EOS high-end cameras seem to have a very high ISO range. According to some charts, the prosumer 6D has 102400 ISO extrapolated and the 1Dx can go up to 400K ISO. These numbers seem insanely high to me.

In the film era, if you wanted to maximize picture quality, you tended to stay close to 100 ISO or below. From all I read, this is still the case and ISO 100 gives the best digital capture quality.

I understand that now you can take pictures in near darkness that couldn’t be obtained a decade ago.

What I read in Is high ISO useful for photography? seems to confirm that it is useful in some situations but that it is better to stick to the base ISO resolution.

For regular use, what are the applications for high ISO shooting?

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    \$\begingroup\$ Why should they? You don't want it - you don't use it. I want it - I have possibility to use it. \$\endgroup\$
    – Zenit
    Sep 9, 2016 at 9:12
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    \$\begingroup\$ Next question: what is the point of variable aperture lenses? Every lens has a maximum sharpness at some aperture setting, if one "would want the best quality pictures you can get" you would never be far off that single aperture setting, right? \$\endgroup\$
    – null
    Sep 9, 2016 at 9:35
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    \$\begingroup\$ Canon might be rubbish at high ISO, other brands may be better. \$\endgroup\$
    – vclaw
    Sep 9, 2016 at 10:52
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    \$\begingroup\$ Stargazers-oriented? 1D is sports-oriented. It's the very exact opposite of a stargazer's camera: 1D is all about taking shots as fast as possible. Stars don't move that fast \$\endgroup\$
    – Agent_L
    Sep 9, 2016 at 13:36
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    \$\begingroup\$ The edit is much improved — but I think it's now a straight-up duplicate of Is high ISO useful for photography? \$\endgroup\$
    – mattdm
    Sep 15, 2016 at 11:50

4 Answers 4


What is the point of very high ISO capability?

To take pictures without as much light.

Just because a camera is capable of shooting at ISO 25600 (the actual ISO amplification limit of the EOS 6D) doesn't mean one has to shoot at ISO 25600, or even at ISO 6400. It's perfectly OK to use ISO 100 when that works. But as technology advances and we can get better and better pictures at higher and higher ISO settings it means there are photos we can now take that couldn't have been taken before. This especially true in darker settings where the subjects are in motion.

In the film era, except for very special project you tended to stay close to 100 ISO or beneath it to have quality pictures. From all I read this is still the case and ISO 100 gives the best digital capture quality. Even now, the higher ISO you go the worst it gets.

Kodak sold an awful lot of Tri-X, T-Max P3200, and Portra 100/400/800 back in the day. The same is true of Fuji and Superia X-tra 800 and Superia 1600. Fuji also sold a bit of FP-3000B. Ilford sold plenty of Delta 400, Delta 3200, XP2 Super, HP5 Plus, and Pan 400.

The main reason higher speed films have disappeared, even as some higher quality low speed films remain, is because digital cameras pretty much blow away any high speed film in terms of performance in low light shooting scenarios.

But then, if in most situations ISO 100 is better, why do camera manufacturers not restrict high ISO to specialties camera like the star gazers oriented 1Dx which can go up to 400K ISO.

First of all, the manufacturers attempt to provide what the market demands. It really costs very little to nothing more to allow higher ISO settings via software interpolations, which is what the highest H2 setting at ISO 204,800 on the EOS 1D X is. If saying a camera can shoot at ISO 204,800 will sell more units than saying it will only shoot up to ISO 51,200, which is the maximum hardware amplification of the 1D X, they're more than happy to give everyone an H2 setting.

The EOS 1D X, as well as its successor the EOS 1D X Mark II is hardly a "star gazers oriented" camera. It is a sports/reportage camera with a lot of other applications at which it excels.

  • \$\begingroup\$ "ISO 25600 (the actual ISO amplification limit of the EOS 6D" so are the real ISO 1/4 of the stated number? 750D states 25600 so really 6400, the 1300D states 12800 so really 3200; Sorry i am new to DSLR. i thought the 1dx was for astronomy or scientific use, but i understand the use for sport. for film speeds i know some used very fast film, in my "circle" though we used mostly 25 to 50 ISO and never above 200, and even then on very special occsions. \$\endgroup\$ Sep 9, 2016 at 10:22
  • \$\begingroup\$ It depends on the camera. With Canon digital camera some only have an "H1" setting which is twice the actual sensor amplification. Others have both an H1 and H2 setting where H2 is twice the H1 setting. If you look at the actual specs published by Canon it's fairly clear which is which. They'll list something such as "ISO Sensitivity: 100-51200 (in 1/3-stop or whole stop increments). ISO can be expanded to L: 50, H1 102400, H2 204800" \$\endgroup\$
    – Michael C
    Sep 9, 2016 at 10:40
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    \$\begingroup\$ @Reed "thought the 1dx was for astronomy or scientific use" more like photo journalism (AF, ISO) and sports (AF, ISO, fps), maybe studio work (connectivity). \$\endgroup\$
    – null
    Sep 9, 2016 at 10:42
  • \$\begingroup\$ @null photojournalism is just another word for reportage. It's all there in the last line of the answer. \$\endgroup\$
    – Michael C
    Sep 9, 2016 at 10:44
  • \$\begingroup\$ Yes, but the question came up in the comments nonetheless so I tried to address it again with my comment. Your answer is fine as it is. \$\endgroup\$
    – null
    Sep 9, 2016 at 11:06

The answer to this question is that you have taken a wide ranging collection of terms and taken a very narrow range of meanings for them. If you use the meanings that many people do then the question fades away.

Your individual assumptions would be considered invalid in most cases my many photographers and, taken as a whole, would be considered invalid by almost all photographers.


professional use, - which you seem to think relates to only non moving well lit images where absolute optical quality is the main benchmark. This is not the case.

for static subjects some are, many are not. Cameras which cater more for static subjects are available, but are not the most popular.

at normal light, You assume that normal is the equaivelnt of studio lighting or bright sunlight. It's not. "Normal" spans 2 to 3 standard deviations either side of the mean. That's anywhere from awfully bright to gloomily dark. Fortunately.

best quality pictures you can get, You assume that quality is measured in some "ideal" terms of advert bright, crisp well focused imagery. It's not.

so you shouldn’t veer far off 100 ISO. Most photos would suffer from this. And it becomes increasingly unnecessary as equipment improves.

(high iso is) useful mostly in special situations this would require MOST of the images that I take and many that most take to be taken in special situations. Less than ideal light. Camera moving. Subject moving. ...

it is better to stick to the base ISO resolution. only for above defined meanings of better.

if in most situations ISO 100 is better, In MOST, it's not. In some it is.

why do camera manufacturers not restrict high ISO to specialties camera - Because they wish to provide cameras that people want, that do things that people want them to do and that people will buy. And because they are not fascists or doctrinaire ideologues who wish to force their perceptions of how photography "should" be on others

For regular use, what’s the point of an insanely high ISO? Insanely high ISO is useful for obtaining images that nothing else is fast enough for. Regular use in that context is any use that requires insanely high ISO. Only a few cameras have this ability, so far, alas. eg Sony A7SII - Oh yes!!! (409,600 max ISO).

Here's an A7S review to go on with "only" up to ISO 102,400.

Driveby Shootings:

[One handed out the far side window, while (sssh) driving, ... ]

Short: The photo below was taken very much "on the fly" at ISO1600, 1/3200s. At eg ISO 100 it would have been approximately impossible to achieve.

Longer: The best camera to use is the one that you have with you.
I have taken to carrying a not-so-new Sony NEX5T in my jacket pocket. My larger dinosaur may or may not accompany me - either on a 'rapid-strap' or in a shoulder bag. But, the 5T in a pocket is able to be carried almost anywhere without being obvious. I usually carry it set to ISO 1600 - and can rapidly alter that if desired. For everyday use with an acceptable level of noise and general quality at less than "pixel peeping" resolutions ISO1600 is acceptable. To my surprise.

For "driveby shootings" it allows photos like this. Nothing marvellous BUT the photo below is about 40% of a frame. ISO 1600, f/7.10, 1/3200S. Insane. If I was taking that with time to frame it, adjust the ISO, adjust the aperture, and ensure that composition and more was OK, as was after top quality - then I'd certainly not have used ISO 1600 - and not have need 1/3200s. BUT his was taken [while driving? - surely not !?] (naughty naughty) from the right side of a right-hand-drive van across the passengers seat and through the passengers window, one handed at perhaps 50 kph. At ISO 100 - not a show. If that does not fall within the range of "normal" for the photos you want to take, that's fine. For some, it does.

enter image description here

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Sony NEX-5T, ISO 1600, f/7.10, 1/3200S. Driveby shooting.


Here's a report/review/love-fest on the king of insanity - the Sony A7SII

The Sony A7SII Review. The King of The Night gets updated. 24 pages (mainly photos) plus many reader comments. ISO 50 - 409,600.
Example image at ISO128,000 1/20s, f4 - noisy as!!!.
But it's an image. Under 0.2 lux if I've done my sums right* (quite possibly not) - but very dim indeed regardless. The eye could not see detail at that light level.

  • lux = 2.5 * 2^[(100 x f^2)/(ISO x t)]
    t = exposure in seconds.
    f = aperture eg 4 for f/4
    1 lux = bright moonlight
  • \$\begingroup\$ your individual assumptions would be considered invalid" Well that's why i am asking, i know i have strong opinions, formed on an "ideal" film'era Leika basis, but i am willing to learn the digital ways. The photo is nice but 1600 ISO while high is not insane, iso's of 100's K are. PS the Q on the restriction of ISO in Cameras is because i din't know how to ask the Q; manufacturers always want to add a lot of capabilities even if there are never used. \$\endgroup\$ Sep 9, 2016 at 10:08
  • \$\begingroup\$ Russell I saw your comment on the other Q. I asked this Q lostly because of insane seeming numbers of hundreds of thousands of ISO I was seeing, Michael Clark shed an explication, I also hadn't considered the triangle, in film since your ISO is predetermined, and I tended to always be at 100 or below, for me it was always only a linear range of aperture/speed, I never messed around with the ISO setting. I see that I will have to review, and renew, my ways. \$\endgroup\$ Sep 9, 2016 at 13:36
  • \$\begingroup\$ My friend claimed that 6000 ISO was ok, and your pic looks fine at 1600 ISO in this size. When does the noise becomes visible for a 300dpi print size? If the answer is already here on SE don’t bother answering, I’ll find it sooner or later. \$\endgroup\$ Sep 9, 2016 at 13:36
  • \$\begingroup\$ @Reed How high is acceptable very much depends on context. For a wedding I'd consider the quality of the NEX5T (used for the sample photo) was acceptable for general scene shots in good light at 1600 ISO. It would be getting more noisy than was nice for anything that wanted 'quality'and for expected wedding standard 800-400-200 ... depending on how close, how big, light level etc. BUT at 3200 it will often (to my initial surprise) produce images which Joe-Average does not notice are "somewhat noisy". \$\endgroup\$ Sep 9, 2016 at 13:49
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    \$\begingroup\$ @Reed Noise isn't a function of ISO. It is a function of the Signal-to-Noise Ratio. A well lit scene shot at ISO 3200 can be less noisy than a severely underexposed scene shot at ISO100. \$\endgroup\$
    – Michael C
    Sep 9, 2016 at 13:49

The availability of high ISO settings simply widens the classical triangle "ISO-aperture-exposure".

The obvious use is available-light photography; depending on your lens you quickly reach the limit of even ISO 1000 (about the end of the rope for film).

Even in not-so-bad light high ISO will be great for moving objects/action shots (moving camera!) because you can use shorter exposure, or large depth of focus/the ability to shoot without waiting for perfect autofocus because you can use a smaller aperture.

You also get away with cheaper, lighter lenses for similar pictures (sans bokeh). Weight may be important — prohibitive! — for even short trips (Canon Canon EF 200mm f/2.8L II USM: 0.8 kg; Canon EF 200mm f/2L IS USM: 2.5kg).1

1I'm not implying that the two lenses are totally comparable in all other respects — in fact, they are probably totally different lens designs —, but it's the two choices Canon offers for this focal length. And some of the different choices in the optical design may be motivated by the goal of a larger aperture without quality degradation.


Because many people like to do a bit of this and a bit of that. Why would you make a less versatile camera when you can make a more versatile one?

Pros may be able to afford separate bodies for studio and wildlife work (but shouldn't have to) and with their need for backup bodies that adds up to a lot of cameras. I knew someone who shoots weddings/portraits/wildlife/botanical professionally (some of these pay well, others are more interesting) so this is realistic.

As an amateur, who may only be able to afford one body, why should you be able to use it for everything. I've got a 40D (yes, I do keep cameras for quite a long time) which I bought for a safari (the interesting stuff happens at dawn/dusk) and other wildlife photography. I've also used it for:

  • Product photography/still life (with and without additional lighting, which was normally not photo-specific)
  • Stars
  • Landscapes
  • Portraits (mostly of the candid variety, family stuff, and kids move fast)
  • Sports (whitewater kayaking can need high shutter speeds but often takes place in the shade in winter).
  • Theatrical
  • Laser labs operating in near darkness

Nearly all of these often or sometimes have low-light/high speed situations; even with a fast IS lens you need a decent ISO. Of course I'm pretty limited compared to more recent models.

Further an amateur (and don't forget that this is a much larger market than pros) may not have the money/space for full-on studio lighting, so even if running a portable studio may need a stop or two more than someone who's doing it for a living.


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