Camera Labs

i'm looking for a good lens for my new pentax k10d, i have got the 16-45mm lens as my kit lens, since i do lot of outdoor/wildlife photography, i'm looking for a good lens which can zoom up to 400mm (35mm eqiv).
does anyone own a 50-500mm? does it feel rather heavy(1.8kg)? does the HSM works on it with pentax? can the SR on k10d make any effect? (like 2 stops of different) and is there any other chioce i could go for, like the 135-400mm?

by the way, loves the k10d, and thanks for the review on it too, it was really useful.

Well, in your case the 100-300 is certainly a very good option. See this test. I have not heard the same of the 50-500mm
But it is not cheap (>1100EUR!)! On the other side, with an F4.0 lens you can even use a 1.4x tele-converter to make it a 140-420mm/F5.6 lens!
So you certainly have enough at the long end...

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Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews, My Pictures, My Photography Blog
D800+assorted lenses