Originally posted by augustmoon Sigma 100-300 is a terrific lens, and is very very sharp. I doubt that the Pentax will be any sharper. The Sigma has longer reach, which is important factor for getting a super tele zoom in the first place, and they are both F4, and the Sigma is tons cheaper. The Sigma FL matches up more closely with the 50-135 if you wanted to have better coverage. In the States you can pick up a 50-135 and the 100-300 for just around the price of the 60-250. I just don;t understand the Focal Length of the 60-250, and it being an F4, when Pentax already released the 50-135 at 2.8. Seems like they would go with a 100-whatever or something at 2.8 or something cheaper.
Hi Brian. The primary reasons I can see for Pentax to maintain the f4 aperture would be to continue with compact sizing and to manage price. The range seems to simply try and edge past the classic 70-200 margins of general zoom, but this is all curiously comprimised with the pricing being near or at that of f2.8 zooms from other makers.
Generally speaking, I'd say for weather seal alone as a distinguishing advantage, paying this premium is a lot to ask at its spec considering the competition (further, it may or may not work on a future FF body and will probably follow suit with modern Pentax releases being manufactured off-shore in the Vietnam plant leaving QC suspect). I had considered one myself in past as a high quality, general telephoto option as my need for this focal range is varied and sporadic, yet where quality is still expected.
Value for money was a Pentax forte and one of the reasons I started there, but that is drying up instantly. To illustrate (as many before me), I was able to purchase Sonys just released 70-400/4-5.6G flagship zoom for 1650CAD. The classic 70-200/2.8G is available for the same price. They also offer a lighter 70-300/4.5-5.6G for 800CAD. Note these are all Sony 'G' lenses, equivalent to the DA*, robust, solid performers - yet guaranteed full frame and made in Japan.
Obviously Pentax need to charge more as everyone does to make ends meet in the current market, but they seem to be swimming a little close to the mouths of larger fish at this price point.