| Latest Review Posted | Sigma DC OS HSM 18-50mm F2.8-4.5
What a bargain! One of the true values for any Pentax DSLR. This Sigma provides better than average image quality and is a great upgrade from the kit lens. It is slightly faster at both the wide end and long end than the kit zoom. This Sigma also has a nice quiet auto focus motor with an optical stabilizer. The coolest thing is the internal zoom, which means that the lens doesn't extend when zooming in and out. Had never seen an internal zoom lens priced at $200 before. In fact, I didn't even know that this lens had an internal zoom until I got it. It was a very very very pleasant surprise.
The lens is a little bigger and heavier than I expected for a 2.8-4.5 lens with limited focal range of 18-50mm. The Tamron 17-50 with constant f2.8 is both smaller and lighter. On the other hand, this Sigma does have an internal motor and optical stabilizer (the Tamron doesn't), which somewhat justifies the larger size and heavier weight. The Pentax 18-135 has a more versatile focal range and an internal motor, but is also smaller and lighter than the Sigma 18-50.
Auto focus speed doesn't seem faster than either the kit lens, the Tamron 17-50 or the Sigma 17-50. Out of the four, the Sigma 17-50 might be the fastest, but just barely faster. The Pentax 18-135 is faster than the other four lenses. I don't seem to have any back or front focus issue with this Sigma.
Image quality is better than average, and slightly better than the Pentax 18-135 in my opinion. You can focus about as cl... |
