonstrating that:

http://www.dpreview.com/forums/post/52217114

It's simply that ISO is an element in [pre-] processing, not exposure.

Right, and if you thought ISO was an element of exposure you would still reach the same conclusion.

What conclusion would that be, exactly?

That if set my exposure so that my ISO was at native, boosted my "fill in the blank" afterword, I get higher DR. See I confused ISO with exposure and didn't even call it brightness and still got the idea. That example is more about technique and less about principle.

 

[Great Bustard]

Andre Affleck wrote:

Great Bustard wrote:

Andre Affleck wrote:

Great Bustard wrote:

tkbslc wrote:

Great Bustard wrote:

tkbslc wrote:

Great Bustard wrote:

So, "exposure = brightness" and there's no reason to distinguish between them? That is, we don't care about the exposure, in the sense that the word is defined, as it is unimportant -- what we care about is the "exposure" in the sense of how bright or dark the photo appears?

How does distinguishing between them assist the photographer in creating better images?

It won't for the jpg photographer, but will for the RAW photographer.

You've linked to many examples where ISO is proven to be irrelevant.

I can't imagine, since the ISO setting is relevant. In fact, I just made a post demonstrating that:

http://www.dpreview.com/forums/post/52217114

It's simply that ISO is an element in [pre-] processing, not exposure.

Right, and if you thought ISO was an element of exposure you would still reach the same conclusion.

What conclusion would that be, exactly?

That if set my exposure so that my ISO was at native, boosted my "fill in the blank" afterword, I get higher DR.

So you are setting your exposure (aperture, f-ratio, and/or shutter speed) based on your ISO setting? In other words, you are shooting in "noise priority mode"?

In any case, the lower the ISO setting the greater the DR, although with non-ISOless sensors, the decreasing read noise offsets the decreasing saturation so that the DR may be relatively constant all the way up to ISO 800, even. However, just because the DR is [approximately] the same doesn't mean the IQ is the same:

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

However, with a camera using an ISOless sensor, you will always get the greatest DR (and highest IQ) at base ISO (assuming, of course, we're shooting RAW and know how to apply the appropriate tone curve in the conversion), but it comes with the operational disadvantage that the brightness of the LCD playback and OOC jpg are tied to the ISO setting as opposed to a zeroed meter.

See I confused ISO with exposure and didn't even call it brightness and still got the idea.

What idea was it that you got?

 

[JamieTux]

tomtom50 wrote:

Fir film cameras exposure is aperture and shutter speed, because those are the dials you twist picture optimally bright balancing what you need for other attributes like dof, sharpness, and blur. Adjusting your camera to get the right brightness balancing the other attributes needed a good strong word because that was an important part of taking good pictures.

What??? The exposure is still the same - why do you feel the need to redefine it for no reason?

Now with digital camera we have three settings to get the right brightness balancing the other attributes. We know have new attributes in the mix, DR, detail, and noise

You always have had - how many film shooters expose reala as 80ASA instead of 100, or use(d) Portra for the lattitude it gave, or found other films that they could stretch the limits of and fix in post?

The core thing we are doing (adjusting camera settings to get the right brightness balancing other attributes) hasn't changed, so neither should the word. That would be the tail wagging the dog. Exposure is not a hard and fast definition of which dials were used to get the right best picture in film days. It is the technique of making the settings that balance other attributes and get the right brightness when you are taking a picture now.

Correct the exposure was the f-stop and shutter speed you used, the brightness of the final image was set by the developing of the negative or slide and the printing (lots of film developing companies will allow you to request the film to be push or pull processed too if you look at the extras).

The difference now is that you are mixing up the capturing of the image and the showing of the finished product and now want to redefine words for some reason.

Good usage is usage that successfully communicates the relevant information, and becomes widespread. Technology changes and the words meanings change as well. That's why we dial phone numbers on phones that have no dials.

Right but surely you can see that nothing has changed? You are doing the exact same thing that film shooters were doing except seeing the results of pushing or pulling the film straight away.

Pentax is the camera maker that gets this

One of the camera makers that gets it.

They have PASM and Tv. Tv has the user set aperture and shutter and the camera automates ISO. Very nice photographing children in bad light. Lens wide open, shutter as needed to get the blur down, and the camera will set ISO.

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.

Have you used a Sony A99? Exposure compensation in M works - so it is the same, on my Panasonic GH3 there is no auto iso in M mode - so that one brush fits all doesn't work.

Treating autoiso as another exposure variable gives the options you want to take pictures in more situations, while a fuddy duddy adherence to old definitions makes camera that are less useful and have confusing naming - "M + autoiso? but M means MANUAL"

Reword this as treating autoiso as another brightness variable and you're pretty much there.

Sony is bad At least on my two Sonys (RX100 and NEX 3n) you don't even get M + autoiso, and it is a pain and a reason I often prefer my Canon.

Sony are great at this - read the above about the A99, it's different manufacturers and models. However it does lack in another way - if I'm in A mode I can't tell the camera what the minimum shutter speed I want it unlike my Nikon D700.

Flexibility, people. The only static language is a dead language.

Correct, but nothing in your post suggests why ISO should be considered part of the exposure.

A much shorter statement would be:

"Ask most photographers what exposure is and they will tell you that it is the brightness of the image and is controlled through the use of the aperture, shutter speed and the ISO of the sensor or film"

That would be a valid reason to change the meaning - the reasons that you gave above haven't changed in the last 100 years....

 

[Great Bustard]

bobn2 wrote:

tkbslc wrote:

It won't for the jpg photographer, but will for the RAW photographer.

You've linked to many examples where ISO is proven to be irrelevant. So how would choosing the ISO that would leave one with a good JPEG leave one with a worse RAW file?

I don't quite agree with Joe's answer.

*GASP*

I think the benefits of knowing what the exposure is spread to both JPEG and raw files, but it's easier to optimise with raw files. Start out with the information that the higher the exposure the better the noise and DR IQ. This is, for a start that the exposure triangle confuses many about. They think noise is to do with 'ISO' when it's directly connected to exposure. So, whet you do if you're guided by ISO is guess the exposure that you're going to be using first. Then you meter the scene and adjust the exposure to be what you guessed in the first place. A better photographer might notice thet their guess was off and select a different exposure by changing the ISO, or have auto ISO engaged to do it for them. Whatever, what you've done is set the exposure to some arbitrary value, rather than the highest the your pictorial requirements and the lighting might have given you. The photographer who is aware of what exposure is sets the shutter and aperture to give the biggest exposure according to his pictorial constraints, then adjusts the processing (or ISO) to suit, and gets a less noisy image as a result.

For sure I can see dialing in EC correction for OOC jpgs, depending on how the camera is metering a particular scene, but I'm unclear on how one would decouple the ISO setting from the exposure setting to achieve a better jpg.

 

[Andre Affleck]

bobn2 wrote:

tkbslc wrote:

It won't for the jpg photographer, but will for the RAW photographer.

You've linked to many examples where ISO is proven to be irrelevant. So how would choosing the ISO that would leave one with a good JPEG leave one with a worse RAW file?

I don't quite agree with Joe's answer. I think the benefits of knowing what the exposure is spread to both JPEG and raw files, but it's easier to optimise with raw files. Start out with the information that the higher the exposure the better the noise and DR IQ. This is, for a start that the exposure triangle confuses many about. They think noise is to do with 'ISO' when it's directly connected to exposure. So, whet you do if you're guided by ISO is guess the exposure that you're going to be using first. Then you meter the scene and adjust the exposure to be what you guessed in the first place. A better photographer might notice thet their guess was off and select a different exposure by changing the ISO, or have auto ISO engaged to do it for them.

No they wouldn't. Think about what you just said. Even if you thought ISO was responsible for noise you would still select a different ISO to maximize light and reduce noise. You reach the same conclusion regardless whether you though ISO was part of exposure or not.

 

[Andre Affleck]

Great Bustard wrote:

Andre Affleck wrote:

Great Bustard wrote:

Andre Affleck wrote:

Great Bustard wrote:

tkbslc wrote:

Great Bustard wrote:

tkbslc wrote:

Great Bustard wrote:

So, "exposure = brightness" and there's no reason to distinguish between them? That is, we don't care about the exposure, in the sense that the word is defined, as it is unimportant -- what we care about is the "exposure" in the sense of how bright or dark the photo appears?

How does distinguishing between them assist the photographer in creating better images?

It won't for the jpg photographer, but will for the RAW photographer.

You've linked to many examples where ISO is proven to be irrelevant.

I can't imagine, since the ISO setting is relevant. In fact, I just made a post demonstrating that:

http://www.dpreview.com/forums/post/52217114

It's simply that ISO is an element in [pre-] processing, not exposure.

Right, and if you thought ISO was an element of exposure you would still reach the same conclusion.

What conclusion would that be, exactly?

That if set my exposure so that my ISO was at native, boosted my "fill in the blank" afterword, I get higher DR.

So you are setting your exposure (aperture, f-ratio, and/or shutter speed) based on your ISO setting? In other words, you are shooting in "noise priority mode"?

Huh?

In any case, the lower the ISO setting the greater the DR, although with non-ISOless sensors, the decreasing read noise offsets the decreasing saturation so that the DR may be relatively constant all the way up to ISO 800, even. However, just because the DR is [approximately] the same doesn't mean the IQ is the same:

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

However, with a camera using an ISOless sensor, you will always get the greatest DR (and highest IQ) at base ISO (assuming, of course, we're shooting RAW and know how to apply the appropriate tone curve in the conversion), but it comes with the operational disadvantage that the brightness of the LCD playback and OOC jpg are tied to the ISO setting as opposed to a zeroed meter.

See I confused ISO with exposure and didn't even call it brightness and still got the idea.

What idea was it that you got?

The idea that your trying to run out the thread so you don't have to acknowledge the point.

 

[Detail Man]

Great Bustard wrote:

bobn2 wrote:

tkbslc wrote:

It won't for the jpg photographer, but will for the RAW photographer.

You've linked to many examples where ISO is proven to be irrelevant. So how would choosing the ISO that would leave one with a good JPEG leave one with a worse RAW file?

I don't quite agree with Joe's answer.

*GASP*

I think the benefits of knowing what the exposure is spread to both JPEG and raw files, but it's easier to optimise with raw files. Start out with the information that the higher the exposure the better the noise and DR IQ. This is, for a start that the exposure triangle confuses many about. They think noise is to do with 'ISO' when it's directly connected to exposure. So, whet you do if you're guided by ISO is guess the exposure that you're going to be using first. Then you meter the scene and adjust the exposure to be what you guessed in the first place. A better photographer might notice thet their guess was off and select a different exposure by changing the ISO, or have auto ISO engaged to do it for them. Whatever, what you've done is set the exposure to some arbitrary value, rather than the highest the your pictorial requirements and the lighting might have given you. The photographer who is aware of what exposure is sets the shutter and aperture to give the biggest exposure according to his pictorial constraints, then adjusts the processing (or ISO) to suit, and gets a less noisy image as a result.

For sure I can see dialing in EC correction for OOC jpgs, depending on how the camera is metering a particular scene, but I'm unclear on how one would decouple the ISO setting from the exposure setting to achieve a better jpg.

I concur with Obe-Wan KenBobby, comrade. Assumimg that one has tested how their preview histogram tends to look near the top of the RAW ADU channels (and of course this is an imperfect sytem, etc.), the same benefits that accrue in my DMC-LX3 RAWs accrue to my (simultaneously recorded) JPGs.

There do exist some potential subtleties with this - i.e., Olympus designs which impose mandatory (additional) JPG channel highlight gain-reduction. That's why I use Panasonic models.

At any rate, one can still manage to make a reasonably good effort of maximizing sensor-level Exposure, and then raise ISO value only as much as necessary to get close to a desired JPG Brightness level. If one slightly slows Shutter Speed in order to tweak the JPG Brightness, so what ?

I suspect that you have (somewhat understandably) elected to not seem to overly "encourage" JPG-shooters. Nevertheless, (some) constructive measures can (still) be taken to improve JPG SNRs.

DM ...