New member question: Auto ISO

[RustBeltRaw]

It's worth mentioning that high-ISO advocates tend to be full-frame, high-end DSLR users. A D4, a 1DX, or a 5D mkIII will have wildly different characteristics than lower-end cameras, so this is one case where I think Colin's advice needs a little qualification.

If you have a choice between nothing and a noisy shot, then as Colin said, send your ISO to the sky if you have to. But inevitably, you'll get a useless or web-only image much quicker with lower-end cameras. Personally, I'll only push my 60D past ISO2000 if I know I'm not printing or using the shot for my portfolio. On my camera, and in my opinion, ISO2500 and above starts to really crush details. But it also depends on how well-lit your subject is. I could give a crap about noise in the background... but I don't. Just one more element focusing the viewer's attention on the subject.

I wonder why setting Auto ISO doesn't enable the exposure compensation slider in manual mode. I suspect I'm missing something (though the manual gives no clarification), because it seems like settings my 60D for manual and Auto ISO forces one to stick with whatever exposure level the camera's metering system picks (+/-0EV).

[Colin Southern]

It's worth mentioning that high-ISO advocates tend to be full-frame, high-end DSLR users. A D4, a 1DX, or a 5D mkIII will have wildly different characteristics than lower-end cameras, so this is one case where I think Colin's advice needs a little qualification.

If you have a choice between nothing and a noisy shot, then as Colin said, send your ISO to the sky if you have to. But inevitably, you'll get a useless or web-only image much quicker with lower-end cameras. Personally, I'll only push my 60D past ISO2000 if I know I'm not printing or using the shot for my portfolio. On my camera, and in my opinion, ISO2500 and above starts to really crush details. But it also depends on how well-lit your subject is. I could give a crap about noise in the background... but I don't. Just one more element focusing the viewer's attention on the subject.

All true, but ...

- for a given generation of sensor technology, noise is proportional to sensor size anyway. Possibly this is the ONE thing that the average consumer doesn't realise when they ask the question "why buy an SLR when I have a great camera phone); both can take great shots in good light, but as the light levels drop, the camera phone quickly starts to founder. So it's not so much a question of "how high an ISO can you go to with a crop-factor camera before the noise becomes excessive" as it is "all things considered, how low does the light level need to drop before the crop-factor camera can't do the job, no matter what you do".

- When people say things like "I'll only push my 60D past ISO2000 if I know I'm not printing or using the shot for my portfolio", again, I ask "if you're not going to go past 2000 then what other variable are you going to change to balance the exposure for a failure-is-not-an-option shot"?

[Manfred M]

All true, but ...

- for a given generation of sensor technology, noise is proportional to sensor size anyway. Possibly this is the ONE thing that the average consumer doesn't realise when they ask the question "why buy an SLR when I have a great camera phone); both can take great shots in good light, but as the light levels drop, the camera phone quickly starts to founder. So it's not so much a question of "how high an ISO can you go to with a crop-factor camera before the noise becomes excessive" as it is "all things considered, how low does the light level need to drop before the crop-factor camera can't do the job, no matter what you do".

- When people say things like "I'll only push my 60D past ISO2000 if I know I'm not printing or using the shot for my portfolio", again, I ask "if you're not going to go past 2000 then what other variable are you going to change to balance the exposure for a failure-is-not-an-option shot"?

True; but the average user of a camera phone or P&S shot doesn't notice is the very heavy handed noise reduction algorithms that some camera manufacturers use to "eliminate" noise. The image looks fine on the screen; but when you enlarge and look at the pixel smearing from the heavy handed noise reduction; your 12MP image has the same resolution as a 4MP camera. Panasonic's Venus II processor was (in)famous for this.

[Black Pearl]

If you have to capture a shot and you've ran out of other possibilities what are you going to do if you refuse to use higher ISO's than you are comfortable with?

Yes there will be a reduction in resolution.
Yes there will be a reduction in dynamic range.
Yes there will have a limited range of final output option.

But you still have to take the shot.

I suppose this is where amateur and professional photographers start to differ. An amateur may only take pictures in ideal conditions and if they are outside of their comfort zone or won't give pixel level perfect images they don't take a shot, which is fine thats not a criticism. Amateurs take pictures for themselves and the only people they have to please is themselves. A professional though will get into situations where they have to take a shot no matter what. They can't choose not to. They can't tell a client that they don't like using high ISO's because the results won't match an 'ideal' that they have logged in their noggins. They can't come back another weekends when the conditions are better. They can't only take pixel level noiseless, histogram perfect, rock steady, prime lensed masterpieces, they have to take a picture no matter what.

[RustBeltRaw]

Personally, I'll only push my 60D past ISO2000 if I know I'm not printing or using the shot for my portfolio. On my camera, and in my opinion, ISO2500 and above starts to really crush details.

I should rephrase this. No ISO2500+ image from my 60D has had sufficient quality to make my portfolio. Details are crushed to the point that the image can only be viewed small, with multiple sharpening techniques. I still push past 2500 on a pretty regular basis, but I'm mentally screaming for a higher noise threshold the whole time. This fact has made me pretty good at hand-holding fairly lengthy exposures, which is great for landscapes and such, but not so much for action. It's only the combination of low light and action that forces me past 2500.

So regardless of a camera's performance, I still agree with Colin. If ISO is the difference between any shot and no shot, go high. If I hadn't, I wouldn't have grabbed this ISO3200 (with remote flash) shot.

[Colin Southern]

I should rephrase this. No ISO2500+ image from my 60D has had sufficient quality to make my portfolio. Details are crushed to the point that the image can only be viewed small, with multiple sharpening techniques. I still push past 2500 on a pretty regular basis, but I'm mentally screaming for a higher noise threshold the whole time. This fact has made me pretty good at hand-holding fairly lengthy exposures, which is great for landscapes and such, but not so much for action. It's only the combination of low light and action that forces me past 2500.

So regardless of a camera's performance, I still agree with Colin. If ISO is the difference between any shot and no shot, go high. If I hadn't, I wouldn't have grabbed this ISO3200 (with remote flash) shot.

Here's a similar one for me - shot at F1.2 - ISO 3200 (Max for that camera) - 1/20th ...



Absolutely ZERO chance of slowing the shutter anymore (it's a plane doing around 100 KIAS) - lens won't go any wider than F1.2.

[LocalHero1953]

Can I add another option to the mix - pushing exposure in post (Lightroom or Photoshop)?

Essentially, using high ISO is an amplification process that boosts your signal, but also boosts noise. You can do the same amplification in post, where you have more control of which parts of the image you boost.

I use a Leica M9, which has notoriously weak high ISO performance above 800. Some kind soul (I can chase up the reference if needed) has compared using high ISO vs adjustment in post, and concluded that, for the M9, beyond 640 you get less noise by boosting in post than increasing ISO. In other words, the S/N ratio increases excessively above 640 - boosting the 640 image allows you to exploit the lower S/N ratio. Other cameras would have different thresholds.

In my own trials I find this works as long as (a) I do not push it more than 2 stops in post, equivalent to using ISO 2500 instead of the actual ISO 640, and (b) the images have reasonable contrast with most of the interest in the lighter parts, so the noisier shadows can be held back.

A downside of this approach for amateurs who chimp (professionals don't chimp, right?) is that the image on the screen is too dark to review properly.

[jcuknz]

The difference between the box camera and the Leica [ie IIIc] was the range of situations it could cope with except today with suitable precautions the cellphone is much more capable than the box brownie and the good camera is also more versatile.. For many purposes the cellphone meets the user's needs which is why I think the day of the P&S is coming to an end.

Watching a professional at my son's wedding last year he seemed to chimp almost every shot where I rely on a one second review and thats that. Must play the very devil with battery life.

Deliberate under-exposure works best I think if the end result is B&W judging from a photo I saw some years back when DSLRs went to only three figure speeds. I see it as a viable alternative to a camera shake/ subject movement spoilt shots and have frequently been rubbished by 'experts' with their heads in the photo sand for suggesting it.[ NOT on CiC ] They all suggest getting a DSLR with a fast lens ... LOL ... for a Mum taking daughter's dancing ... they must be joking.
Even free download Paint.Net has Levels adjustment as one of its features.

But I am bordering on my belief that there is too much attention given to technical matters and not enough to the concept of an interesting photo. ideally one has both but the shot is the most important. If it is a good shot it deserves a place in the portfolio irrespective.

[dje]

I use a Leica M9, which has notoriously weak high ISO performance above 800. Some kind soul (I can chase up the reference if needed) has compared using high ISO vs adjustment in post, and concluded that, for the M9, beyond 640 you get less noise by boosting in post than increasing ISO. In other words, the S/N ratio increases excessively above 640 - boosting the 640 image allows you to exploit the lower S/N ratio. Other cameras would have different thresholds.

Hi Paul

I would be interested to see that reference if it's not too much trouble thanks.

I've read a very informative set of articles by Emil Martinec of the University of Chicago in which he explains why it is better to increase the ISO setting than increase the exposure in pp for the lower ISO values. However beyond a certain value of ISO, he explains that there is no real benefit from a noise point of view. The basic reason comes down to the source of the main noise contributions. Some noise is introduced before the ISO amplifier and some after (A/D converter). For many cameras, at low ISO, the dominant noise is that introduced after the ISO amp. This noise is not increased by increased gain in the amp but is amplified if exposure increase is done in software. As the gain of the ISO amp is increased, the noise introduced before it (and at it's input) is amplified and at a certain point, it becomes the dominant noise source. Once you get above this ISO point, the noise gets amplified by roughly the same amount with extra ISO or extra software gain.

All of the above is based on shooting raw. If shooting jpeg, things like in-camera noise reduction would need to be considered I suppose.

Dave

[LocalHero1953]

Dave, I got the information from this thread on the Leica users' group forum, where it was discussed ad infinitem.
http://www.l-camera-forum.com/leica-...way-shoot.html

[dje]

Dave, I got the information from this thread on the Leica users' group forum, where it was discussed ad infinitem.
http://www.l-camera-forum.com/leica-...way-shoot.html

Thanks Paul, I'll have a look.

Dave

[Sponge]

Can I add another option to the mix - pushing exposure in post (Lightroom or Photoshop)?

Essentially, using high ISO is an amplification process that boosts your signal, but also boosts noise. You can do the same amplification in post, where you have more control of which parts of the image you boost.

I use a Leica M9, which has notoriously weak high ISO performance above 800. Some kind soul (I can chase up the reference if needed) has compared using high ISO vs adjustment in post, and concluded that, for the M9, beyond 640 you get less noise by boosting in post than increasing ISO. In other words, the S/N ratio increases excessively above 640 - boosting the 640 image allows you to exploit the lower S/N ratio. Other cameras would have different thresholds.

In my own trials I find this works as long as (a) I do not push it more than 2 stops in post, equivalent to using ISO 2500 instead of the actual ISO 640, and (b) the images have reasonable contrast with most of the interest in the lighter parts, so the noisier shadows can be held back.

A downside of this approach for amateurs who chimp (professionals don't chimp, right?) is that the image on the screen is too dark to review properly.

I recently read a thread that was suggesting the same thing about my camera (Olympus OM-D E-M5). The noise results were the same between a properly exposed shot using ISO 3200 and an underexposed shot using ISO 400 and then pushed 3 stops in Lightroom. Apparently anything above ISO 400 on my camera offers almost no improved noise performance over pushing in post while losing dynamic range. Even knowing this I have a really hard time decidedly underexposing an image instead of bumping the ISO and I'll have to test it out the next time I really have to push the ISO.

http://www.mu-43.com/f42/pushing-iso-om-d-50027/