i'm not really sure why people say that 70-200mm is good for
portraits yet i see other post that ask 'is a 50mm 1.4 any good for
portaits' and is usually followed by a torrent of people saying
that 50mm on a 1.6 is too long!
i understand that portatits from a distance would be best taken
with a longer lens but...you see what i mean?
Wow, that's crazy. I believe a good photographer can make a good
portrait with just about any lens, but typical portrait lenses are
in the range 80 - 150. Read about people using 645 medium format
and you'll see very similar focal lengths (110 being a bit too wide
= 66mm equiv, 250mm being a long portrait lens = 150mm equiv,
typical = 150-200 = 90-120mm equiv).
A 50mm lens on a full frame camera is generally considered too wide
for head and shoulders portrait work. But on a 1.6x camera it's
more-or-less an 80mm lens, which is a short portrait lens, and
seems like a good focal length to use (meaning you tend to take
photos at a distance which is close to the minimum for a flattering
look -- not too 3D, not too 2D).
I see some people using and recommending the 24-70 on a 1.6x camera
for portrait work. It's way too short on a full-frame, but goes to
112mm equiv on the APS-C cameras so would seem to be useful. The
annoyance is that these two pro Canon zooms (24-70, 70-200) split
the portrait range. You'd like something like a 40/50 - 100.
Maybe Canon will have something like that in an EF-S mount sometime
(like the Olympus 35-100 f/2 lens for the 4/3 system).
Anyway, for a 1.6x camera I think the 50/1.4 would be a good choice
as well as the 85/1.8 (or 85/1.2). Maybe a 100 for long work, and
the 135/2 is unfortunately long for portrait work without a lot of
room (since it'd be over 200mm equivalent). If you like everything
in focus, then the 50/1.8 will work quite well, but as soon as you
get blurred highlights the 5-blade diaphram doesn't look so good.
As usual, my opinions only, and I'm no Monte Zucker (who uses a
Canon 70-200 f/2.8 IS, by the way) or even close. One more
reminder that with some creativity and work you can make a great
portrait with a 20mm lens or a 500mm lens, but I was thinking of
traditional portrait lens lengths.