Sporgon said:
ahh ofc, that would explain why I only saw a benefit on a specific scene. This would also mean that native vs non-native iso is relevant to consider if practicing ETTR?
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ahh ofc, that would explain why I only saw a benefit on a specific scene. This would also mean that native vs non-native iso is relevant to consider if practicing ETTR?
eyeland said:
Good point.
The answer is yes, because if you exposed to the right by say two thirds whilst in (L) you would actually be over exposing by one and two thirds EV.
Some have suggested that if you're shooting in RAW then ISO 50 (L) is pointless because you can just shoot ISO 100 and over expose by one full EV (stop), and then post process down. I disagree as if you do this you are lumbered with all your files showing one EV over exposure. IMO much better to shoot in L, gain from the benefit of ETTR, and allow the camera program to bring files back to 'correct' exposure, but you have within there the better info for darker areas.
The caveat of course is that just as when practicing ETTR, when shooting in (L) the photographer must judge the strength of highlights because you will be further over exposing them.
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Fully understood and agreed.
By "non native ISO" I was however also referring to ISO values such as 160 and 320, as these are pulled (similar to 50?) in contrast to eg. 125 which is claimed to be pushed.
I am trying to figure out if the inclusion of pulled ISO values make ETTR less useful
By "non native ISO" I was however also referring to ISO values such as 160 and 320, as these are pulled (similar to 50?) in contrast to eg. 125 which is claimed to be pushed.
I am trying to figure out if the inclusion of pulled ISO values make ETTR less useful
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eyeland said:
Sorry, I read your response as just relating to 'L' and 'H'; perhaps that's because I know about those !
I am not so sure of my facts with intermediate ISOs, but from what I do know, again you raise a very valid point.
If ISO 160 is pulled from 200, ie it is just ISO 200 over exposed by one third of a stop and reduced back to 'correct' exposure in camera, then the same principle will apply. Conversely if 125 is pushed one third from 100 the principle applies in reverse: you'd be already under exposing by one third so ETTR would have to be increased to compensate.
By the same principle ISO 160 would then have one third less EV latitude ( the dreaded DR ) than 200, but the test graphs don't show this.
But I am not sure of my facts on these 'non native' ISOs. I've read that people claim there is less noise at ISO 160 than 100, but I have not found this to be the case. However I have found that ISO 50 (L) can give smoother data than 100.
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Sporgon said:
I've not noticed a marked difference between 100 and 160, but this chart is worth a look.
http://home.comcast.net/~NikonD70/Charts/RN_ADU.htm#EOS%205D%20Mark%20II_14
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neuroanatomist said:
Yep, it's interesting how relatively flat the 1Dx is before about 1600ISO.
The idea that intermediate isos are pushed or pulled makes a little more sense to me than something at the amp level ("The shape of the curve can tell you something about the amplifier circuitry of the camera"), but I wonder why they'd take a completely different approach with the 1Dx.
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It is ETTR. Unless you blow the highlights (and with a "normal" DR scene, there is plenty of highlight room), you get about 1 step lower noise. This means smoother tonal gradations, better response to more extreme pp, WB tweaks, vignetting corrections, etc. In critical situations, I would take a shot at ISO 100 as well, just in case.
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I see lots of confusion here.
Except for the EXIF flag indicating exposure, the RAW file you'll get with ISO50 @ f/8 @ 1/400 will be exactly the same as the one you'll get at ISO100 @ f/8 @ 1/400. The only difference is that, if the camera's meter tells you that the proper exposure is ISO100 @ f/8 @ 1/400, it'll tell you that you should be exposing the ISO50 shot at f/8 @ 1/200. And, of course, the RAW developers are programmed to invisibly apply a stop of digital pull to the ISO50 shot.
There will be a difference between ISO50 @ f/8 @ 1/200 and ISO100 @ f/8 @ 1/400 -- and it's that difference that people almost always compare.
BUT!
There won't be a difference between ISO50 @ f/8 @ 1/200 and ISO100 @ f/8 @ 1/200.
And, of course, there will be a difference in the RAW files between ISO100 @ f/8 @ 1/400 and ISO200 @ f/8 @ 1/400.
Hope that helps clear things up....
Cheers,
b&
P.S. A very similar thing happens with highlight tone priority, except in the opposite direction. The RAW files for a given shutter and aperture will be identical between ISO100 and ISO200 + HTP, but the meter will be different. b&
Except for the EXIF flag indicating exposure, the RAW file you'll get with ISO50 @ f/8 @ 1/400 will be exactly the same as the one you'll get at ISO100 @ f/8 @ 1/400. The only difference is that, if the camera's meter tells you that the proper exposure is ISO100 @ f/8 @ 1/400, it'll tell you that you should be exposing the ISO50 shot at f/8 @ 1/200. And, of course, the RAW developers are programmed to invisibly apply a stop of digital pull to the ISO50 shot.
There will be a difference between ISO50 @ f/8 @ 1/200 and ISO100 @ f/8 @ 1/400 -- and it's that difference that people almost always compare.
BUT!
There won't be a difference between ISO50 @ f/8 @ 1/200 and ISO100 @ f/8 @ 1/200.
And, of course, there will be a difference in the RAW files between ISO100 @ f/8 @ 1/400 and ISO200 @ f/8 @ 1/400.
Hope that helps clear things up....
Cheers,
b&
P.S. A very similar thing happens with highlight tone priority, except in the opposite direction. The RAW files for a given shutter and aperture will be identical between ISO100 and ISO200 + HTP, but the meter will be different. b&
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TrumpetPower! said:
So basically you're saying the ISO50 setting only affects metering, not sensitivity?
If I set up at ISO100, meter dead center, take a photo, and then drop to ISO50 with all else being equal, I'll see the meter move one stop to the left, but the actual picture will be the same?
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3kramd5 said:
Metering and the ISO value recorded in the metadata. Assuming you're in manual mode (since in an AE mode, the change from ISO 100 to ISO 50 will result in a compensatory change in aperture or shutter speed to maintain metered exposure), the RAW data file will be the same - an ISO 100 exposure. The jpg file will be pulled down a stop, and when you open the ISO 50 RAW file in an editor, it will display darker than the ISO 100 file, because the RAW editor/converter will pull the exposure down based on the ISO value in the metadata.
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3kramd5 said:
By George, I think he's got it!
Yes. If you ignore the meter, two exposures at the same shutter and aperture but with the one at ISO50 and the other at ISO100 will be identical save for the metadata (and therefore subsequent default processing). So, if you shoot manual and RAW, ISO50 is pointless.
But for those who use autoexposure, and especially for those who shoot JPEG, it can be a very handy tool to have in the toolchest as a quick way to get the benefits of ETTR (at, of course the expense of a stop of headroom) either straight out of the camera or with fewer steps in post-processing.
Cheers,
b&
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neuroanatomist said:
And, to follow up on neuro's point, because I know somebody will wonder and / or ask...yes, they're equally useless for knowledgeable photographers shooting RAW in manual mode, but they can be useful for those shooting in an autoexposure mode and especially useful for JPEG shooters.
The utility for JPEG shooters is especially pertinent because the 5DIII has such an awesome onboard RAW processor.
If you shoot JPEG in low light, you'd be a bit silly to not enable the H modes. If you shoot RAW and manually expose, there's no point to them.
Cheers,
b&
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