.
People often put these two lenses up as an 'either-or', in fact I did that myself
last year with the same type of thread. Then I ended up with both, and they really
do compliment each other - in fact, when I don't mind carrying the weight and
I don't really know what I'll be shooting that day, I sometimes bring them both as a kit.
I've often said that if you wanted to save your money for only three good lenses
for Pentax, they should be the 12-24, 50-135 and 77ltd. (or sometimes I think
77ltd <---> 43ltd)
Here's some 'street shooting' on different days, but similar lighting in the MOA
with both the 50-135 & 77ltd:
77ltd, f2.4, ISO 200, pretty tight crop:
77ltd, f2.4, ISO 200
50-135 at 58mm, f/4, ISO 400:
50-135 at 135mm, f/3.5, ISO 400
So as you can see, both excellent for that purpose, and the resolution of the
77ltd allows for cropping even out to a 200mm equiv without too much
IQ dropoff.
But to me, even though the 50-135 is mind-blowing, the 77ltd just does have
that old black magic:
(all 3 f/2)