Auto ISO

Vertigo

Vertigo

Vertigo

Soldato
Joined
28 Dec 2003
Posts
16,497
So, do you use it?

Whilst my 7D had an Auto ISO feature, it was pretty basic and I never really bothered using it, preferring to control the ISO myself.

Now, with the 5D3, the feature is far more flexible and so I've been giving it a bash and I've found it quite useful.

What I didn't realise at first is how the automatic shutter speed setting works. Whilst you can set the minimum shutter speed to a specific value, if you leave it on automatic, it actually obeys the 1/focal-length rule of thumb, keeping the speed above this value, even when using a zoom and changing focal lengths.

This means that, when using aperture priority, I can dial in the aperture I want and leave the camera to choose the shutter speed and ISO, using the slowest shutter speed it deems appropriate for the focal length and then setting the ISO accordingly. I can then dial in whatever exposure compensation I need.

Another option which didn't occur to me at first is to use it when in manual mode, setting both the aperture and shutter speed and then allowing the camera to choose the ISO. This provides another type of automatic metering mode, although obviously within limits as if your shutter speed is too high and/or aperture too narrow then it won't be able to lower the ISO enough to expose properly.

The one downside to this mode is that no exposure compensation is possible. As I routinely find myself using between 2/3rds and a full stop of compensation, this means the manual mode doesn't generally expose how I want with Auto ISO enabled so I've left that alone for now.

Just thought I'd share my observations and wondered if anyone else is using it or has experimented with it?
 
I almost always use auto ISO. I use it in aperture & shutter priority.
The only time I don't is if I'm in manual mode (if you need exact control of exposure it's pointless to use auto ISO). This is usually when a flash is involved.

With that said, I can set the min/max shutter and ISO speeds within the auto ISO settings which helps and I can still use exposure compensation in aperture or shutter priority with auto ISO. But I rarely touch it as my camera's AF point meter on what I'm taking a picture of.
 
I've recently started playing with it as well. Basically since I got my latest body a D7000. I had the D90 before that and it was useless at anything above 800. I've stuck the D7000 to max ISO of 3200 and min shutter of 1/80th and have to say I'm getting far more keepers.

It very rarely goes anywhere close to 3200 but even if it does it's still usable. And at least the images tend to be nice and sharp.

I don't use it all the time but it's handy to lean on when just taking quick snaps.
 
I use it most of the time. My X-Pro 1 can produce great images all the way to 6400 so I just set auto ISO 200-6400 and set my minimum shutter to 1/100 and let the camera do the work.
 
I don't tend to, but only because I tend to be out and about so just set and ISO for the location and roll with it.

However with my D7100 I'm happy to use it quite high.

You mention that on the 5D3 it obeys the focal length rule for the shutter speed, do you know if it compensates for having IS on the lens? I have no idea if my D7100 does any of this so should probably look! Also for the DX users among us, I wonder if it compensates accordingly for the crop factor.

At the end of the day, getting the picture grainy is better than not getting it at all.
 
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I use it all the time in gig photography. Last night I was covering a new open mic night in the area and it's invaluable. Setting it to a max of 2500 allows me to just concentrate on the scene. As the night went on I had to make one change to it to bump it to 3200. Even on the 5Dmk3 it will always try to use the higher setting for faster shutter speeds, which isn't always what you need. Limiting it allows you know what you'll get and when you'll have to switch to manual if it's not letting you grab a specific look.

It's a very handy feature to have. You can easily do without it, but it just makes things that little bit easier at times :)
 
With my D90 I used it with prime lenses because it didn't vary the speed with the focal length. With my new D800 it is on most of the time for regular shooting and the event I did a few weeks back. When I'm doing landscape with it then auto ISO is off and I shoot at ISO 100. The D800 implementation is very good although I would prefer slightly more control over the shutter speed with respect to focal length you can shoot 1/FL but I prefer to go little faster to increase the odds, the next setting is 1/2*FL, which at ISO < 1600 is fine but at higher ISO I wouldn't mind dropping down to a 1/1.5*FL and at ISO 3200 o more going to 1/FL. The D800 is fantastic at ISO 6400 but it is still nice to stop thing going too far over ISO 3200 if you can.
Would also be nice if you could program different lenses with a different rule. Small light primes are easier to hold at 1/FL but heavier lenses like 70-200mm f/2.8 definitely helps to have 1/1.5*FL with my hands.
 
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DBT85 said:
You mention that on the 5D3 it obeys the focal length rule for the shutter speed, do you know if it compensates for having IS on the lens?
Click to expand...

No it doesn't but then that makes sense as IS only helps with static subjects and the camera has no way of knowing if you're shooting a moving target :)
 
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