Can someone explain 'flash sync speed'

[dinanm3atl]

I am reading it in another thread and cannot understand 100%.

I shoot a Canon 40D so what is my max and what does it mean and how does it affect me?

For flash use I really just use my 430ex on camera with a diffuser :)

[OneStrobe]

Iono how to explain it, but here's a good way to find out why you shouldn't go above you flash sync speed.

Shoot at 1/250 F5.6 with an external flash triggered with radio triggers - Everything is all good and dandy

Shoot at 1/500 F5.6 with the same set up - Wonder where half of your picture went?

The normal top sync speed for cameras is 1/250 - 1/200 shutter speed. Anything above that is most likely TTL or some high speed hack.

[mpoole]

The shutter is only open across the entire sensor up to your max sync speed. At speeds above that, an opening in the shutter travels across the sensor. The flash itself may last only 1/1000 of a second, so only a part of your sensor sees the light

[bobbyz]

Click on this link:

http://www.pocketwizard.com/inspirations/tutorials/pocketwizard_controltl_optimiz/

[gonzogolf]

Just in case neither of those made it clear I'll take a stab. Your flash fires a very short blast of light, as fast as 1/1500 of a second or faster depending on the flash and amount of power needed. Your shutter is composed of two curtains with a space between them. up to 1/250 of a second it works like this. You push the button, the first curtain opens, he sensor is exposed and then the second curtain closes, thats your shutter speed. Faster than 1/250 on your camera the second curtain starts to close before the second curtain has completely opened leaving only a portion of the sensor exposed. If your flash were to fire above that speed you end up with only a portion of the sensor exposed and a black shadowy band on the part of the image not exposed by the flash. Canon speedlights have High Speed Sync mode that gets around this to a degree. They fire multiple pulses of light for the duration the shutter is open, but they cannot fire full power in this mode so you get a reduced flash range. The max sync speed is a function of the camera, not the flash.

[StanNJ1]

I made a video tutorial that covers this which you might find helpful
http://photography-on-the.net/forum/showthread.php?t=684587

[mufutau55]

Heh! Howdy Stan. You disappeared for a while after you made that video.. That was a very good informative video. As said before, Thank you again.

Mufutau

I made a video tutorial that covers this which you might find helpful
http://photography-on-the.net/forum/showthread.php?t=684587

[FlashZebra]

To understand you X-sync speed imitation, you must understand the mechanics of the focal plane shutter in your camera.

See:

http://en.wikipedia.org/wiki/Focal-plane_shutter

Enjoy! Lon

[dinanm3atl]

Thanks guys!

[AxxisPhoto]

The maximum flash sync speed is the fastest shutter speed at which the entire image sensor can be illuminated by flash pulse.

[Curtis N]

Slow-motion videos showing various focal plane shutters in action, both above and below X-sync speed. They illustrate the concept pretty well.
http://www.smugmug.com/gallery/8945351_aVDzo#594124511_2CUHh

[runninmann]

Slow-motion videos showing various focal plane shutters in action, both above and below X-sync speed. They illustrate the concept pretty well.
http://www.smugmug.com/gallery/8945351_aVDzo#594124511_2CUHhIt was interesting to compare the amount of mirror bounce among the 5D, 20D and 50D. I suppose one would expect the 5D to exhibit more due to its greater mass. It looks like the 50D dampening is much better than the 20D. Of course, I don't know how age/use/wear would affect it.