using auto-ISO

John Desjarlais

Hi all,

I posted this earlier in the nature & wildlife forum, and somebody suggested I repost here (please forgive the duplicate posts). As my first real de-lurk I thought I'd ask if anybody else has been using auto-ISO in their shooting. I started using it about 2 months ago, and I will say that my percentage of usable shots has gone up dramatically. My basic strategy is to use it in aperture-priority mode when tripod shooting still subjects, and in shutter-speed priority mode when handholding and/or shooting moving subjects (flying birds, my kids, etc.). The way it works (on my D70) is as follows:

AP mode - you set the slowest allowed shutter speed before ISO increases (I use 1/125 since I've had some mirror slap issues on my D70). For example, if I'm set at f5.6 in AP mode and 1/125 is 1/2 stop underexposed, the ISO will automatically reset to 400 from 200. On the other hand, if 1/250 is perfectly exposed, the ISO will stay at 200.

SP mode - camera will adjust to the widest possible aperture before ISO increases. I'll typically use 1/500 in SP. For example, if I'm at 1/500 in SP, and the widest aperture on my lens (say 4.0) is still 1/2 stop underexposed, then the ISO will automatically adjust to 400 from 200.

In manual exposure mode, I think ISO adjusts to set exposure as needed.

All this is based on the philosophy that a sharp grainy shot is preferable to a noise-free but motion blurred shot (unless of course that's the intended effect).

happy shooting,

gluwater

John Desjarlais wrote:

Hi all,

I posted this earlier in the nature & wildlife forum, and somebody suggested I repost here (please forgive the duplicate posts). As my first real de-lurk I thought I'd ask if anybody else has been using auto-ISO in their shooting. I started using it about 2 months ago, and I will say that my percentage of usable shots has gone up dramatically. My basic strategy is to use it in aperture-priority mode when tripod shooting still subjects, and in shutter-speed priority mode when handholding and/or shooting moving subjects (flying birds, my kids, etc.). The way it works (on my D70) is as follows:

AP mode - you set the slowest allowed shutter speed before ISO increases (I use 1/125 since I've had some mirror slap issues on my D70). For example, if I'm set at f5.6 in AP mode and 1/125 is 1/2 stop underexposed, the ISO will automatically reset to 400 from 200. On the other hand, if 1/250 is perfectly exposed, the ISO will stay at 200.

SP mode - camera will adjust to the widest possible aperture before ISO increases. I'll typically use 1/500 in SP. For example, if I'm at 1/500 in SP, and the widest aperture on my lens (say 4.0) is still 1/2 stop underexposed, then the ISO will automatically adjust to 400 from 200.

In manual exposure mode, I think ISO adjusts to set exposure as needed.

All this is based on the philosophy that a sharp grainy shot is preferable to a noise-free but motion blurred shot (unless of course that's the intended effect).

happy shooting,

Bump

I don't know anything about Auto ISO but I do agree with your statement about a noisy sharp shot rather than a clean blurred shot. I would say if you are happy with your results than keep on doing what works for you. Anyone else have any thoughts on this?

John Desjarlais

gluwater wrote:

Bump

I don't know anything about Auto ISO but I do agree with your statement about a noisy sharp shot rather than a clean blurred shot. I would say if you are happy with your results than keep on doing what works for you. Anyone else have any thoughts on this?

Thanks for the bump, Nick. My post was feeling rather lonely!

Nikolai

John,
I'm not a pro/expert, but I haven't been using Auto ISO since I got an opportunity to control it (Sony 828 long time ago:-). And I definitely want to control it manually with my dSLR (currently Canon 30D).
I usually keep it at the lowest level (ISO100 in my case). If I see that I don't get enough shutter speed I increase it manually, since it's a very fast/easy process. Once light comes back I set it back to 100.
I don't see any problem/crime to have it on auto, but something inside me just does not let me do it for myself
However, if it works for you - that's great, keep using it.
HTH (and welcome to Dgrin!)

Mr. 2H2O

John,
I use a P&S so I have this debate raging inside me almost every week. I shoot sometimes in really tough lighting so my tiny sensor has to struggle. I did a lot of test shots to find out my camera's algorithm for ISO on auto plus I tested a lot for how shaky I get in different situations (quick shot, or spend time to set up, or tripod, etc.). In my personal experience, I go for faster shutter speed and higher ISO. For me, I need to shoot faster than 1/60 in the dark so I go for 1/125 wide open (F2.0 for me) and let the ISO go with auto. I have closely compared shots with manual settings and this technique and for me, I found that even when my camera goes out to ISO3200 at 1/125 I get better shots to work with than 1/400 at 1/30. I use NeatImage and GIMP to bring them back to pleasing my eye and I use smart sharpening technique to get detail back after NeatImage.

My camera is Sony F717 so it works for me but your camera may have a different algorithm for determining auto ISO. Sometimes I get into a dim room and my camera shocks me with a nice shutter speed on program mode - gotta love that lightning fast Zeiss!

Mike