X-sync issue

[McMinnDSC]

The article on here was super helpful.

I was having trouble with low light flash situations with my Rebel XT while I was taking pictures of my son, who wont sit still. I had the aperture wide open to get the shallowest depth of field (on the tamron lens it only opens to f3.5), had the exposure set as low as possible (iso 100 on the rebel xt) and I was trying to shoot at shutter speeds above 1/250 (1/400-1/600 ideally) to avoid any blur, or trails, and I was not using a tripod (though I probably should have been)

...but I kept getting these black bars, little shadow of black covering the bottom quarter or so of the frame. I assumed it was the mirror getting in the way of the bright flash, or the shutter trying to close faster than the flash was filling. I thought that it may be a sync issue as I’m just using a cheap shoe flash...

So i tried lookign it up here and I believe the curtain sync and X-sync section explains what's going on here. And that there's really nothing that can be done about it.

So I don’t think there is, but I still just wanted to ask, if any of you have any suggestions or know of a way to get around this, while keeping the shallow depth of field, keeping a high enough shutter speed to avoid blur, etc.

accessories, firmware, anything.

though, getting my kid some Ritalin might help too...

there's just these specific shots i want to get, that are low light so i need the flash, i need the open apeture for shallow depth of feild, and the lowest iso is 100, but at shutter speeds below the 1/250 i get either the blur problem cause the subject is in motion, or the flash itself over exposes the pictures and i cant seem to dial down the flash enough to compensate, though that might be the best option. To somehow weaken the flash strength.

the cheap flash i have has the chart and like a simple switch for three settings, but is there somethign on-camera i'm overlooking?

[nkg]

The only way to use flash with a shutter speed that's higher than your camera's X-sync is to use FP mode flash. This mode, also known as high speed sync, is available with Canon Speedlite and compatible units, but not with simple manual flash units. Or you can up the ISO, or buy a lens that lets in more light. Or wait until the kid has a nap!

[Tiberius]

Another alternative is to use a constant light source. There are quite a few desk lamps you can pick up from a homeware store that will do the job.

If you must use the flash, you'll need to get your shutter speed under the flash sync, as NKG mentioned. Bumping the ISO up to 400 or so may let you do that.