Front curtain vs Rear curtain?

[Firebot]

I've been reading a lot about lighting recently especially since getting my new flash, and got to the subject about front curtain versus rear curtain. By default, flashes are set up as front curtain where the flash shoots at the start of exposure, but rear curtain takes the shot at the end of the exposure. This not only allows you to shoot in Av mode at slower shutter speeds then 1/60, but keeps the subject sharp while causing potential movement blur in the background when using slow shutter speed. Am I right in understanding this?

Knowing this, shouldn't I always be selecting rear curtain as my flash setting? In what situations would front curtain be preferable?

[chrominance]

Let's say you're taking a picture of a car driving past you at night, and you want to see the light streaks left by the headlights but you also want the car itself to be properly exposed. If you leave the flash set to front curtain, the flash will fire first, and the streaks will appear in FRONT of the car, instead of behind as you might expect. If you set it to rear curtain instead, the car will be exposed last and the streaks will appear to be coming from behind the car.

It's easier to explain all this with an illustration but I couldn't find one quickly on Google. Hopefully the above description makes sense.

[chrominance]

Oh, I think I may have misread the question a bit. The main compelling reason I've seen to use front curtain flash is if you want the flash to fire when you hit the shutter, i.e. when you're trying to time a shot perfectly.

[gotak]

It's been said that for long exposure with human subjects when using ETTL 2nd curtain can cause people to think the photo's been taking, due to the metering preflash being so far from the actual 2nd curtain flash.

Not sure if this is really valid cause you can just tell people to stay still till you tell them they can move.

[Lulz]

cool. will subscribe to this thread

so rear-curtain is only needed when you're shooting moving cars at night, lol?

[kay188]

so rear-curtain is only needed when you're shooting moving cars at night, lol?

Unless you can think of a better reason for rear curtain. =P

[Dr_luv]

Here is a picture I found on flickr of a similar application of rear curtain sync. (http://www.flickr.com/photos/silverback40/4041069132/)

Very nice example of rear sync... (http://www.flickr.com/photos/enigma1977/2643178196/) Original strobist discussion here. (http://www.flickr.com/groups/strobist/discuss/72157606600597469/)

Here is one of front curtain sync (http://www.flickr.com/photos/andrewnemo/2993415545/)

[Firebot]

Here is a picture I found on flickr of a similar application of rear curtain sync. (http://www.flickr.com/photos/silverback40/4041069132/)

Very nice example of rear sync... (http://www.flickr.com/photos/enigma1977/2643178196/) Original strobist discussion here. (http://www.flickr.com/groups/strobist/discuss/72157606600597469/)

Here is one of front curtain sync (http://www.flickr.com/photos/andrewnemo/2993415545/)

Very good info there thanks will read the discussion there.