Rear sync

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wookie6262

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I've been hired to shoot an Athletics meeting tomorrow and the brief has just said be as creative as you like. I'll shoot all the standard shots but thought I would try some pans and drag the shutter. I had a practice tonight and got a couple I liked through trial and error. Has anyone got any tips for set up. I shot the images tonight with a AD300 off camera but that limits the area I can take the shot to in front of the flash. Perhaps a speedlight may be a better option and up the iso a wee bit. I'm looking to show a decent amount of blur so wanting something around 1/10th or a 1/20th shutter speed. All the races are 1500m minimum so the runner will be at a moderate pace.

Ideally what I would like is the chance to shoot two or three shots as the runners go by with runners frozen and background blurred through the pan. If the runners were a stop or so brighter than the background I think I would like that look too. So would the best bet be to get a shutter speed sorted first. Then a largish aperture like F4 and then get iso to the level needed to expose correctly. It is an evening meeting so shouldn't need ND filters. Next do I use TTL or manual flash. I guess I can shoot manual if panning side on as the distance won't change dramatically. If I am panning from around 45 degrees the distance will change so I dare say TTl will be needed.

Has anyone tried this before at Athletics or other outdoor sports. It could all be academic of course as I haven't had the use of flash approved yet
 
I find panning athletics very tricky as there is a lot of up and down motion as well as along. maybe some of the disciplines would work, e.g. long jump? for running, maybe try rotations, that might work better?
 
I gave the rear sync a go at the Athletic. Mixed results and a broken hot shoe for my troubles. I need to practice flash in general and even more so when combined with moving subjects. A good experience though and only did a couple of races as the results weren't as repeatable as I would have liked. I think that was due to me firing too early and the range of the flash being exceeded. Next time I am going to try a much longer shutter speed and get the ambient exposure closer to the runner.
 

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The only time I've used rear curtain synch specifically was to freeze a bike at the front end of a light trail.
 
wookie6262 said:
I gave the rear sync a go at the Athletic. Mixed results and a broken hot shoe for my troubles. I need to practice flash in general and even more so when combined with moving subjects. A good experience though and only did a couple of races as the results weren't as repeatable as I would have liked. I think that was due to me firing too early and the range of the flash being exceeded. Next time I am going to try a much longer shutter speed and get the ambient exposure closer to the runner.
Click to expand...

Be aware that rear-curtain sync is not actually enabled until the shutter speed drops below 1/30sec (see handbook) even when it is switched on. Even then, it is more like 'middle-curtain' sync and not really effective until shutter speeds get a couple of stops longer than that - the longer the better really.

Some flash systems allow you fine tune the exact firing moment to tailor it exactly to your particular camera's shutter characteristics and reduce the 'middle-curtain' effect somewhat, but the real key is longer shutter speeds.
 
HoppyUK said:
Be aware that rear-curtain sync is not actually enabled until the shutter speed drops below 1/30sec (see handbook) even when it is switched on. Even then, it is more like 'middle-curtain' sync and not really effective until shutter speeds get a couple of stops longer than that - the longer the better really.

Some flash systems allow you fine tune the exact firing moment to tailor it exactly to your particular camera's shutter characteristics and reduce the 'middle-curtain' effect somewhat, but the real key is longer shutter speeds.
Click to expand...
That now explains why I got different style trails dependent on my shutter speeds. I can't see any details of what you are saying in the manual for the A1
 
wookie6262 said:
I can't see any details of what you are saying in the manual for the A1
Click to expand...
I think it depends on the make/model... Many (most/all?) Canon's trigger rear curtain at 1/30; on Nikons I believe it starts at 1/125 (no idea about Sony/others).

Either way, the flash timing must be made so that the flash contribution completes before the rear curtain starts to move (probably timed for a slower OEM speedlight at full power). And that tends to leave a gap between the flash exposure and the rear curtain ending the exposure... the faster the SS the smaller the front gap becomes and the more the rear gap matches the front gap, which moves the flash exposure more towards the middle.
 
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sk66 said:
I think it depends on the make/model... Many (most/all?) Canon's trigger rear curtain at 1/30; on Nikons I believe it starts at 1/125 (no idea about Sony/others).

Either way, the flash timing must be made so that the flash contribution completes before the rear curtain starts to move (probably timed for a slower OEM speedlight at full power). And that tends to leave a gap between the flash exposure and the rear curtain ending the exposure... the faster the SS the more the rear gap matches the front gap, which moves the flash exposure more towards the middle.
Click to expand...
Cheers, Hoping to use it a bit more and will definitely experiment with slower speeds.
 
The particular shutter speed when rear-curtain sync is enabled is kind of irrelevant anyway. Canon certainly states 1/30sec and I thought Nikon too, but either way what makes this technique effective is a long enough exposure to create some significant ambient blur before the flash fires, and in practise that's 1/15-1/8sec or longer, even with fairly fast moving subjects.

Try some experiments, and also remember that when you're panning at the same time, the subject is effectively stationary in the frame and not creating movement blur. It's suck it and see and while rear-curtain can work very well in some situations, it's widely misunderstood and often over-rated, producing results that actually don't differ in any useful way from normal sync. There are downsides too, again depending on the subject (social events, night clubs etc).
 
HoppyUK said:
The particular shutter speed when rear-curtain sync is enabled is kind of irrelevant anyway. Canon certainly states 1/30sec and I thought Nikon too, but either way what makes this technique effective is a long enough exposure to create some significant ambient blur before the flash fires, and in practise that's 1/15-1/8sec or longer, even with fairly fast moving subjects.

Try some experiments, and also remember that when you're panning at the same time, the subject is effectively stationary in the frame and not creating movement blur. It's suck it and see and while rear-curtain can work very well in some situations, it's widely misunderstood and often over-rated, producing results that actually don't differ in any useful way from normal sync. There are downsides too, again depending on the subject (social events, night clubs etc).
Click to expand...
I should have practiced more as I played it too safe with the shutter speeds. Might give it a go again soon
 
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