Originally posted by Echo.Delta I am leaning towards purchasing the SMC Pentax-DA* 16-50mm F2.8 ED AL [IF] SDM, but I wonder if it's too crazy/ridiculous even thinking about pairing with an entry-level DSLR like the K-50. Can the K-50 take full advantage of this lens' quality?
Certainly it can.
However, one thing to bear in mind with that lens
is that it has had a history of failure of the rather weak motor
that drives the AF mechanism internally.
The internal motor in the DA 18-135 is not so advanced technologically,
but seems to be more robust.
There is also a new 16-85 lens which may not be as good optically as the DA * 16-50,
but which will give you a bigger range, and which has the more robust internal AF drive.