In article <4gqlr7$5ke@newsbf02.news.aol.com>, tvulich@aol.com says...

>I'm wondering why it is that less expensive SLRs tend to have slower >flash sync speeds. For example the Canon EOS 1N syncs at 1/250, >whereas the Rebel syncs at only 1/90. Is this because the built in >flash units on cheaper cameras have less power, or is it something to >do with the electronic timing of the flash? I find this slow sync >speed a real problem when trying to use flash fill to eliminate
>shadows on a sunny day.

The synch. speed has nothing to do with the flash, and everything to
do with the shutter. It is necessary for the shutter to be fully open
at the time the flash is fired, or a partially closed shutter curtain
will leave its shadow on the film. At and below the synch. speed,
focal-plane shutters are fully open for the time of the exposure.
Above the synch. speed, a shutter slit (which is narrower for higher speeds) moves across the film for exposure . As a result, the shutter curtains must move faster (and, ah, more "expensively") to be fully
open at a higher shutter flash synch. speeds.
Hope This Helps