40D: Av Mode and Flash?!

[edryn80]

Playing with my new (to me) 40D last night.

When in Av mode, I put the flash up manually but it did not adjust the shutter speed to tie in with the flash so it was exposing for no flash then the flash was nuking everything. I'm sure my old 350D adjusted the shutter accordingly, should the 40D not do the same? :shrug:

The only way of getting the camera to expose correctly with the flash was in P or Auto. Or in full manual of course.

Ta

 

[Orange Peel]

In Av you can change the flash exposure compensation by using the big dial on the back. On the top of the camera near the display look for the iso/flash comp button. Press it once then use the dial to +/- the flash.

 

[POAH]

in AV mode the camera only uses flash as fill so the exposure is generally not adjusted. if the flash is overexposing check your FEC is not sitting at +2. putting the camera in P or auto means the flash will try to illuminate the subject rather than just fill. It tells you this in the manual which I suggest you read for more info

 

[GTB79]

The 40d has a custom function that changes the shutter speed to a fixed 250 in av mode when using flash.

If you go through the custom function menus you should find it.

 

[HoppyUK]

The 40d has a custom function that changes the shutter speed to a fixed 250 in av mode when using flash.

If you go through the custom function menus you should find it.

I think this is the OP's problem. Previous owner has changed the custom function setting.

There's another handy flash option on the 40D, in P mode. It will allow the shutter speed to track the ambient but only down to 1/60sec, to avoid too much ambient blur. After that, it just lets the background get progressively darker. Might be a useful compromise setting?

 

[stevedunster]

I think this is the OP's problem. Previous owner has changed the custom function setting.

There's another handy flash option on the 40D, in P mode. It will allow the shutter speed to track the ambient but only down to 1/60sec, to avoid too much ambient blur. After that, it just lets the background get progressively darker. Might be a useful compromise setting?

The 5D2 has a custom function to get Av to do this too, might be worth looking to see if the 40D can too.

When you're in P mode, it will also handle closing the aperture down when the sun gets too bright if you've not selected high sync speed. In Av, you've got to handle this yourself.