In Live View and AV mode on 5DMKII the ISO auto changes to 6400 for no reason, any solutiions?

[jtkaminsky]

In Live View and AV mode on 5DMKII the ISO auto changes to 6400 for no reason, any solutiions?

[Mykolas]

Hi jtkaminsky!

Thanks for posting.

Just like shooting through the viewfinder, in AV mode, you select the aperture you want to shoot at while the camera selects the appropriate shutter speed and ISO speed (if you have ISO set to Auto).  What is likely happening is the camera is metering the exposure and determining that the exposure is too low, so it chooses a higher ISO speed to compensate.  This is normal.

[jtkaminsky]

Camera is in AV mode and ISO is set to a specific number i.e. 100 or 200.  In Live View the ISO is cahnge to 6400 without my changing ISO to auto. and it takes the picture at 6400 regardless of the set ISO.

[TCampbell]

If ISO is set to 'auto' then the camera can change it.

If ISO is set to a specific value then the camera will leave it alone (even if it means not being able to get a correct exposure for the shot.)

On the 5D II, the top ISO button is the button nearest to the main selection wheel.  Is it possible you are bumping that button and changing the ISO without intending to?  (e.g. would the ISO change even if the camera were on a tripod and you weren't touching it?)

[amfoto1]

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jtkaminsky wrote:

Camera is in AV mode and ISO is set to a specific number i.e. 100 or 200.  In Live View the ISO is cahnge to 6400 without my changing ISO to auto. and it takes the picture at 6400 regardless of the set ISO.

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In other words, you don't have Auto ISO enabled... right?

On many Canon there is a Safety Shift feature that will override your settings if the camera thinks your settings are inadequate for the purpose... I'm not sure if this would change the ISO or the aperture or the shutter... but it will change something in order to "correct" the exposure.

EDIT: I just looked at my 5DII... ït's Custom Function I: Exposure, 6 "Safety Shift". Check to see if that's enabled.

I never use it and in the manual it indicates it will only work in Av/Tv mode, but it doesn't say what settings will be changed. I imagine if it's more than can be adjusted overriding shutter or aperture, the camera might then change the ISO too.

***********

Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories
FLICKR & EXPOSUREMANAGER