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<blockquote data-quote="'bini" data-source="post: 382986" data-attributes="member: 34724">I may be wrong here, but it seems you are confusing shutter speed with, I'll call it exposure duration...That 1/250th is your shutter duration, the time the shutter is open.&nbsp; Your camera won't properly synchronize with the flash at speeds above 1/250th.&nbsp; However, the exposure duration of the flash itself (the burst of light) will be much shorter, typically in the thousandths of a second.&nbsp; That burst of light must go off while both of your shutter curtains are open.&nbsp; On your camera, the rear curtain starts to follow the front curtain before the front curtain fully clears from in front of the sensor at speeds above 1/250th, so you only get a slit of exposure when the flash goes off.&nbsp; At 1/250th, both curtains are fully open when the flash goes off, giving that burst of light to the entire sensor. Now, if your ambient light isn't bright enough to cause exposure ghosting at 1/250th, your exposure will be just the duration of the flash itself, which will be fast enough to stop motion.&nbsp; If you get ghosting, move the flash closer to your subject, allowing smaller apertures.Hint:&nbsp; As you stop down the flash power from full to 1/2, to 1/4, etc., etc., the flash duration gets even shorter.Hope that helps.</blockquote>

[QUOTE="'bini, post: 382986, member: 34724"] I may be wrong here, but it seems you are confusing shutter speed with, I'll call it exposure duration... That 1/250th is your shutter duration, the time the shutter is open. Your camera won't properly synchronize with the flash at speeds above 1/250th. However, the exposure duration of the flash itself (the burst of light) will be much shorter, typically in the thousandths of a second. That burst of light must go off while both of your shutter curtains are open. On your camera, the rear curtain starts to follow the front curtain before the front curtain fully clears from in front of the sensor at speeds above 1/250th, so you only get a slit of exposure when the flash goes off. At 1/250th, both curtains are fully open when the flash goes off, giving that burst of light to the entire sensor. Now, if your ambient light isn't bright enough to cause exposure ghosting at 1/250th, your exposure will be just the duration of the flash itself, which will be fast enough to stop motion. If you get ghosting, move the flash closer to your subject, allowing smaller apertures. Hint: As you stop down the flash power from full to 1/2, to 1/4, etc., etc., the flash duration gets even shorter. Hope that helps. [/QUOTE]

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