Setup: EOS 3 on tripod in Av mode, eval metering with EF20mm lens. 540EZ on the hot-shoe, but switched off. Camera already switched on and suggested shutter speed known to be 1 sec.

If I switch on the flash, the ambient meter changes to suggest 2 sec. If I switch off the flash it returns to 1 sec. If I change to Manual mode on the camera and set the suggested 1 sec shutter speed I can see the ambient meter reading drop 1 stop when I switch on the flash. (I tried both ceiling-bounce then direct orientation of the flash head).

I also discovered that while second curtain synch set on the flash works fine, second curtain synch set on the camera via custom func #15 = 1 does not work.

While I did not have time to play further at the time, I will investigate further with new batteries, clearing custom settings, cleaning contacts etc etc.

Please could anyone with this combo of camera and flash tell me if these oddities are normal or not?

-- Paul McSweeney (paulmcs@clear.net.nz), January 04, 2001

Answers

The camera might be using a different metering pattern for ambient light while the flash is on.... try the same experiment with the camera pointed toward a uniformly illuminated wall.

-- Dave Herzstein (dherzstein@juno.com), January 05, 2001.