...so in the mean time have a 50mm f/1.8 prime lens (cheap and cheerful 'plastic fantastic'). The camera is a canon 550D (so enthusiast end of entry level).
If you still want a 50mm prime, just a better one, the f1.4 is one of the best lenses Canon make and they're not too pricey, especially second hand. We have a lot of Canon lenses at work for shooting reference photos on set and I did an exhaustive test of all the lenses we have to work out which was the sharpest with least distortion and, unsurprisingly, the fancy telephoto came out best but the 50mm f1.8 was a very close second.
The lens I'd avoid is the 28mm F1.8 which I bought for the only Canon I've ever personally owned. It's a rotten piece of glass and is so soft wide open that it's pretty much unusable in low light (which was precisely the reason I bought the damn thing in the first place).
If you're getting the 15-85 zoom, a low light prime lens might be handy to have as the zoom only goes to f3.5 at its shortest focal length which gets tricky in dimmer lighting conditions.
Hope you get to love photography as much as
Telecasters drop-tuned machines of war.
