My current love, as you all know, is the 85mm lens. The Canon 85mm f/1.2L lens, to be precise, on my full-frame Canon 1Dx camera.
I love this lens for many reasons. One is that f/1.2 is great when I want to shoot in a classroom without using a flash or going to very high ISO values. As a bonus, I get great separation between foreground and background.
As in these three very recent shots of students:
This lens is the perfect length for half body shots like this; and it is long enough to get blurry backgrounds even at f/5.6. Witness this, at Yonge-Dundas Square in Toronto (see here for the whole story):
If I move farther back, it is usable for full body shots too, of course:
Because it is a prime, it gives me the consistency I love: f/6.3 is f/6.3, and 1/100th sec is 1/100th sec. (With a zoom, on the other hand, you have to get used to motion blur effect and blurred background effect being different at every zoom setting.)
With this lens, I need to remember to move back and forth, and to leave enough space. But the point is that you can do that easily enough.
If you use a crop camera, a 50m lens would give you a comparable effect.
OK, and as a final shot, a screen shot from Sun News TV that aired two days ago, with the two Topfree Rights women and me taking photos of them: