Pls show examples where increasing brightness in post better than increasing ISO.

Started Oct 1, 2013 | Discussions
Andre Affleck Senior Member • Posts: 2,362
Re: Pls show examples where increasing brightness in post better than increasing ISO.

bobn2 wrote:

Andre Affleck wrote:

Andre Affleck wrote:

PhilPreston3072 wrote:

With the latest sensors, some have been proclaiming it's better to shoot at base ISO and increase brightness in post rather than increase ISO in camera.

I would like to see some examples of this. Are there any examples where increasing brightness in post delivers better IQ than increasing ISO in camera? And please, disable all NR settings.

bobn wrote here :

So, in the direct route, you would set the maximum exposure (subject to shake and the rest) and then set the brightening to match, whereas the other way you guess at the maximum exposure (via setting a guesstimate on the ISO dial). What most people will do, who don't know that it is exposure which matters, is centre the meter (or let the camera do it) and that will usually result in a lower exposure than had they set the maximum in the first place. No matter how you argue, that is how it really is. People using the ISO first technique will vary rarely set the maximum exposure

Not true, one starts raising ISO when they are already aperture and shutter limited.

Even so, it's unlikely that they will set the maximum exposure, simply because of what people think they have to do, and what they think their priorities. Somehow they will arrive at what they think is the right ISO for shooting, maybe by trial end error as you suggest and possibly just by making a guess, which is the impression that I get from people about setting ISO. You often get statements like '1600 lets me get the shutter speed I need'. Anyhow, however they get there, they now are at the ISO that they want to work. Then they centre the meter (maybe with some EC) to 'nail' the exposure, which means adjusting for some fixed output brightness at that ISO. To do that, they will almost always get a smaller exposure than they need. Supposing they decide that the DOF and motion blur are alright, they'll shoot, even though they might still have been alright up to half a stop more exposure. If they don't think they'll be alright, they'll raise the ISO (usually by a whole stop, I'd guess) and then centre the meter, and the same situation applies.

I think the reason why people are inclined to do what you suggest is because cameras are ergonomically designed that way. They are not designed with exposure as a priority. This is probably another throw back from the film days. One uses EC to fine tune exposure because it is intended to be used that way conveniently, and because the ISO control is buried in a menu somewhere. In addition, you can't simultaneously adjust ISO while watching the exposure meter. The cameras is almost forcing you to do the wrong thing by design.

I think it would be great if they allowed you to remap that dial to adjust ISO instead. Ultimately, ISO-less is the way to go, hopefully soon.

Only when by co-incidence does the maximum exposure that their pictorial constraints allow is the same as the one that centres the meter at that ISO, will they have maximised the exposure, I don't think it often happens.

In any case, even if it does, the rigmarole that they have gone through to get there is a whole lot longer than the simple route, set the aperture and shutter for the largest exposure that your pictorial constraints allow

Using what method to determine that maximum exposure? The camera meter is still tied to whatever ISO you are on and doesn't protect highlights well. If you rely on feedback from a histogram or preview, that too is tied to an even more arbitrary ISO. It would be nice if manufacturers would provide a raw histogram, but again cameras are not designed with these priorities in mind.

So I'm still not convinced it is your exposure philosophy that is responsible for poor choices.

Andre Affleck Senior Member • Posts: 2,362
Re: examples where increasing brightness in post is better than increasing ISO.

gollywop wrote:

PhilPreston3072 wrote:

gollywop wrote:

PhilPreston3072 wrote:

edu T wrote:

These after-brillig shots by Pierre Sottas with a D7000 are a classical example (AFAIK perhaps "the" one). This clear-cut "slain the jabberwocky and bring us its head" evidence was discussed here.

Captions by the author:

"A shot at ISO 6400, 1/30, f2.0 with very bad lightning conditions...

"...and the shot at ISO 100, 1/30, f2.0 (same exposure) and boosted 6 stops in RPP with highlights compression. No post-processing, EXIF should be intact."

(Can't help but notice that back then the angry mob of villagers wielding torches and forks was smaller and/or less frumious...)

I would say the ISO6400 has been disadvantaged here. The highlight areas of the verandah are already blown at this exposure. He should have reduced the exposure until those highlights weren't clipped at ISO6400 and then applied the same exposure settings for ISO100, and then applied shadow recovery if necessary.

They are the same exposure, and he got the shot he wanted. Reducing the exposure would simply give a shot a more noise. I would say ISO 6400 has a disadvantage, but it hasn't been disadvantaged.

You're missing the point here guys. The purpose of these shots was to compare the performance of ISO6400 with ISO100 pushed, it was not about obtaining best image quality. You can't properly compare ISO6400 with ISO100 by blowing out the verandah highlights and then attempt to recover the highlights when they were excluded in the first place.

If I was taking this shot and saw the verandah highlights blowing at ISO6400 I'd naturally lower the ISO until the highlights were no longer clipping. If the poster wanted to compare best image quality then this is what he should have done.

Well, not exactly missing the point since you didn't say "reduce ISO" to begin with; you said "reduce exposure." That's a rather different thing, and there certainly was no need to reduce exposure -- which is the point we guys were making.

Not to open any sore wounds, but it is interesting that the other poster still arrived at the correct settings to maintain highlights, even though he understood it as reducing exposure. Just sayin'

bobn2
bobn2 Forum Pro • Posts: 60,496
Re: Pls show examples where increasing brightness in post better than increasing ISO.

jvkelley wrote:

bobn2 wrote:

Andre Affleck wrote:

Andre Affleck wrote:

PhilPreston3072 wrote:

With the latest sensors, some have been proclaiming it's better to shoot at base ISO and increase brightness in post rather than increase ISO in camera.

I would like to see some examples of this. Are there any examples where increasing brightness in post delivers better IQ than increasing ISO in camera? And please, disable all NR settings.

bobn wrote here :

So, in the direct route, you would set the maximum exposure (subject to shake and the rest) and then set the brightening to match, whereas the other way you guess at the maximum exposure (via setting a guesstimate on the ISO dial). What most people will do, who don't know that it is exposure which matters, is centre the meter (or let the camera do it) and that will usually result in a lower exposure than had they set the maximum in the first place. No matter how you argue, that is how it really is. People using the ISO first technique will vary rarely set the maximum exposure

Not true, one starts raising ISO when they are already aperture and shutter limited.

Even so, it's unlikely that they will set the maximum exposure, simply because of what people think they have to do, and what they think their priorities. Somehow they will arrive at what they think is the right ISO for shooting, maybe by trial end error as you suggest and possibly just by making a guess, which is the impression that I get from people about setting ISO. You often get statements like '1600 lets me get the shutter speed I need'. Anyhow, however they get there, they now are at the ISO that they want to work. Then they centre the meter (maybe with some EC) to 'nail' the exposure, which means adjusting for some fixed output brightness at that ISO. To do that, they will almost always get a smaller exposure than they need. Supposing they decide that the DOF and motion blur are alright, they'll shoot, even though they might still have been alright up to half a stop more exposure. If they don't think they'll be alright, they'll raise the ISO (usually by a whole stop, I'd guess) and then centre the meter, and the same situation applies. Only when by co-incidence does the maximum exposure that their pictorial constraints allow is the same as the one that centres the meter at that ISO, will they have maximised the exposure, I don't think it often happens.

In any case, even if it does, the rigmarole that they have gone through to get there is a whole lot longer than the simple route, set the aperture and shutter for the largest exposure that your pictorial constraints allow, set the ISO to get the brightness, according to your usual methods for 'nailing the exposure brightness' (mine are do it at my leisure on a nice big computer screen).

I'm having a hard time understanding this argument. Is the basis of your argument that ISO often increments in whole stops while Shutter and Aperture increment in smaller steps? So if someone raises their ISO to get a fast enough shutter speed they might be underexposing by up to 2/3 of a stop?

That's part of the argument, but the nub of the argument is that if you pursue a different goal (getting the image brightness 'correct' vs maximising SNR) you will most likely end up a different place. The counter-argument that I'm being given is if you understand exposure as brightness and ISO as the 'noise control' you can still get the a maximum SNR position - certainly you can, because you have the controls that you have, but in all probability you won't.

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Bob

bobn2
bobn2 Forum Pro • Posts: 60,496
Re: Pls show examples where increasing brightness in post better than increasing ISO.

Andre Affleck wrote:

bobn2 wrote:

Andre Affleck wrote:

Andre Affleck wrote:

PhilPreston3072 wrote:

With the latest sensors, some have been proclaiming it's better to shoot at base ISO and increase brightness in post rather than increase ISO in camera.

I would like to see some examples of this. Are there any examples where increasing brightness in post delivers better IQ than increasing ISO in camera? And please, disable all NR settings.

bobn wrote here :

So, in the direct route, you would set the maximum exposure (subject to shake and the rest) and then set the brightening to match, whereas the other way you guess at the maximum exposure (via setting a guesstimate on the ISO dial). What most people will do, who don't know that it is exposure which matters, is centre the meter (or let the camera do it) and that will usually result in a lower exposure than had they set the maximum in the first place. No matter how you argue, that is how it really is. People using the ISO first technique will vary rarely set the maximum exposure

Not true, one starts raising ISO when they are already aperture and shutter limited.

Even so, it's unlikely that they will set the maximum exposure, simply because of what people think they have to do, and what they think their priorities. Somehow they will arrive at what they think is the right ISO for shooting, maybe by trial end error as you suggest and possibly just by making a guess, which is the impression that I get from people about setting ISO. You often get statements like '1600 lets me get the shutter speed I need'. Anyhow, however they get there, they now are at the ISO that they want to work. Then they centre the meter (maybe with some EC) to 'nail' the exposure, which means adjusting for some fixed output brightness at that ISO. To do that, they will almost always get a smaller exposure than they need. Supposing they decide that the DOF and motion blur are alright, they'll shoot, even though they might still have been alright up to half a stop more exposure. If they don't think they'll be alright, they'll raise the ISO (usually by a whole stop, I'd guess) and then centre the meter, and the same situation applies.

I think the reason why people are inclined to do what you suggest is because cameras are ergonomically designed that way.

Misuse of the word 'ergonomically' ;-).

They are not designed with exposure as a priority. This is probably another throw back from the film days.

Not so much a 'throwback'. Digital cameras were very expressly designed with a film-like user-interface.

One uses EC to fine tune exposure because it is intended to be used that way conveniently, and because the ISO control is buried in a menu somewhere. In addition, you can't simultaneously adjust ISO while watching the exposure meter. The cameras is almost forcing you to do the wrong thing by design.

Well, not making it easy, certainly. More easy on some than others. On my Nikon, I can see the ISO setting and the meter as I change ISO, on my Canon I can't. On the other hand, on my Nikon they've put the ISO button so it's very hard to adjust at eye-level, on my Canon its OK (but you can't see what you're doing)

I think it would be great if they allowed you to remap that dial to adjust ISO instead. Ultimately, ISO-less is the way to go, hopefully soon.

Yes, that would work well - with maybe a slight change in the meter presentation.

Only when by co-incidence does the maximum exposure that their pictorial constraints allow is the same as the one that centres the meter at that ISO, will they have maximised the exposure, I don't think it often happens.

In any case, even if it does, the rigmarole that they have gone through to get there is a whole lot longer than the simple route, set the aperture and shutter for the largest exposure that your pictorial constraints allow

Using what method to determine that maximum exposure? The camera meter is still tied to whatever ISO you are on and doesn't protect highlights well. If you rely on feedback from a histogram or preview, that too is tied to an even more arbitrary ISO. It would be nice if manufacturers would provide a raw histogram, but again cameras are not designed with these priorities in mind.

Well, the truth of the matter is that you only have to check the exposure when it's bright enough to max out the camera as a whole (that is base ISO) because you know it's max anyway. In dim light you'll probably be sacrificing DOF for light, but you already knew it was dim and made that trade in the first place, and set f/1.4. So, mostly the metering is checking highlights. The easy technique is to set 2 1/2 or a bit more stops of EC and spot meter off the highlights (if your camera lets you use EC in M). On most camera there are a few ISO settings to be working with, and you know those pretty well anyway.

So I'm still not convinced it is your exposure philosophy that is responsible for poor choices.

I got to the position I am by coming to the conclusion that it was, after looking at some of my own 'poor choices' and working through how and why I got there. I really don't think that the way I used to work was that unrepresentative of the general 'ISO first' method.

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Bob

bobn2
bobn2 Forum Pro • Posts: 60,496
Re: examples where increasing brightness in post is better than increasing ISO.
1

Andre Affleck wrote:

gollywop wrote:

PhilPreston3072 wrote:

gollywop wrote:

PhilPreston3072 wrote:

edu T wrote:

These after-brillig shots by Pierre Sottas with a D7000 are a classical example (AFAIK perhaps "the" one). This clear-cut "slain the jabberwocky and bring us its head" evidence was discussed here.

Captions by the author:

"A shot at ISO 6400, 1/30, f2.0 with very bad lightning conditions...

"...and the shot at ISO 100, 1/30, f2.0 (same exposure) and boosted 6 stops in RPP with highlights compression. No post-processing, EXIF should be intact."

(Can't help but notice that back then the angry mob of villagers wielding torches and forks was smaller and/or less frumious...)

I would say the ISO6400 has been disadvantaged here. The highlight areas of the verandah are already blown at this exposure. He should have reduced the exposure until those highlights weren't clipped at ISO6400 and then applied the same exposure settings for ISO100, and then applied shadow recovery if necessary.

They are the same exposure, and he got the shot he wanted. Reducing the exposure would simply give a shot a more noise. I would say ISO 6400 has a disadvantage, but it hasn't been disadvantaged.

You're missing the point here guys. The purpose of these shots was to compare the performance of ISO6400 with ISO100 pushed, it was not about obtaining best image quality. You can't properly compare ISO6400 with ISO100 by blowing out the verandah highlights and then attempt to recover the highlights when they were excluded in the first place.

If I was taking this shot and saw the verandah highlights blowing at ISO6400 I'd naturally lower the ISO until the highlights were no longer clipping. If the poster wanted to compare best image quality then this is what he should have done.

Well, not exactly missing the point since you didn't say "reduce ISO" to begin with; you said "reduce exposure." That's a rather different thing, and there certainly was no need to reduce exposure -- which is the point we guys were making.

Not to open any sore wounds, but it is interesting that the other poster still arrived at the correct settings to maintain highlights, even though he understood it as reducing exposure. Just sayin'

He didn't. Note above that he says 'ISO 100, 1/30, f2.0 (same exposure)'. He means same exposure as ISO 6400, 1/30, f2.0, which it is. The difference is, is at 6400, he's 'nailed' exposure, while at 6400 it's vastly improper, but much better.

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Bob

ultimitsu
ultimitsu Veteran Member • Posts: 6,650
Re: Pls show examples where increasing brightness in post better than increasing ISO.

bobn2 wrote:

So, mostly the metering is checking highlights. The easy technique is to set 2 1/2 or a bit more stops of EC and spot meter off the highlights (if your camera lets you use EC in M). On most camera there are a few ISO settings to be working with, and you know those pretty well anyway.

This sounds quite interesting, can you elaborate a bit on how it works? why 2.5 stops?

Andreas Stuebs Contributing Member • Posts: 924
Re: Pls show examples where increasing brightness in post better than increasing ISO.

Iliah Borg wrote:

I have to question as to how using the method somehow makes one think of ISO first. Its always the last result, after exposure is maximized, regardless of ones understanding of exposure.

The order depends on the understanding of the exposure. Most shooters I saw set ISO at some value before allowing the camera to use A, S, but mostly P.

I agree. I have come across "teachers" of photography actually advocating this approach. IMO this dates back to the old film approach, where you had first choose the film you are using and then for that roll, you were more or less stuck with that.

I am not that against using the "ISO" setting, but I do agree that you should only up the ISO setting when you hit the limits of what you can do with T or A (Mind you, most cameras give access to T and A more directly than the ISO setting and hence fine tuning is mostly done via either of these. Also a lot of textbooks suggest using the exposure time for bracketing)

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bobn2
bobn2 Forum Pro • Posts: 60,496
Re: Pls show examples where increasing brightness in post better than increasing ISO.
1

ultimitsu wrote:

bobn2 wrote:

So, mostly the metering is checking highlights. The easy technique is to set 2 1/2 or a bit more stops of EC and spot meter off the highlights (if your camera lets you use EC in M). On most camera there are a few ISO settings to be working with, and you know those pretty well anyway.

This sounds quite interesting, can you elaborate a bit on how it works? why 2.5 stops?

Your meter should be calibrated to centre when it gets 18% grey as the nominal exposure (10/ISO lux seconds). So, you need to miscalibrate it to regard 100% as nominal. According to ISO, the ratio of highlight to 18% is 78/10 = 7.8 = 2.96 stops (funny what these discussions can do - I see I miscalculated a long time ago, and have been giving my highlights a bit less than I could - dial in 3 stops). So, if the meter reads highlight and thinks it's 18% grey, it will give 3 stops less exposure than it should - so you correct that with EC, or recalibrating the meter (most will not let you recalibrate that far). In practice if you know how much headroom your camera has, you could dial in more than that.

(Just going back through my working, I realise where the extra half a stop came from, ISO leaves 1/2 stop for specular highlights over white - I must have taken it off somewhere along the line - 3 stops is better)

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Bob

Andreas Stuebs Contributing Member • Posts: 924
Re: Pls show examples where increasing brightness in post better than increasing ISO.

bobn2 wrote:

Andre Affleck wrote:

People using the ISO first technique will vary rarely set the maximum exposure

Not true, one starts raising ISO when they are already aperture and shutter limited.

Bob says - "people using ISO first technique".

Ok, then I have to question as to how using the method somehow makes one think of ISO first. Its always the last result, after exposure is maximized, regardless of ones understanding of exposure.

Interesting to do a poll, see whether most photographers set the ISO first or last. My guess is first, because the camera user interface is designed that way.

Will that poll actually be representative? Most people who write in this forum tend to know more about the mechanisms of digital photography than average.

I admit I have (at least) two modes of photography - in the snapshooting mode I even sometimes use the "IA" setting offered on my Panasonic. And in that mode I tend to set the ISO first, then try and get a reasonable DOF and keep an eye on the exposure time to avoid shutter speed. If I am in the more serious mode, I work differently.

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Andre Affleck Senior Member • Posts: 2,362
Re: examples where increasing brightness in post is better than increasing ISO.

bobn2 wrote:

Andre Affleck wrote:

gollywop wrote:

PhilPreston3072 wrote:

gollywop wrote:

PhilPreston3072 wrote:

edu T wrote:

These after-brillig shots by Pierre Sottas with a D7000 are a classical example (AFAIK perhaps "the" one). This clear-cut "slain the jabberwocky and bring us its head" evidence was discussed here.

Captions by the author:

"A shot at ISO 6400, 1/30, f2.0 with very bad lightning conditions...

"...and the shot at ISO 100, 1/30, f2.0 (same exposure) and boosted 6 stops in RPP with highlights compression. No post-processing, EXIF should be intact."

(Can't help but notice that back then the angry mob of villagers wielding torches and forks was smaller and/or less frumious...)

I would say the ISO6400 has been disadvantaged here. The highlight areas of the verandah are already blown at this exposure. He should have reduced the exposure until those highlights weren't clipped at ISO6400 and then applied the same exposure settings for ISO100, and then applied shadow recovery if necessary.

They are the same exposure, and he got the shot he wanted. Reducing the exposure would simply give a shot a more noise. I would say ISO 6400 has a disadvantage, but it hasn't been disadvantaged.

You're missing the point here guys. The purpose of these shots was to compare the performance of ISO6400 with ISO100 pushed, it was not about obtaining best image quality. You can't properly compare ISO6400 with ISO100 by blowing out the verandah highlights and then attempt to recover the highlights when they were excluded in the first place.

If I was taking this shot and saw the verandah highlights blowing at ISO6400 I'd naturally lower the ISO until the highlights were no longer clipping. If the poster wanted to compare best image quality then this is what he should have done.

Well, not exactly missing the point since you didn't say "reduce ISO" to begin with; you said "reduce exposure." That's a rather different thing, and there certainly was no need to reduce exposure -- which is the point we guys were making.

Not to open any sore wounds, but it is interesting that the other poster still arrived at the correct settings to maintain highlights, even though he understood it as reducing exposure. Just sayin'

He didn't. Note above that he says 'ISO 100, 1/30, f2.0 (same exposure)'. He means same exposure as ISO 6400, 1/30, f2.0, which it is. The difference is, is at 6400, he's 'nailed' exposure, while at 6400 it's vastly improper, but much better.

I meant the first response from PhilPreston3072. Its a bit convoluted, but he says:

He should have reduced the exposure until those highlights weren't clipped at ISO6400 and then applied the same exposure settings for ISO100, and then applied shadow recovery if necessary.

Andre Affleck Senior Member • Posts: 2,362
Re: Pls show examples where increasing brightness in post better than increasing ISO.

bobn2 wrote:

ultimitsu wrote:

bobn2 wrote:

So, mostly the metering is checking highlights. The easy technique is to set 2 1/2 or a bit more stops of EC and spot meter off the highlights (if your camera lets you use EC in M). On most camera there are a few ISO settings to be working with, and you know those pretty well anyway.

This sounds quite interesting, can you elaborate a bit on how it works? why 2.5 stops?

Your meter should be calibrated to centre when it gets 18% grey as the nominal exposure (10/ISO lux seconds).

I always thought it was 12.7% for digital meters. 18% was for film. That's why when you use an 18% grey card with digital you have to compensate a 1/2 stop.

Could that be your error?

rubank Senior Member • Posts: 1,082
The old funny "proof"

There have been numerous comments on how good the highlight rendering is in the ISO 100 shot (compared to the ISO 6400), and it is often cited as proof of the benefits of the ISO-less routine.

But I haven´t seen much of comments on the colour shifts and the ugly banding in the shadows in the ISO 100 shot.

Have the RAW files ever been published and "peer reviewed"? I might have missed that.

Jack Hogan Veteran Member • Posts: 6,941
Spot metering off brightest desired highlight

Andre Affleck wrote:

bobn2 wrote:

ultimitsu wrote:

bobn2 wrote:

So, mostly the metering is checking highlights. The easy technique is to set 2 1/2 or a bit more stops of EC and spot meter off the highlights (if your camera lets you use EC in M). On most camera there are a few ISO settings to be working with, and you know those pretty well anyway.

This sounds quite interesting, can you elaborate a bit on how it works? why 2.5 stops?

Your meter should be calibrated to centre when it gets 18% grey as the nominal exposure (10/ISO lux seconds).

I always thought it was 12.7% for digital meters. 18% was for film. That's why when you use an 18% grey card with digital you have to compensate a 1/2 stop.

Most Nikons (and I think Canons as well) place middel gray (L*50) in the raw data at quite a bit less than the recommended value, often less than 10% of full scale - try it.

Also keep in mind that 100% is supposed to be a perfectly diffusing white subject - which you practically never run into.  If you do landscapes there are often mixed reflected/diffused subjects above 100% that you may wish to retain some detail in. Ansel Adams, for instance, suggested in his Zone system that middle gray should be Zone V and saturation/specular highlights in Zone X, 5 stops above it.

I use the technique mentioned by Bob above (spot metering off the brightest highlight one wishes to retain detail in) quite frequently, and my biggest beef with Nikon is that the live in-OVF over/under exposure indicator maxes out at 2+ stops. I often would like to see when I am 3 stops or more over what the meter suggests.

Jack

bobn2
bobn2 Forum Pro • Posts: 60,496
Re: Pls show examples where increasing brightness in post better than increasing ISO.

Andreas Stuebs wrote:

bobn2 wrote:

Andre Affleck wrote:

People using the ISO first technique will vary rarely set the maximum exposure

Not true, one starts raising ISO when they are already aperture and shutter limited.

Bob says - "people using ISO first technique".

Ok, then I have to question as to how using the method somehow makes one think of ISO first. Its always the last result, after exposure is maximized, regardless of ones understanding of exposure.

Interesting to do a poll, see whether most photographers set the ISO first or last. My guess is first, because the camera user interface is designed that way.

Will that poll actually be representative? Most people who write in this forum tend to know more about the mechanisms of digital photography than average.

And people don't always give the real answer. There's a big tendency for people to give the answer they ought to give, and of course its a self selecting sample, and the questions need to be very carefully designed and all that stuff. Still, quite a few people here seem to be quite willing to pronounce on what most people do without an iota of evidence.

I admit I have (at least) two modes of photography - in the snapshooting mode I even sometimes use the "IA" setting offered on my Panasonic. And in that mode I tend to set the ISO first, then try and get a reasonable DOF and keep an eye on the exposure time to avoid shutter speed. If I am in the more serious mode, I work differently.

Which is all very reasonable. In fact, it would be silly to spend all this effort honing your technique to the n'th degree just to take snaps. Of course, what's galling is when the snaps turn out to be your best photos.

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Bob

bobn2
bobn2 Forum Pro • Posts: 60,496
Re: Pls show examples where increasing brightness in post better than increasing ISO.

Andre Affleck wrote:

bobn2 wrote:

ultimitsu wrote:

bobn2 wrote:

So, mostly the metering is checking highlights. The easy technique is to set 2 1/2 or a bit more stops of EC and spot meter off the highlights (if your camera lets you use EC in M). On most camera there are a few ISO settings to be working with, and you know those pretty well anyway.

This sounds quite interesting, can you elaborate a bit on how it works? why 2.5 stops?

Your meter should be calibrated to centre when it gets 18% grey as the nominal exposure (10/ISO lux seconds).

I always thought it was 12.7% for digital meters. 18% was for film. That's why when you use an 18% grey card with digital you have to compensate a 1/2 stop.

Could that be your error?

The Wikipedia page explains it all. Saturation based ISO is set such that 18% grey is 12.7 for an exposure of 78/ISO lux seconds. That makes saturation 1/2 stop above white, the reason being that there are things in the scene brighter than a white card. So, on SOS it should still be calibrated so that 18% grey is given by 10/ISO lux seconds exposure.

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Bob

bobn2
bobn2 Forum Pro • Posts: 60,496
Re: examples where increasing brightness in post is better than increasing ISO.

Andre Affleck wrote:

bobn2 wrote:

Andre Affleck wrote:

gollywop wrote:

PhilPreston3072 wrote:

gollywop wrote:

PhilPreston3072 wrote:

edu T wrote:

These after-brillig shots by Pierre Sottas with a D7000 are a classical example (AFAIK perhaps "the" one). This clear-cut "slain the jabberwocky and bring us its head" evidence was discussed here.

Captions by the author:

"A shot at ISO 6400, 1/30, f2.0 with very bad lightning conditions...

"...and the shot at ISO 100, 1/30, f2.0 (same exposure) and boosted 6 stops in RPP with highlights compression. No post-processing, EXIF should be intact."

(Can't help but notice that back then the angry mob of villagers wielding torches and forks was smaller and/or less frumious...)

I would say the ISO6400 has been disadvantaged here. The highlight areas of the verandah are already blown at this exposure. He should have reduced the exposure until those highlights weren't clipped at ISO6400 and then applied the same exposure settings for ISO100, and then applied shadow recovery if necessary.

They are the same exposure, and he got the shot he wanted. Reducing the exposure would simply give a shot a more noise. I would say ISO 6400 has a disadvantage, but it hasn't been disadvantaged.

You're missing the point here guys. The purpose of these shots was to compare the performance of ISO6400 with ISO100 pushed, it was not about obtaining best image quality. You can't properly compare ISO6400 with ISO100 by blowing out the verandah highlights and then attempt to recover the highlights when they were excluded in the first place.

If I was taking this shot and saw the verandah highlights blowing at ISO6400 I'd naturally lower the ISO until the highlights were no longer clipping. If the poster wanted to compare best image quality then this is what he should have done.

Well, not exactly missing the point since you didn't say "reduce ISO" to begin with; you said "reduce exposure." That's a rather different thing, and there certainly was no need to reduce exposure -- which is the point we guys were making.

Not to open any sore wounds, but it is interesting that the other poster still arrived at the correct settings to maintain highlights, even though he understood it as reducing exposure. Just sayin'

He didn't. Note above that he says 'ISO 100, 1/30, f2.0 (same exposure)'. He means same exposure as ISO 6400, 1/30, f2.0, which it is. The difference is, is at 6400, he's 'nailed' exposure, while at 6400 it's vastly improper, but much better.

I meant the first response from PhilPreston3072. Its a bit convoluted, but he says:

He should have reduced the exposure until those highlights weren't clipped at ISO6400 and then applied the same exposure settings for ISO100, and then applied shadow recovery if necessary.

Ah, well - that would have produced far from the same settings. The highlights seem to be about three stops above saturation for 1600, so he'd have reduced the exposure to say 1/250 at f/2.0 to protect the highlights at 1600, then he'd have switched to 100 and had three stops less exposure (and more noise) than Pierre did. What he should have done is what Pierre did, give it the longest exposure and widest aperture and shot at the optimum ISO for read noise (actually not quite, 200 is better than 100 on the D7000).

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Bob

David Rosser
David Rosser Veteran Member • Posts: 3,468
Re: Pls show examples where increasing brightness in post better than increasing ISO.

Andre Affleck wrote:

bobn2 wrote:

ultimitsu wrote:

bobn2 wrote:

So, mostly the metering is checking highlights. The easy technique is to set 2 1/2 or a bit more stops of EC and spot meter off the highlights (if your camera lets you use EC in M). On most camera there are a few ISO settings to be working with, and you know those pretty well anyway.

This sounds quite interesting, can you elaborate a bit on how it works? why 2.5 stops?

Your meter should be calibrated to centre when it gets 18% grey as the nominal exposure (10/ISO lux seconds).

I always thought it was 12.7% for digital meters. 18% was for film. That's why when you use an 18% grey card with digital you have to compensate a 1/2 stop.

Could that be your error?

12.7% as the standard pre-dates digital by many many years Thom Hogan explains it all in this article http://www.bythom.com/graycards.htmThe blame for 18% confusion can probably be placed at Ansel Adam's door.

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falconeyes
falconeyes Senior Member • Posts: 1,585
Examples
1

PhilPreston3072 wrote:

I would like to see some examples of this. Are there any examples where increasing brightness in post delivers better IQ than increasing ISO in camera?

There is a key in understanding this: input dynamic range. You will see VERY visibly better photographs shot at lower ISO and as there are plenty of them, there is no need to show one here.

But all of them must be of the kind where a large input dynamic range (larger than that at a higher ISO setting would allow you to capture) is compressed into the lower output dynamic range of a JPG or your display.

In practice, this means that shadow regions only have increased brightness in post.

If entire images have increased brightness in post then there will be no visible advantage in shooting low ISO (except where a post processor like LR5 includes a highlight preservation algorithm when adjusting exposure).

Once one understands this simple fact, there will be no reason for asking the question anymore.

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Jack Hogan Veteran Member • Posts: 6,941
Re: Pls show examples where increasing brightness in post better than increasing ISO.

David Rosser wrote:

12.7% as the standard pre-dates digital by many many years Thom Hogan explains it all in this article http://www.bythom.com/graycards.htm

That's not one of his clearest articles imho.  I believe point 2 (you would need a 12% card to get 'correct' exposure per ANSI without compensation) is actually quite misleading.

Jack

ultimitsu
ultimitsu Veteran Member • Posts: 6,650
Re: Examples

falconeyes wrote:

Once one understands this simple fact, there will be no reason for asking the question anymore.

And when one does not understand the simple fact, one persist that only seeing is believing. And even when presented with visual evidence, one can still find ways to mentally refute.

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