Auto ISO - Yay or Nay

[MReid]

Why make it harder than it has to be?

Why indeed? One of the things I think you might be over-looking is the fact that "perfect" exposure is not necessarily the right exposure. Just because your histogram is a perfect bell curve, does not mean that it's the ideal exposure for the scene.

If I want it darker or lighter than "perfect"...I adjust the exposure using the exposure compensation dial, up or down, takes a split second.

Common sense would make me think the auto Iso would then just compensate for the adjustment and the exposure wouldn't change but it does, so auto Iso must not compensate for adjustments via the exposure compensation dial.



I shoot d3 and d700 so am only speaking about Nikon pro grade cameras.
You mileage may vary on consumer grade camera, just saying don't poo-poo auto Iso until you have given it a try.

 

[KmH]

As Derrel points out, to a large degree it depends on the camera, in so far as both brand and grade level. In other words, don't expect entry-level grade cameras to perform auto functions as well as pro grade cameras.

Anyone recommending absolutes like 'always use Auto ISO' is giving bad advice.

 

[tirediron]

How well AUTO ISO works is dependent upon the implementation of the feature and the user's understanding and experience WITH using AUTO ISO. For many generations of cameras, Canon cameras had no AUTO ISO, and then a very primitive incarnation of it. As I understand it, the new 5D-III is the first Canon to come close to the Nikon implementation. Pentax has long had a superb AUTO ISO implementation. Nikon introduced AUTO ISO with the D70 back in 2004, and it has grown more and more capable. The thing that makes AUTO ISO more useful than ever before is the increasing use of slow, variable maximum aperture lenses among users who want to shoot run-n-gun style on family/candid/street/documentary/action subject matter; with slowish zoom lenses, one can EASILY "run out of f/stop" when a subject merely slips in to a shady spot. With a 70-300mm f/4.5~5.6 VR Nikkor for example, the maximum f/stop if f/5.6 at the longer focal lengths...if one spots a subject in a shaded area with that lens on the camera, the shutter speed can easily drop from 1/500 second in the sun to 1/8 second in a shaded doorway or on the "other side of the street"...there simply *is no other way* many times to gain shutter speed except by elevating the ISO.

If the camera has a capable AUTO ISO system, it makes sense to use it. But then again, one needs to know "how" to use it. With the rise of sow-speed consumer and pro-sumer level zoom lenses topping out as low as f/5.6 at maximum aperture, AUTO ISO has never made as much sense as it does today. And now that the better cameras allow shooting between ISO 100 and ISO 800 with almost no visible penalty, it makes more sense than ever. With the better FF cameras shooting well at up to and including 3,200, AUTO ISO has become another useful tool for those who have the smarts to actually understand how and when using it can offer a significant advantage.

Brilliantly said Derrel, as usual.

The key is: know WHEN and HOW to use it. Then it can be a tool to your advantage. I don't use it all the time, but when I do, I cap the auto ISO limit at a level of digital noise I'm comfortable with usually 800 or 1600.

Well said, and as I said in my first post, there are times to break "rules".

 

[Derrel]

Pentax has an interesting feature in some models, called TaV mode. It allows the user to select a desired Time value AND a desired Aperture value setting, and then the camera automatically selects the needed ISO value to make sure that the pre-selected aperture and shutter values lead to the correct exposure.

That would be a very useful exposure mode for fast shooting when subjects will move from sunlight to shade, or when a camera will be set up remotely, or for any situation where a SPECIFIC f/stop AND a SPECIFIC shutter speed are both needed. Let's say we have a 300mm f/4 lens and are shooting pictures from aboard a sport boat, and we are in moderate seas, so we need a shutter speed of 1/2500 second to prevent the motion of the boat and or engine vibrations from ruining all our shots. We want to shoot at f/4.5. The sun is playing peek-a-boo behind big,white,puffy clouds. There is plenty of fill lighting from the water, and so the lighting really is not all that high in contrast. The desired parameters are 1/2500 second for motion-stopping and vibration-stopping, AND we want shallow depth of field. TaV will always ensure that the right exposure is given at the desired shutter speed and f/stop--no matter whether the sun is out, partially out, or hidden behind clouds.

Let's say the situation is reversed, and we want to shoot with a 20mm lens, and shoot at the lens's absolute best f/stop, which happens to be f/11. We also want a high-ish shutter speed of 1/640 second so we can shoot quickly, one-handed actually, while hanging on to the tour bus handstrap. TaV will always make sure the camera gets the right exposure at f/11 and 1/640 second, no matter the light level.

A camera set up remotely might need f/5.6 and 1/500 second to ensure the right kind of photos can be captured. TaV will ensure that the needed speed and f/stop will be exposed correctly, across a wide range of times, from dawn to noon to dusk.

 

[sovietdoc]

Are you someone who can adjust their camera on the fly without looking at the controls? In otherwords, in a pitch-dark room, without removing your eye from the viewfinder, can you confidently manipulate all of the key exposure controls on your camera?

I might have misspoken somewhere, the problem isn't adjusting controls in the dark. The problem is spending too much time adjusting all the controls. So the question was is it okay to let camera like 5d3 set auto ISO for me so I don't have to worry about it. And with all posts in this thread being very helpful, I am leaning towards conclusion "yes, I can just use auto ISO" as long as I understand how it works, its limitations and how to use it properly without ruining my shots with worse color reproduction and noise.

Yes, I can set things like ISO/Aperture and Shutter speed blindfolded. Probably could do the same for AF modes, but manual point selection would be tricky. I could just press on the joystick to reset it and then move it left or right counting "clicks" but it's doable. Thankfully these cameras are built in such a way that you can easily adjust settings without looking at it. And in the dark, its got illuminated upper lcd and just the big lcd on the back that can help adjusting settings in the dark.

 

[tirediron]

...I might have misspoken somewhere, the problem isn't adjusting controls in the dark. The problem is spending too much time adjusting all the controls. ... Yes, I can set things like ISO/Aperture and Shutter speed blindfolded.

No, you didn't mis-speak; I was just wondering out loud.

 

[sovietdoc]

Oh okay. Well, the information provided to me in this thread was exactly what I was hoping for. Thank you all for discussing this.

 

[coastalconn]

I use auto-iso for wildlife/birds and it is an awesome (imho) tool on my D90. I set min shutter between 1/500th and 1/1000th depending on lighting and type of bird/environment. I set camera to base iso and max 1600 or 800 depending on settings. It allows me to shoot my tamron 200-500 handheld (although I've been using a monopod more often) and gives me one less thing to think about as some birds are fast. But for almost all other shooting I do not use auto-iso, but that's just me...

 

[Netskimmer]

I have been using it more recently, I don't see what the problem is with it. Most people wouldn't think twice about using shutter or aperture priority and those actually impact the artistic nature of the photo. Usually ISO should be set as low as possible while getting a proper exposure. (unless you want noise for some artistic reason)
I set my max to something safe like 800 or 1600 and the I choose the aperture and shutter to achieve the visual effects I want and let the camera bring up the ISO. If the scene is a little too light or dark I adjust with exposure compensation and if I find I'm shooting a scene that requires high ISO or is somehow tricky then I just switch to manual ISO. I have used it situations similar to what coastalconn described without any trouble.

 

[jaomul]

Someone said you can limit how high your ISO goes in auto, not all cameras allow this. In tv or av auto ISO gives you no idea what settings your camera will utilise. In fully manual auto ISO can be very handy. You want to keep your speed and aperture so a little noise might not matter for example when photographing a sports event

 

[Netskimmer]

Someone said you can limit how high your ISO goes in auto, not all cameras allow this. In tv or av auto ISO gives you no idea what settings your camera will utilise. In fully manual auto ISO can be very handy. You want to keep your speed and aperture so a little noise might not matter for example when photographing a sports event

Hmmm, I see your point on that. The D7000 lets me set a minimum shutter speed and maximum ISO. It also shows me what ISO it intends to use and recalculates it in real time as I change the shutter and/or aperture settings, this works in shutter and aperture mode as well as manual. If it did not do those things I could see not wanting to use it.

 

[jaomul]

The D7000 seems to have great custom functions. It is great you can set it up and keep it inside settings you will happily use but halo it a little tolerance to balance your shot if the might drops etc

 

[JClishe]

Anyone recommending absolutes like 'always use Auto ISO' is giving bad advice.

Same goes for people giving the opposite absolute advice like "never use Auto ISO". There is a time and a place for everything, it's up to the photographer to understand the options and make appropriate choices.

 

[Austin Greene]

I'm of the same mind as a few others here, but apparently not the majority. I always shoot full manual. Not because I think I'm a badass, but because I like to have complete control to get the exposure I want, which is not often what the camera wants. Even with my T3i's single dial, I have yet to encounter many situations where I haven't used manual. The only one I can think of is handheld hummingbird photography, where ill set my Aperture, crank the SS , and then let AISO finish off the exposure as I'm following the buggers around, but that is the only time I've used it.

 

[sovietdoc]

I agree that for most of the times manual is the way to go because it lets you adjust everything just the way you want, but in situations where you need to keep taking shots and you don't have much time to even rotate the dial (fast moving objects like birds for example), I think using a "semi-auto" configuration can be useful.

Someone said that in Av or Tv modes you have no idea what AISO does. I thought you can still set the maximum sealing limit for it and it will be capped at say 800 or 1600. Plus everytime you read exposure, it will display the ISO setting it wants to use in the viewfinder.