How important is flash sync speed?

[Ouvinen]

1/200s is a pretty fast sync speed, only the pro slrs sync to 1/250, most amateur cameras sync to something like 1/125 or something. The thing is, that you sometimes want to use just a little fill and freeze the action with a fast shutter speed. The fast sync speed helps here. Although I think 1/200 or even 1/250 ain't fast enough to that. With an EX series speedlite (or a Sigma EF500 DG Super at half the price of a 550EX...) you'll get FP flash, (focal plane / fast pulse) that you can use with shutter speeds up to 1/4000 or somerthing. That isn't of course as powerful, as it shoots a very fast strobe of light to cover all of the frame in while the shutter opens. That is however very usable as a fill light when you want to use a fast shutter speed and / or blur the background out with a large aperture...

[ThoughtfulPirate]

But why can my point and shoot use flash at all shutter speeds?

[another view]

If you're posting that question here, then I'd say it's pretty important! Check out the Nikon D70, it's got an unusually high sync speed of 1/500. Most pro SLR's (digital or 35mm) top out at 1/250, and my Fuji S2 has a painfully slow 1/125. This is a time where you can't get too much of a good thing, the faster the better although 1/250 usually gets the job done.

Fast sync speed not only keeps a moving subject sharp (no blurring around the edges) but it also lets you use a wider aperture to blur the background since it's more out of focus. The really fast sync speeds (like the 1/4000 that was mentioned) work differently than usual; you'll need to use some manual settings to do it. Check out how it works before you get too serious about a camera if you intend to use it.

I guess I can't answer why your p&s does it though...

[ThoughtfulPirate]

Yeah, I guess I should look at the D70, its too bad since I have canon lenses.

[Sean Dempsey]

might the PnS camera have a greater shutter lag than a SLR? I Was under the impression that after like 1/250, the shutter would fire before the flash had a chance to even fire, with the tiny delay it took to get the message, ala the strobe flashing..

maybe the PnS has a shutter lag that allows the signam to be similtaneously slowly sent to the shutter and flash, whereas SLR cameras are more concerned with an accurate and short shutter lag.

[ThoughtfulPirate]

Could be, but I have shot with shutter speeds over 1/1000 with my flash, and it still lit up the scene quite well.

[Ouvinen]

Whereas SLRs have a mechanical (although electronically controlled) shutter, most digital compacts don't. Their 'shutter' action is just made by activating the ccd for the chosen 'shutter speed'. The ccd is operational all the time, that's why you've got ccd viewfinders on them, but not on DSLRs. Syncing a mechanical shutter and a flash to fast shutter speeds is physically harder, thus the usual sync speeds are what they are... That's how I figure it...