It depends on what format you're using.
On a full format dslr the 85mm is 85mm just like on film, but a smaller sensor like the Nikon DX would make that a 127.5mm and it would turn a great portrait lens into a small telephoto.
I have a 85mm 1.8 and it's just amazing to use. Having such a fast lens really makes a
HUGE difference at dusk and other low light situations where on a slow lens I'd need to up my ISO.
I just recently posted this one, but it was taken with the 85mm, so here it is again.
1/40, f3.2 @ ISO 2000.
Sure I could have dropped the ISO a lot and just used 1.8 but it's almost impossible for me to get a hand held shot at 1.8 and get it in perfect focus.
1/320, f8 @ ISO 200.
Alright, I uploaded this pic straight from a nef raw file conversion so it's completely untouched and the file size is like, 7mb. Prime lenses are sharp, super sharp, look at the detail in her hair and this was with my shaky hands and no other support. And I wasn't even that close, hence why people love 85mm as portrait lenses. The only problem is that skin imperfections really start to show up, so just be careful if you're shooting portrait.
*Edit You have to save the penguin picture to your hard drive, imageshack resizes it for some reason and I couldn't find a way to get the image back to 2848x4288 and you lose a bit of the sharpness/quality with the resize.
