p.1 #3 · Looking for a Lens for the Pentax K100D...
i'm not sure quite honestly...
i think, maybe if you or anyone could suggest a couple lenses at either range of the spectrum then i'll let him decide. ? i used to have a k100d but know nothing about pentax version lenses and what's good and what's not. so i thought i would ask
p.1 #4 · Looking for a Lens for the Pentax K100D...
there are limited choices from Pentax itself. the DA 50-200 is an excellent small zoom but 200mm is on the short side. the 80-320 is no longer made but does a decent job. both are inexpensive. then there are 3rd party lenses including the rebadged Tamron 18-270. frankly, his limits are going to be the body itself. he's going to have to spend a lot of time practicing technique to make up for the poor AF speed. the higher end Pentax lenses like the 200/2.8 and 300/4 are expensive. i think he will want to have something close to 300mm.
p.1 #8 · Looking for a Lens for the Pentax K100D...
The k100d and sports are pretty much like oil and water, they just dont mix well. If he has a K100d super then the best option are the above mentioned DA200 and DA300. The AF of the K100d is slooooooooooooow. If he is good with predictive manual focus then he can try to look for a Tamron 300 f2.8 adaptall.