Originally Posted by jmacavali
I also have a T2i and it won't do 1/800 of a second for shutter speed - at least that I'm aware of.
It should be able to operate at 1/4000 of a second, when not using the flash. Check the specs
Notice "Flash X-Sync: 1/200 sec"
By leaving the shutter open longer when taking flash photos the background, which will usually be underexposed, will show up a little more in low light. The subject, or whatever is close enough for the flash to light up well, has the flash to control it's exposure.
Some cameras have rear curtain slow sync flash mode. If you took a photo of a moving car at night using rear curtain slow sync flash the shutter opens, the lights of the car will make lines on the exposure, then just before the shutter closes the flash goes off exposing the car and leaving lines trailing behind the lights of the cars so it really looks like it is moving.
Have lots of fun playing with your camera, but be sure to get around to reading the manual. I know I took tons of photos before checking the manual out, but I did eventually read it cover to cover and I'm glad that I did. You know what they say about computer manuals! RT*M