IF you're in the market for a Canon EOS SLR, you might be tempted to do what I did and get this lens instead of the 'kit' zoom lens.
I'm not saying you shouldn't, but there are some points to consider.
On a camera like the EOS 400D, this lens effectively becomes an 80mm lens. So without a tripod, you really need shutter speeds upwards of 1/100 to avoid camera shake.
Well that's fine, you think, because at f1.8 you can surely get the shutter speed up. Indeed you can, but the depth of field becomes razor thin. Not only that, but focus becomes very important. Slightly out and you've lost it, so you really can't afford to focus-lock and recompose at f1.8.
And... at f1.8, sharpness is only so so.
Still, this is a very cheap lens. And in the right conditions, it gives great results. It's very sharp indeed if you stop down even to f2.8 and seems to me to remain so through to f11 at least.
You might want to get this lens for great blurred backgrounds, and it does pretty well with this, for sure. The only snag is that any highlights (discs of coloured out of focus light, are a funny shape because of the diaphragm. At least they're smooth and flat.
The lens focuses as close as 45cm so photos of flowers are a posibility.
One thing I don't like is the MF/AF switch on the lens, which is too stiff. And the tiny focus ring right at the front of the lens is a bit hard to find and use.
But the lens is small, very light, very cheap, great for portraits and (like any lens) capable of very sharp results - in the right conditions.