Rear Sync

Discussion in 'Lighting Equipment' started by thomson_chan, Sep 7, 2004.

  1. Dear all,

    I am new to my F80, and had never learn rear sync before.

    What does rear sync do?
    What is the difference with normal sync?
    What sort of situation would it be best used in?
    Could anyone tell me more details about this?

    Cheers,
    Thomson
     
  2. Rear sync describes the timing of the flash during the exposure. Say for example you're out at night taking a picture of a moving car, if you use the normal flash (assuming that the car is within flash range) the car will appear frozen, while the background will likely be black, or really dark. If you use the "slow sync" feature, the car will appear frozen, and the beginning of the exposure but the car lights will trail away from the car as they burn for the duration of the exposure. Also, the background will be more properly exposed. What is happening is that say your shutter time for the shot is two seconds, the flash is firing for probably about 1/60 of a second at the beginning of the exposure freezing the action, then the ambient light exposes the film for the remainder of the two seconds. To answer your question, we'll say that your shutter speed is again two seconds. Rear curtain flash will open the shutter for 1 second and 59/60ths just letting the ambient light expose the negative, and then for the last 1/60th of a second the flash will fire freezing the action at the end of the frame. To see an example of the cool effect you can get with rear sync flash check out this site http://www.toddpowell.com/frame2.htm and click on the middle picture of the right hand column (mountain biker at night). The best way to learn about the different flash setting is to just try them out, but write down what you do when you take the shot, that way you'll know what setting gave you the results you like. Hope that helps, enjoy!
     
  3. Traditionally the flash fires at the beginning of the exposure. Rear sync does pretty much the same as regular sync except the flash fires at the end of the exposure. You would use rear sync if you wished to create an illusion of movement. Here is an example, off the top of my head:

    Let's say you were photographing a timed exposure of a person on roller-skates as they skate by your camera from left-right, (1 second let's say). Using traditional sync the flash would fire at the beginning of the 1 second exposure freezing the motion on the left side of your frame and your subjects would continue to skate by through the 1 second exposure. Thus the subject would be ?froze? in place on the left side of the frame while there would be a streaked blur in front of the subject. This would seem confusing to the viewer because it would create a look as if they were skating backward.

    If you were to do the same shot but use rear sync the effect would be a blurred streak from the left with the subject being froze on the right. This would create a since of movement while still having a properly exposed, ?froze? subject on the right side of the frame. Boom! Instant implied movement.

    Hope this helps.
     
  4. in a dim setting Set your camera to manual mode, the flash sync to rear sync mode, and
    adjusting the shutterspeed from 1/60th of a second to 1 second and also adjusting the
    aperture to keep the exposure level constant accoding to your meter. then shoot some
    tests of someone walking around. That will teach you more about rear sync and the visual
    effects created than 10,000 words read here.
     
  5. Amen,Mr.Vener.There is entirely too much question asking,and not enough experimenting in today's world of amateur photography.
     
  6. Ditto. It costs little to try out various techniques. Experiment. Discover.

    For what it's worth, I think rear sync is overrated. It's trendy now because newer cameras offer the option. When I got a digicam that offered both sync types I tried hundreds, maybe thousands of shots both ways. Very rarely do I get a shot with the rear sync effect that appeals to me or gets the look I wanted. It's too difficult to anticipate when the flash will fire so timing the blend of motion blur and freezing action is non-intuitive.

    Normal sync with a slow shutter speed to capture a sense of motion from ambient light along with freezing the action from flash seems more intuitive and predictable. Just my opinion.
     

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