waterrockets wrote in post #14763365
I hear you there. Short story: you cannot get faster than 1/200 shutter speed with pop-up flash on the T2i.
To address your problem, can you tell us what mode you are shooting?
I would recommend M at f/1.8. Set your ISO and FEC such that the flashed subject looks correct, then work with your shutter speed to get the background off the left side of the histogram a bit.
With the un-modified pop-up flash, your shots will pretty much always look like they came off of a point and shoot camera because of the flat lighting. You can make some simple bounce devices with scrap paper products from your kitchen that will bounce up to the ceiling, and the shots will improve DRAMATICALLY.
Lastly, don't think you have to spend $570 to get external flash. Yongnuo has ETTL flash for $70 that will bounce just fine. Throw it on AV with the flash pointed at the ceiling, and indoor shooting will get a lot simpler in a hurry.
Sorry, again I should've said that I almost always use Av mode.
Didn't even cross my mind that changing to M would solve the problem. D'oh! 
I think $70 is about £40-50 so that's pretty reasonable actually.
Thanks for your help.
Monkey Mash Button wrote in post #14763418
Somewhere in the menus (custom functions maybe), you can set what Av mode will pick for a shutter speed when using flash: something like 1)Auto, 2)1/60-1/200, or 3)1/200. I throw the camera in manual, expose for the background (or under-expose by a stop or so), and let the ETTL flash do its thing. I pretty much start with ISO 100 and 1/200 shutter and then dial aperture to taste. I've also set Tv mode to 1/200 for run-and-gun outdoor fill flash. The pop-up flash doesn't have much range, 10-15 feet or so.
I've never tried taking the ISO over 400 with flash so didn't know that was a limitation.
and +1 to what waterrockets wrote. Bounce that flash indoors! The pop-up flash will diffuse and/or bounce indoors with a little cleverness.
I'll have a look in the menu settings, thanks.
By the way, one of the situations I was talking about was with this shot taken in a hotel on holiday.
This is the exif info:
1/60 second
ISO 6400
f1.8
Focal length 50mm (nifty fifty)
Mode: Tv
Flash: off
IMAGE LINK: http://www.flickr.com …/56558970@N07/7639347148/
IMG_1923_6392
by
inchpractice
, on Flickr
Luckily I managed to get rid of most of the noise in PP but the image is still very underexposed.
I suppose ideally what I wanted was a manageable ISO, a shutter speed of at least 1/80 of a second and the flash to fire.