Use ISO AUTO… Why Not?


I think I’ve gone through full-cycle with my preference for ISO settings on my camera. As a newbie, I primarily had the camera set to ISO AUTO because… well, it was just easier. As my skill level increased, so did my utilization of the camera controls. For some time now, I’ve been setting the ISO value manually while shooting in aperture priority mode. Manually keeping your ISO as low as possible is a great way to ensure high quality images, and I’m not disputing that it’s totally necessary with certain types of shooting.

But very recently, I went back to shooting ISO AUTO to evaluate the trade-offs between convenience and quality. What I found was that my camera limits the ISO value to 400 or lower when in AUTO mode. A comparison of an image shot with my camera at ISO 400 versus ISO 100 tells me that there are very subtle differences in quality, sometimes unrecognizable (especially with black and white conversions). But convenience alone isn’t the real reason I’ve gone back to ISO AUTO.

The camera sets itself to the lowest possible ISO value based on the lighting conditions — so with bright scenes, I’m still shooting at ISO 100. I also found that the camera won’t let the shutter speed fall below 1/60 seconds as long as it has enough room to bump the ISO value up to the next level. This is nice because it keeps me out of that 1/15 to 1/45 area, which most of us would still shoot at but is very prone to producing soft images. Another neat thing about ISO AUTO is that the camera will set the ISO value to things other than 100, 200, or 400. I noticed some of my low-light shots coming out at ISO 100, 125, 160, 200, 250, 320, and 400 — so it’s actually giving me a finer control over the exposure.

What do you guys think? Is ISO AUTO just for newbies, or is it actually useful for the skilled photographer too? I’m curious to hear how other cameras deal with ISO AUTO, so if you’ve messed around with it drop some insights into the comments.

28 thoughts on “Use ISO AUTO… Why Not?

  1. Janne

    I used to do everything manually at all times, like you. Lately, however, I’ve started using the “Super Program” on my Pentax K10: It sets all three parameters – iso, aperture and speed – to “optimal” values. You can choose what to optimize for; I’ve set it to stay at the current lenses’ “good” range of aperture (you can optimize for depth of field or speed as well). And you can set what range ISO to stay within (100-800 for me)

    But the great part of this mode is that at any moment, if I use the front dial it changes and lock the shutter speed; the front dial changes and locks the aperture; and front dial with mode button pressed changes and locks the ISO. A press on the “green button” on top will release the locks and return me to camera taking care of parameters again. So I effectively have aperture-priority, shutter priority, ISO priority and full manual available all at the same time.

    Often I don’t need to care and the camera gives me reasonable defaults. Whenever I do care, the settings are right there, just as if I already was in Aperture-priority mode (which is what I used to use).

  2. ramin

    I’m a control freak by nature and shoot practically always in either aperture-priority or manual mode. Which basically means that I also set the ISO manually also.

    While I’ve also noticed that the difference between ISO 100 and 400 is very small in most well-lit situations, I still want to control the setting. For me one of the main reasons is knowing what the camera is doing and learning a bit more myself. I always feel that the more automatic control I give the camera the harder it will for me to adapt to new circumstances.

    OTOH, I’ve also noticed that based on the available light and what I’ll be shooting, thinking and setting the ISO comes quite naturally to me by now and I don’t even think about it.

  3. Antoine Khater

    Brian what camera do you shoot with ? I am asking because the Canon 30D will only work in auto iso if you are in none creative modes (basic modes) so there is no option to use it in Av/Tv etc… where, IMHO, it would be most useful

    I seem to be locked on M mode and do not trust my camera’s judgment unless I really have to (shooting sports events etc…) and it is really hard for me to switch to automatic modes to have “limited” auto iso capabilites.

    Should there be AutoIso to go with Av or Tv then it would be a totally other issue for me

    Nick regarding the 400D auto iso problem sorry iI never heard of it

  4. Brian Auer Post author

    I shoot with a Konica Minolta Maxxum 7D — the very definition of complete camera controls. I didn’t realize that other cameras can’t use ISO AUTO in aperture/shutter priority or manual modes. If that were the case with my own camera, I’d still be using manual ISO settings too.

  5. Phil

    The Nikon D200 does this well – you can set the minimum shutter speed you want to go to and the max ISO. I tend to allow mine to go to 1600, even though it’s quite noisy at theat setting as I prefer a noisy picture that can be fixed in PP to a shaky one! I tend to leave the min shuter speed at 1/60 when using my 18-50 lens. My camera is usually in aperture priority when I’m walking around.

    I switch back to manual ISO when shooting off a tripod, or when using manual exposure.

  6. Simon Sant Cassia

    I use Auto ISO almost all the time when I’m outdoors. My Nikon allows me to set the max. ISO it’s allowed to go to, and the lowest shutter speed it will linger at before it bumps up the ISO. Just like yours it will also select finer ISO settings.

    Using this setting allows me to concentrate on the important parts of an exposure – shutter speed and aperture. Since ISO doesn’t do anything useful to image quality, I’d rather not have another thing to think about.

    Let’s say I’m in Aperture Priority. I want an aperture of f/8 but I don’t want my shutter speed to fall too low. So, without any intervention whatsoever, it’ll select ISO 640 (or whatever) just to make sure my shutter doesn’t fall below a certain level.

    However when I switch to M mode, sadly ISO AUTO stays on. I wish they’d turn it off automatically when I switch to fully manual mod.

  7. My Camera World

    Most of the time I have auto ISO turned off and set to the default setting of 100.

    There are certain situation, where I have to shoot or react quickly, normally in low light (concerts etc) and somewhat active motion where I may set my auto ISO setting, but I limit the maximum amount to either 400 for clean noise shots or 800 if I really need to go higher.

    But even the higher ISO at least for the D200 while noisy can but he use of Adobe Capture RAW limit the amount of colour noise and approach those high IOS B&W film images.

    I really use ‘P’rogram mode and will either use ‘A’aperture or ‘S’hutter priorty depending on whether DOF or Motion is an important criteria.

    Niels Henriksen

  8. JS Nature Photos

    I normally always shoot with manual ISO. I don’t have that great of a camera, and at higher ISOs there is some noticeable softening. Also, with optical image stabilization I can almost always handhold down to around a 1/8, and I have a feeling that left to its own devices the camera would up the ISO way before that.


  9. Neil Creek

    Unfortunately, auto ISO is not a feature of my camera, the Canon 350D. I can imagine it would be very handy in a number of situations, and I’m saddened it’s not available. I know it’ll be on whatever camera I get next, however :)

  10. My Camera World

    I really need to check what I am writing before I post and not be so fast.
    My apologies to everyone.


    But even with the higher ISO at least for the D200, while noisy, can be used with Adobe Capture RAW to limit the amount of colour noise and approach in appearance those high IOS B&W film images.

    I rarely use Program mode….


  11. Jenni

    My old Canon 350D didn’t have an Auto ISO option, so I’m only now trying it with my Canon EOS 40D and I really like it even though I have the feeling that it’s setting it too high sometimes. Most pictures I took in Vienna have a ISO of 400 while I think some of them were in bright enough conditions to use something below that, but I’ll have to keep an eye on that in the future to really form an opinion.

    My main reason for using Auto ISO right now is that every time I changed my ISO value for my old camera I forgot to change it back, so I have a whole lot of pictures that were taken at 800 or 1600 even though they could have been shot at 200 or so.

  12. libeco

    I have my camera set to 100 ISO. Rarely I will take it up to 200, but higher never. I only use M, no other program modes. I don’t really know for what kind of picture higher ISO settings will work without creating too much noise, but I feel leaving it at the lowest possible gives me one less parameter to think about…

  13. Damien Franco

    When shooting weddings I would often use Auto ISO to be able to react quickly. I rarely came out with images that were less than satisfactory. One note, however, is that when photographing a wedding my clients were in fact receiving a wedding book and not large prints. In all other situtuations I have my camera on Manual.

  14. Luis Cruz

    Unfortunately, I don’t have an auto-ISO mode on my camera. I usually set everything manually, and occasionally shoot in aperture priority mode.

  15. the_wolf_brigade

    In terms of digital cameras, I only own a super zoom, or “bridge camera” (Fuji Finepix s6500fd). While it may be the best in terms of noise reduction in it’s class, higher ISO’s, ie. above 400, tend to give pretty bad results. I like to maintain control over the ISO so as to avoid this.

    Thankfully I normally have my Joby Gorillapod handy whenever the ISO goes above what I would consider acceptable for the situation. Occasionally there may be times such as family snaps where even a mini tripod is not practical, though here capturing the moment is a small trade off for a noisy image that might need a bit of retouching.

    I suspect this may be a very specific DSLR tip, and even then, from the responses above, it depends on the manufacturer.

    Still, as with all tips, they give us things to think about and try out to see whether they will suit us as well. While this tip may not be applicable to me, it gives me something to keep in mind if I ever decide to migrate to a DSLR.

  16. Ryan

    Yeah, not available on the Canon 400D when in Av/Tv/M modes. You’d think it would be a simple feature to add via a firmware update. My guess is that it’s a marketing decision to only make the feature available to higher priced models. I would definitely try it out if it were available to me.

  17. Al Morrison

    Like Jenni’s comment above, I recently went from a Canon 300D to a 40D and find that the Auto ISO, while seeming to peg higher than I would set it manually, does a pretty good job. For a while I was worried that the higher setting might lead to a noise problem, but the 40D has impressed me with its ability to deliver excellent image quality even when I’ve manually pumped up the ISO to 1600. Also had the same problem as Jenni in forgetting to reset the ISO on the 300D and lost a lot of shots that called for a different value. Right now I’m leaving it on Auto ISO and not having any problems.

  18. Brian R

    I shoot almost exclusively in Manual mode. I used to use Program much like Janne describes (I’ve also got the K10D), but I found that the camera frequently optimized the wrong way due to factors outside it’s knowledge.

    For instance, I might be in an awkward stance and hence be willing to go for a higher ISO in exchange for a faster shutter. But the camera doesn’t know, so it does the opposite, and I end up with a soft, ISO100 shot. Or vice versa — I’ve got a solid rest, so maybe I’m willing to go to a 1/8s shutter, but instead I get 1/60 and ISO800.

    Maybe I just tend to shoot in odd circumstances. Regardless, I got tired of fighting the camera and just went to manual.

  19. Music Site

    my wife has a good quality camera, I just forgot what kind it is, but I will check and let you know later, we took a lot of pictures with it, but it was hard for me to use the auto thing, as I said I am not expert or something, but I am trying to learn cause we usually go out on many vacations and I would like to have them memorized,

    I just have a question for you: what do you think of printing the pictures online through Kodak? I never tried it before but I am thinking of it, they have a website and all I can do is submitting my pictures and then they print them and send them to me, do you think it would have good quality?

    Thank you and good luck,
    Have a nice day.

  20. Jeff O'Hara

    I use auto iso 90% of the time on my Nikon D40. There are a few situations when I turn it off.

    1. When my flash is on.
    2. When on a tripod.
    3. When i have a very bright backlight.

    Auto iso is definately not only for newbies. If I didn’t have auto-iso on all the time I would miss a lot of shots I would not otherwise have gotten.


  21. Andreas Manessinger

    On my Nikons I use it all the time. It simply works, and even while I used the D200 with its higher noise levels, I had always set maximum ISO to 1600 and minimum shutter speed to a value appropriate for the lens (stabilized or not, focal length) and the situation (action or not). I think that in many situations my images were still less noisy than they would have been on a Canon 5D. Why?

    Because when you don’t have or use the feature, you don’t evaluate light shot by shot, you evaluate locations and situations, and then you set ISO to the maximum you are likely to need. Light, on the other hand, changes shot by shot, and a small difference in angles can make for a big difference in available light. Without the automatics I would shoot many images on higher ISO than needed, and thus I would end up with effectively more noise.

    Now, on the D300, I have max ISO routinely on 3200, and occasionally, like during my recent Jazz concert shoot, I even go to 6400. There is no reason to not do it. If I can’t hold the shot at lower ISO, then I don’t get it at all. If the camera thinks 6400 is appropriate, then it is always such a situation. The shot at 6400 may be usable or not, I may have to turn it to B&W, but at least I have a shot.

    It depends on what you do. If your concept is one of noise-free fine art photos, then you restrict yourself to certain kinds of photos and willingly accept to not being able to take others. That’s OK, but it is not my thing. If I can get the shot, I do it. If I throw it away later, salvage it with special noise reduction programs or live with the noise creatively (I have even added more noise in Photoshop at occasions), at least I have all the options.


  22. CyberCarsten

    I enjoy Auto ISO for more than a year now – my point ofview is very similar to Andreas’. It is a 3rd variable in low-light and street photography. Just a great feature to have (and to turn off from time to time).

  23. Samuel Kordik

    As a professional shooting a wide range of subjects, I’ve found the Auto ISO on my Nikon D200 to be invaluable. Shooting in rapidly changing conditions, going in and out of shade, the Auto ISO feature removes one variable that I have to think about. I set the minimum shutter speed based on the lens I am using and the maximum ISO based on lighting and on desired image quality—most of the time, it is set to ISO 800. The camera does a beautiful job of preserving sharp shutter speeds and pulling out the lowest noise possible. In fact, I find that it does exactly what I would do; but it saves me from having to take the time to do it.
    I do set the ISO to manual, however, when shooting landscapes or still lifes (where I am using a tripod and want to maximize image quality) and when shooting with manual strobes/flashes (because the Auto ISO and TTL metering can’t accurately expose with these). In these instances, I am almost always using a handheld meter anyway and setting exposure manually.
    One note…on the D200, there is a “Recent Settings” menu that lists all of the recent menu settings. My Auto ISO menu setting is always there near the top, so I can quickly change it if I change lenses or shooting situations.

  24. Mike

    Similar to Samuel Kordik above, I use auto iso quite a bit, in conjunction with the auto bracketing on my D200. It is not a sign of “newbieness” as I have been shooting for almost 25 years, over 15 of those as a professional as well. The sign of a “newbie” is someone who is overly concerned with seeming “newbie,” if that makes sense. Most amateurs would be surprised to find out that many professionals eagerly use as many auto features as possible because it enables them to “get the shot” as quickly as possible, which in turn saves them time, money and prevents unnecessary navel-gazing in front of a monitor. If this wasn’t true, you wouldn’t see professionals using VR or IS lenses, auto-focus, or even digital cameras.

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