rear sync flash
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A well illustrated link CT, but I'd really like to know why you say at the end:
"The moral is.. if it's moving and you're using flash then use second curtain synch regardless of the prevailing light."
If the subject is moving unpredictably, particularly like the guitarist in the pic quoted above, wouldn't you say that second curtain sync is not actually better, and indeed possibly adds even more unpredictability to the shot?
"The moral is.. if it's moving and you're using flash then use second curtain synch regardless of the prevailing light."
If the subject is moving unpredictably, particularly like the guitarist in the pic quoted above, wouldn't you say that second curtain sync is not actually better, and indeed possibly adds even more unpredictability to the shot?
I'm with CT on this one too. I use 2nd curtain sync for movement.
I think of it it terms of where in the image the movement is. With 1st curtain sync the movement can be all over the flash portion of the image, sometimes it seems to lie on top and can obscure portions of the flash exposure.
With 2nd curtain sync the movement is recorded behind the flash exposure leaving IMHO a much cleaner image but with the essence of the movement.
I think of it it terms of where in the image the movement is. With 1st curtain sync the movement can be all over the flash portion of the image, sometimes it seems to lie on top and can obscure portions of the flash exposure.
With 2nd curtain sync the movement is recorded behind the flash exposure leaving IMHO a much cleaner image but with the essence of the movement.
Ok - that explaines it better then. I would've posted the poctures but it was quite a long time ago and I now don't have them. Just remembered this as the occasion that prompted me to use rear-curtain sync.
I was referring to what Janice said and what you referring to - if the person closed eyes after the preflash with rear-curtain sync it will only matter when the whole exposure is short enough so the main flash will capture the closed eyes. If you have exposure that lasts a few seconds - this will be largely irrelevant since the the person blinking won't keep eyes closed all that time.
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Ali, I can only say what works for me, and I use slow-sync a lot for social events where a bit of movement coupled to some ambient light in the background is nice. Expressions and gestures are very quick, spontaneous and fleeting, and I find the best way to capture them is absolutely as soon as possible, ie first curtain sync. If any part of the ambient light image "seems to lie on top" of the flash exposure, the only way to reduce this is to use a shorter ambient exposure time, to darken the background; first or second curtain sync will not affect it.
Dalex, I understand what you're saying now, sorry, my mistake. Yes, if the exposure is long enough for the subject to have reopened their eyes after whatever made them blink in the first place, and then the flash fires completely unannounced, you've got 'em!
Dalex, I understand what you're saying now, sorry, my mistake. Yes, if the exposure is long enough for the subject to have reopened their eyes after whatever made them blink in the first place, and then the flash fires completely unannounced, you've got 'em!
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I've just been exploring the link posted by yoby earlier, Using Your Digital Camera. It's very good and has some clever animations. http://www.shortcourses.com/use/index.html
What we're discussing here is how the action of a focal plane shutter, as fitted to all D-SLRs, allows the flash to be fired either at the start of the exposure (first curtain sync) or at the end (second curtain sync).
This animation shows how the shutter works, moving from top to bottom of the image: http://www.photocourse.com/itext/flashsync/
There is a moment here when the whole of the sensor is uncovered, and this is when the flash is fired. (The duration of the flash is always very brief, even faster than the highest normal shutter speeds, so it will always absolutely freeze most things.) When the shutter duration is increased, say to 1/8sec or 1/4sec and longer times up to several seconds or even minutes, then obviously the subject can move quite a lot during this time, creating interesting effects with the ambient light. It's called slow sync flash, or dragging the shutter.
The question is what happens when a) you have a longer shutter speed, b) the subject is moving, and c) you have a choice to fire the flash at the beginning of the exposure (first curtain) or the end (second curtain). It makes a big difference, and if you know what's going on, you can control it for creative effect
What we're discussing here is how the action of a focal plane shutter, as fitted to all D-SLRs, allows the flash to be fired either at the start of the exposure (first curtain sync) or at the end (second curtain sync).
This animation shows how the shutter works, moving from top to bottom of the image: http://www.photocourse.com/itext/flashsync/
There is a moment here when the whole of the sensor is uncovered, and this is when the flash is fired. (The duration of the flash is always very brief, even faster than the highest normal shutter speeds, so it will always absolutely freeze most things.) When the shutter duration is increased, say to 1/8sec or 1/4sec and longer times up to several seconds or even minutes, then obviously the subject can move quite a lot during this time, creating interesting effects with the ambient light. It's called slow sync flash, or dragging the shutter.
The question is what happens when a) you have a longer shutter speed, b) the subject is moving, and c) you have a choice to fire the flash at the beginning of the exposure (first curtain) or the end (second curtain). It makes a big difference, and if you know what's going on, you can control it for creative effect