Originally posted by audiobomber I used the 16-45mm for a few years and upgraded to the Sigma 17-50. Your statement about flare is overstated, that has not been my experience at all. It's no DA 15mm, but it's a zoom, not a prime. I think the 17-50's tendency to expose to the right, vs. the 16-45's tendency to underexpose by half a stop may be misleading some. All around IQ on that lens is spectacular (for a zoom).
Many thanks for the information, Dan. Much appreciated! The Sigma 17-50/2.8 would suit me really well as I have a whole kit of 77mm filters from my Nikon days.
I based my opinion about it's poor flare resistance on several websites. First on the reviews of users on Juza. It's an Italian forum which I frequently visit. Several of the users complain about the poor flare resistance of the 17-50 so I removed the lens of my list knowing the flare would certainly annoy me. Here are the reviews :
Sigma 17-50mm f/2.8 EX DC OS HSM : Specifications and Opinions | JuzaPhoto
Also the pictures shown on Lenstip didn't convince me, especially at 17mm F8:
Sigma 17-50 mm f/2.8 EX DC OS HSM review - Ghosting and flares - LensTip.com
And then there is of course the comparison with the Pentax 16-50 and Tamron 17-50 on this website where it is stated that "
The Sigma performs worst of all, often overexposing and losing significant contrast with the sun in the frame, and usually showing really ugly flare patterns."
Probably, as adviced by several members, it is best to have a prime like the 15/4 in your kit in combination with the DA35 or 20-40. This topic is really useful for me as only now I'm starting to understand the advantages of a combination of a zoom together with the Pentax primes. Thanks to you all!