RobertV — I too like a good debate so no worries at all.

The LESS delay (for mission critical timing) I was talking about refers to the delay related to the flash firing toward the end of the exposure which of course does not affect overall exposure, or flash duration. I’d have to set up a test to prove this for fast shutter speeds and the effect might not be easily noticeable but imo, you’ll MISS more shots with rear sync than with front sync for your average shot where the subject is moving in a linear fashion. Why? Simply because most of us are not used to capturing images in this way. Perhaps you may be, but I dare say most people are not. When the exposure is one second, we naturally expect to see the flash burst at the beginning of the exposure (closer to the moment we click the shutter). The delay throws people off to a degree, the longer the delay, the more the degree.

So, if you buy that, given that it’s harder for most people to precisely freeze a moment with flash with a slow shutter speed on rear curtain sync (even on my own experiment when I ran my hand though the frame, it was harder to freeze the shot without missing it on rear curtain sync), to my mind it only stands to reason that the same effect will happen with a faster shutterspeed though it may be less noticeable. Please note we are only talking about moving subjects here.

Do you feel this logic holds?

In terms of manual versus TTL, for outdoor shooting, there too we differ. I almost never shoot manual (I shoot mostly portraits) outdoors because I don’t want to have to think about the ambient light changing slightly and my not noticing it. Also rarely is my flash the main light, it’s usually fill.

I normally only use manual when I am in full control of the lighting as in a studio, or my on camera flash is the primary light source. But everyone shoots differently and it also depends the subject matter you shoot, flowers are always more forgiving of an improperly exposed photo than a bride and groom for example.…but now I digress.

Thx again for the food for thought! Marko

I’ve shot quite a bit of studio/model work over time and always manual flash control from the 580ex2’s or the studio lights. Even when outdoor light balancing I always use manual flash. I guess this is the reason I’ve not had a problem with blinkers(from the pre-flash.)

I don’t really agree with the “Front curtain sync lets you freeze the action as it happens with LESS delay.…” part though. The flash durations and the camera exposure time will remain the same regardless or FC or RC sync.The camera still has to sense the pre-flash and the flash, regardless of the timing. If things are moving and timing is critical then the shutter time becomes the critical element. Also, I’d feel this is exactly the instance where you do want SC Sync. “Mission critical” timing issues really need manual flash anyway, as the pre-flash systems all introduce delays.

Hopefully this doesn’t sound like I’m arguing. I love a good debate on technical matters as my daily job depends on this. They don’t call me “Dr No” for nothing! Closely analysing things many people only give a cursory view is my job, as is saying “No, I don’t agree, because …”

Also when shooting people in TTL mode, Rear sync introduces a PRE FLASH that you never see (it’s there but you don’t see it because it happens too close to the actual flash burst) in front sync flash. This preflash can be damn annoying to your subject and cause your subject to instinctively blink between the exposures. You will clearly notice this preflash as your exposure gets longer. This preflash will NOT happen if the flash is in manual mode, just as an FYI.

Yisehaq — You are correct, for stationary objects, no difference imo.

I cannot think of any reason for it to be the other way. With that in mind, I always set Second Curtain on my cameras and flashes.

As for the wedding flowers, It really wants a 1/4 or 1/2 CTO to match better. Nice shot all the same.