Hi, The EOS 5 has second curtain sync as a custom function. I understand what this is for but I'm not sure why you would ever want first curtain sync. Could someone post a situation where first curtain sync would be preferable? - Thanks.

-- Paul Cummings (planb@qsilver.net), November 18, 2000

Answers

"Could someone post a situation where first curtain sync would be preferable?"

- Nope. Unless you want "leading" light trails. I leave mine on all the time.

-- Jim Strutz (jimstrutz@juno.com), November 18, 2000.

I just thought of a reason to use first curtain sync. If you were using the built in flash (or a hotshoe mounted Speedlite) to optically trigger other slave lights, especially studio strobes. The short delay of the slave trigger or the long flash duration of the studio strobes could put some of the flash into the shutter blades as they started to come down.

Anybody else have reasons for first curtain sync?

-- Jim Strutz (jimstrutz@juno.com), November 18, 2000.

In principle, I can't think of any reason to use first curtain sync. In practice, a BIG BIG reason why second curtain sync. is pointless is that the evaluative pre-flash still fires before the shutter opens, causing your subject to think the photo is done and begin to move away. Of course, this only matters for shutter speeds of more than a quarter a second or so. Anyone have any thoughts on this?

-- Warren (warrexa@yahoo.com), December 04, 2000.