Using Auto ISO in Manual Mode

[MikeHarris7]

Hi all,

I recently discovered a kind of cool trick. It depends on the camera you have somewhat and what features it has, but this is kinda cool. If you need a certain shutter speed and aperture and you're in a dynamic environment (say a wedding) where you can't stop and analyze each shot, you can set your camera in manual mode with auto ISO turned on. The camera will automatically adjust the film speed to get a proper exposure. I've found that, all things considered, sharpness is more important than noise - to me anyway. Also, I use the D700 which gets really clean images up to 3200 ISO. For a wedding what I'll do is set my base ISO at 640 (which means it will try to use that first - I do this because it saves my flash batteries through the end of the night vs shooting at say 200 ISO). I typically shoot a 28-75mm 2.8 lens, so I'll set the minimum shutter speet to 1/100th of a second and set the max ISO to 3200. I'll then typically shoot the whole night at 1/100th at say, f5.6 (w/flash it usually defaults to the 640ISO) - the camera automatically adjust the film speed to get a correct exposure. Pretty nifty.

[kamalakar]

The camera will pick the ISO needed given the aperture and shutter speed you have selected. Check your settings first. Set the default ISO to 200. Then set the max ISO and min shutter speed in the Auto ISO sensitivity settings. If you've done this and have a reasonably slow (as in as slow as you want it to ever go) shutter speed then it's likely that the camera has to go to ISO 1600 when you switch to A because the aperture you have selected is small enough that there isn't enough light to use ISOs lower than 1600.

________________________________________________

st lucia resorts
us post office passport application

[MikeHarris7]

well in my case I don't want to use anything lower than 640 ISO. Saves the batteries of my flash (crucial during a 6 hr wedding).

[DigitalScape]

Interesting option, Mike.  I'll have to see how the Canon handles this.

[motleypixel]

I'm thinking the same thing...my 5D2 better act this way   Thanks for sharing this insight.

[motleypixel]

Well, I don't think the 5D can do this.  In auto ISO it will auto adjust the ISO from ISO 100 to 3200 in P/TV/AV, but in M OR with flash attached it defaults to ISO 400...bummer!

[MikeHarris7]

That is a bummer. I've shot two weddings since I discovered this little trick, and it worked brilliantly. It's going to be a vital part of my arsenal going forward.

[motleypixel]

Yea I'm hoping I'm over-looking something.

[MikeHarris7]

here's an example of the technique in action. On a side note I don't know if this image would've been possible with any other camera than the D700. I need to go back and check but I think this is 3200 ISO folks...