I Need Some Advice Please

[Kirislin]

I was taking pics on the weekend with my 7D. I had it on high speed continuous TV priority. I noticed it often would change the aperture in a succession of shots when the conditions were the same. I realise if I'd had it all set on manual this wouldn't happen but I'm not so experienced I can judge the right settings. I was hoping the camera would get it right.

Not sure if I am explaining this properly. Here's an example

TV1600

AV 4.0

and a split second after

TV1600

AV 2.8

I dont know it I am doing something wrong or there's a problem with the camera.

[ruthless]

Why not do one test burst on TV and then check the LCD screen to see which exposure you like and then set it to M?

[Kirislin]

Why not do one test burst on TV and then check the LCD screen to see which exposure you like and then set it to M?

Because that makes too much sense.

[Guest Tess32]

It only takes a slight movement depending on what metering mode you're using, for the exposure to change.

[rubiton]

As Tess has said - it could be exposing for the whiteish dog then exposing for the green grass. Use the light meter and set on M and it should hold the settings (though some of the later ones do change aperture etc slightly if the image will be under exposed according to what I read on a forum or manual somewhere and its something you can leave or switch off in the custom menus).

I sometimes get that anyway with the 40D even on Manual but not often and one or two in a burst of 30 images is not a problem and doesn't happen all that often (didnt notice it in the 10,000 odd photos taken so far in Sep).

To use the light meter in that situation point it at the grass to set the settings too and then take a test picture of the grass etc and compare (if you screen is set correctly it should look the same as the real thing)