PHOTO Q&A – Auto ISO
Brendan Coles (www.brendansphotogallery.com) wrote:
I was wondering what your opinion is regarding Auto ISO. Do you recommend manually setting your ISO or just leaving the camera on Auto ISO and let the camera decide which ISO to use?
Hi Brendan, if you’re talking about most point and shoot, and consumer level DSLR’s the answer is – I suggest that you manually set your ISO. Think of ISO as a third exposure control. You have shutter speed, aperture and ISO – all working together to help you get the right ISO.
Most cameras provide the best photo quality at a low ISO. If you get into a situation where the Auto ISO thinks it’s too dark, rather than open up the aperture, the Auto ISO may decide to crank up the ISO – inducing noise.
I could give other examples, but you should get the point. If you seek to be anything more than a snapshooter, learning how to properly set the ISO is a good idea.
There are a few exceptions to this rule. Owners of the new Canon 5 MK II, Nikon D3 and D700, as well as a few other high-end models have access to a different kind of Auto ISO. This more sophisticated ISO allows the photographer to set a constant shutter speed and aperture and then adjusts the ISO to match. This is very valuable, and I hope this feature finds its way to low end cameras soon. I wrote about this as one of the reasons I like the D3 in a post you can find in our TWIPPHOTO.COM archive. Here’s the salient passage in that post…
“Here’s a typical scenario for me. I photograph lots of flying birds. They don’t always cooperate with the light. I might start shooting a bird in direct sunlight, only to have it fly out of the light into shadow, and then back into the light. The result might be a four or five stop difference in light on the subject. It’s impossible to change the ISO on the fly, while trying to capture the bird in flight and in focus. But using Nikon’s Auto ISO, I just set my shutter speed to 1/1000th of a second and my aperture at f/5.6 then the auto ISO adjusts automatically for the lighting condition.”
I hope this answers your question. While I can’t answer everyone’s question on the blog, I still welcome them. They help me formulate an opinion about the things I cover here. And who knows, I might just pick your question to post for the world to see. Send them to twipphoto@gmail.com.
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All Pentax DSLRs have an auto-iso function that works in all modes but M, which adjusts ISO and the other exposure variable(s). I hardly use it.
The K10D and K20D also have a ‘TAv’ mode on the dial, that, as Scott describes, allows you to fix shutter speed and aperture, and the body adjusts ISO based on lighting. I use this mode a lot when shooting indoors, low light, without a flash. I open up the aperture as wide as possible, then set the shutter speed to the lowest possible for the situation. ISO is then adjusted automatically.
TAv, and similar modes in the other brands, can really make life a lot easier in certain circumstances.
One of the reasons I chose my K-M 5d is it’s Auto ISO mode, which varies between 100-400 ISO as it feels the need (not unlike the Nikon mode you describe, in fact). 100 and 200 are basically identical, and 400 is so close as to make no difference. So if your camera limits the range of its auto to the high quality levels (which can be as high as 1600 ISO or more on some newer DSLRs, and as low as 100 on some digital cameras), then I’d say it’s a useful tool, especially as a default mode so you have more chance of catching an unexpected opportunity.
Thanks Ben I didn’t know the Pentax had that mode. It does sound useful.
I’ve found using Auto ISO invaluable even on my older Nikon D70 camera. I think you have to understand when to use it and when to turn it off. I wish I could cap the upper limit like you can the lower limit. I don’t know if that’s available on the newer cameras but it’s a feature I would like to see someday.
I’m looking forward to the day we don’t have to worry about iso and we can just focus on the creative results. We’re almost there although I suspect once we have a useable iso range from 50 to 256000, the next question will be in camera HDR – selecting level of shadow detail and level of highlight detail. By the time that whole paradigm shift finishes we’ll be on to holographics. :)
I love the Auto ISO feature on my D80. Alas, it isn’t nearly as flexible as what you describe on the D3/700. It limits the minimum shutter speed to 1/125s.
Still, coupled with shooting in Manual or Aperture Priority, it effectively gives you a new mode – Exposure Priority.
Hi i have a Nikon D40 in the menu of auto iso u can set the value that u want to be the max iso and the value of the longest shutterspeed u want the auto-iso to use (so for example i set it on 1/60 shutterspeed and iso 1600 than he will only increase the iso to maximum 1600 when your shutterspeed should get below 1/60)
It works great so if u have the same option u should use it.
Sorry about the bad writing, i’m Belgian and don’t have to much time.
Not just the D3 and D700. Pretty much all Nikons from the D70 up the range have the excellent auto-ISO system. I find it very useful on my D80.
Regards,
Rob…
I have the Nikon D80, and there is a setting when you’re shooting in Aperture Priority, Shutter Priority, etc… that allows you to set the lowest shutter speed, and then set the highest ISO that you’re willing to go to if that shutter speed is reached. I know I should know how to properly set the shutter/ISO, but I find this a valuable tool whenever I get to a situation where I don’t have time to play with the camera settings.
Thanks Rob I probably should have said “mid to high end” cameras.
Camera manufacturers are slowly catching up with the fact that with digital cameras it’s as easy to change ISO from exposure to exposure as it is to change aperture/shutter speed. The evolution from the days of film, with its fixed speed, is simmering along slowly.
I would like to see the equivalence of ISO/shutter/aperture as the 3 ways to control exposure to be reflected more explicitly in camera controls and exposure modes. We might then emerge blinking fully into the sunlight of the digital age.
My suggestion is this: We scrap conventional exposure modes altogether. You click the “P” button to get Program mode where everything is auto. You can then fix any one out of ISO/shutter/aperture just by clicking on the relevant button and moving a thumb-wheel. The other two elements of exposure control remain under auto control.
You can then override a second element out of ISO/shutter/aperture and the remaining one is left on auto, under camera control. You can keep overriding any of ISO/shutter/aperture as suits your needs. The camera takes account of the last two elements you overrode and sets the remaining one on auto for you.
At any point you press “P” and start again.
The whole thing is natural and intuitive and gets away from complex and confusing exposure modes with daft names.
It also fits in with the idea of giving attention to what matters most in any situation. You are free to fiddle around with aperture if you are bothered about sharpness, depth of field and controlling lens aberrations, with shutter speed if you are bothered about freezing action or eliminating camera shake, and ISO if you are bothered about colour saturation and controlling noise. You can concentrate on those aspects which are important to you for that shot and the camera takes care of the exposure. It’s a dream.
Come on Canon, Nikon and the rest. Time to change the paradigm.
Thanks Scott. I’m actually shooting with a Nikon D80. A agree that its nice that you can put a lower limit for the shutter speed, which is great for shooting in aperture priority. It would be really nice though if you could set limits for aperture size if shooting shutter priority.
When I first moved from a point and shoot to the D80 I wanted to learn everything, so I only ever shot in manual mode, with manually setting the white balance and ISO. Now I’m hearing that a lot of pros like to use Aperture priority a lot, so I’m basically trying to figure out what settings I should be controlling, and which settings the camera is smart enough to control. Your response has been a great help.
Thanks again for answering my question.
Hi all,
Thanks for the post I hadn’t thought about using Auto ISO in this way.
I have a Nikon D90 and in the Auto ISO settings you set the minimum shutter speed, after which the ISO will be automatically raised, I generally use Aperture priority mode so so thought this was the only way it worked. However, in Manual mode you can set both the shutter speed and aperture with the main and sub dials, but instead of getting a meter, the ISO is adjusted to give correct exposure. Exposure compensation can then be used under difficult lighting.
Works great, and thanks for the tip!
I like knowing that my D3 can do the Auto-ISO shift and have talked with other sports photographers who used it effectively when shooting a football field that half in direct sunlight and half in the shade of the stadium. The good high-ISO performance of the D3 lets you get away with that for editorial photos.
Personally, I am enough of a control freak for my work that I don’t use the Auto-ISO (yet). My greatest fear is turning it on and then forgetting it is on when I move out of the shooting situation that requires the agile ISO settings. When I am dealing with difficult lighting conditions, I want to exhaust all of my other options for getting reasonable light BEFORE I start turning up the sensitivity of the camera. It keeps me thinking about how to be a good photographer rather than letting the camera do all my thinking.
Now, a lot of work is done at ISO 3200/6400 or even higher sometimes. I can see benefit of being agile between, say, ISO 200 and ISO 800 on the D3 when you want to preserve a specific depth of field (fixed aperture) and maybe a certain background illumination effect (fixed shutter). I guess I have been doing it so long without Auto-ISO, I just know to go to the sensitivity settings on my own rather than letting the camera do it.
Put me in the dinosaur category of not using it — although I don’t begrudge anyone’s desire to use it for their work. In the end, is the client happy with the results?
-Mike
@Scott , not only mid-high end, also d40-d40x and d60 have it.
LOL well that’s what I deserve for not having any experience with the low-end cameras. Does it work exactly like it does on the D3? If so, this is an amazing feature for a low-end camera.
I know my 40d has auto ISO, but I’ve always been afraid to use it. I shoot weddings, and I get in a cold sweat thinking about shooting away in a dark church and finding out I was at 1600 the whole time without knowing it!
I’ve been shooting with a 40D and have been using Auto-ISO. Somebody correct me if I’m wrong but I believe the auto ISO mode on this body will automatically set the ISO speed from 100 upto 800 in order to maintain the correct exposure, however the aperture and shutter speed have a higher priority.
i.e. if shooting in Manual mode, you set the Aperture and Shutter yourself and the Auto-ISO adjusts itself to maintain exposure. If shooting in Aperture Priority, from my experience the body sets a reasonable shutter speed and increases ISO speed upto 800, if the image is still underexposing it then decreases the shutter speed further.
Regarding the D40/x/60′s… I think it works the same but I’ve not used a D3. On my D40x, I can set a maximum ISO allowed before auto ISO will give up and start slowing down my shutter speed and a minimum shutter speed at which the auto ISO should start increasing. The ISO I set becomes the baseline and it will increase from there up to the maximum allowed before it starts to slow the shutter speed down below my defined threshhold.
I use it with great success, particularly in aperture priority mode for low light shots with a fast prime lens. I can choose a wide aperture that still has enough depth of field for my subject and a desireable ISO while allowing the ISO to increase when I get down to my slowest handholdable shutter speeds.
Just wanted to make sure Olympus isn’t being left out of the Auto ISO love… All Olympus DSLRs have an Auto ISO setting, and you can select the high-end limit of the range it uses.
I’ve been shooting an Olympus E-510 for about a year, and its Auto range is from 100 to 400 (selectable). Its last-generation image processor starts showing a little bit of noise at 800, so the engineers smartly limited the auto to 400.
The newer processor handles noise better, and I believe the range can be limited all the way up to the useable range (i.e., 1600 on the E-420). Keep in mind that this is what I’m gleaning from the descriptions I read on the web… I haven’t had my hands on one of the E-x20s yet.
Anyway, it certainly is a useful feature, and it’s available on some very affordable cameras (with the legendary Olympus lens quality, to boot).
My Nikon D200 has Auto-ISO but I barely use it, since most of my photos are shot at ISO 100 (for iStock quality purposes). For personal stuff I go higher, sometimes using Auto-ISO, but it would be great to have a better light-sensitive camera so I don’t cringe every time my ISO creeps up past 400! ;)
wouldn’t know i don’t have a d3 but it works like this: in auto iso in the menu u can change max sensitivity: 400/800/1600, and u can min shutterspeed: 1/125 to 1 second.
So if your meter read that it goes below the min shutterspeed it increases the iso to the maximum u choose.
I don’t think the question should be: “is Auto-Iso better than setting the ISO manually?” but rather “what is better in *this* situation?”.
There are situations in which the auto-function is great – like Scott pointed out. There are situations in which a manual setting for best quality is better. Knowing what the camera can achieve and how to set that is one important step towards that.
And the other? Remembering which settings you used when you last used the camera aka checking the camera *before* use and *during* use. And yup… I got the pictures with ISO 1600 in bright midday light or the ISO 100 with 1/5 s exposure in a church before I finally learned that lesson. Learned it mostly… got to remind myself… from time to time.
Newer Nikon cameras have auto-ISO that lets them set a min. shutter speed and a max ISO ceiling. All older ones have auto-ISO, but no ceiling save the camera’s max. My old D50 was this way, but the D300 lets you fine-tune the ISO range.
IIRC, Canon also has auto-ISO, but you can only go between 100-800 ISO, even if the camera can go far above that? I only have experience with a Digital Rebel, XTi, and a 40D, though.
I know that this is extremely subjective, but what would a recommended min. shutter speeds for auto ISO be? Camera default? Subject dependant?
I would advise that you thoroughly get to know your auto ISO on your camera before you use it in action. I made a mistake of setting up my auto ISO on my D300 just before shooting my brother’s wedding. I noticed the ISO setting sometimes ‘stuck’ at 1600 when going from inside to outside in bright conditions making the picture a little noisy.
James
Freiburg, Germany
The auto-ISO on the Nikon D80 works like so. You set a minimum shutter speed and a maximum ISO. In aperture priority mode, the camera will attempt to expose the image using the ordered settings (Aperture, ISO). However, if the proper exposure requires a shutter speed slower than minimum shutter speed then it bumps the ISO. Nevertheless, this capability is hobbled by a very small range of possible minimum settings. The minimum shutter speed can only be set to between 1s and 1/125s. Hence, I’ve been burned several times when using Auto-ISO in this mode. In manual exposure mode, the camera will fix the f-stop and shutter speed and control the exposure only with the ISO up to the maximum ISO setting. However, the ISO capabilities (ISO 100-3200) of the camera are less than a D700 or D3 so the usefulness of the feature is also similarly limited.
On the Canon 5DmkII Auto ISO functionality, it is limited to 3200 and does not go higher, which is too bad. Second, it isn’t as useful as the Nikon version in that you cannot set a minimum shutter speed, rather it chooses the minimum handholdable shutter speed based on the focal length. This is at once a very smart feature, since it KNOWS what lens you have attached, but it pre-supposes that you hare taking photos of static subjects. Taking pics of people moving about at 1/50 (or lower!) isn’t usually a recipe for success. You can use Tv mode to lock a shutter speed in, but it doesn’t allow it to go higher in favorable light. In essence, Canon knew it needed Auto ISO but didn’t understand all the ways people would want to use it. If you’re taking static shots, it’s pretty cool and thinks for you, so long as you don’t need higher than 3200. In my case, that’s often a stop too little.
I should add too that in Manual mode, Auto ISO means 400. That’s it. Hope you like 400!
I have a Nikon D40 and I normally use the Auto ISO function. For general shooting I limit the maximum ISO to 1600, however for portraits I turn off the Auto ISO function and set to the ISO to 200.
I totally agree – I think at least among prosumer-grade bodies, there should be two “priority” dials. Full manual will keep shutter, aperture, and ISO under manual control as it does today. First Priority can be any of the three and will behave similar to Av/Tv modes today, but also have you set a secondary priority, allowing you to lock in any of the two and adjust the third to match your preferred exposure. For example: P1 ISO100, P2 f/4 will adjust your shutter speed (maybe for ambient-light portraits); P1 1/500s P2 Auto will work like Tv 1/500 ISO Auto today (as I’d expect it to work, at least); P1 f/5.6 P2 1/250s will work similar to Auto ISO as Scott describes it in the main post.
You’ve nailed it – ISO *is* our third exposure variable, and it’s time that digital camera manufacturers truly embrace it! I would much rather have set-two-auto-third priority settings instead of the Auto:Portrait, Auto:Landscape, Auto:DoF settings that are geared towards amateurs anyways. Give me Auto/P, S, A, I, SA, SI, AI, M on the dial! With how good high-ISO performance is on today’s bodies, there’s NO reason not to have it that way.
How can I set up the Canon 5DmkII for AutoISO as mentioned in the article?
Try Page 58 of the manual. if you can’t lay your hands on it try this link.