Okay, I got at Pentax DA to replace my Tammy 70-300 as I found there to be a bit much CA on the long end of the Tamron.
I did my first real world test of the Pentax today and most of the shots seemed to be front focused. Can't re-create it in controlled environment ... I guess that's good ..
So, I decided to see how ut did against the old one.
Setup is against a brick wall that's about 15 meters from my bedroom window, set at a nice angle (for the focus test). Cloudy flat light, tripod, remote trigger, 2sec timer (for mirror lockup).
Imported in lightroom 2 - default setting, except sharpen=0.
100% crops from the center of the shot - focus was on the white vertical bar in the center.
260mm f/5.6 - Tamron, then Pentax:
The Tamron seems sharper.
300 f/5.6 - Tamron, then Pentax (at 5.8):
Again, the Tamron seems a bit sharper. Less so then at 260.
300 f/8.0 - Tamron, then Pentax
Pentax seems quite a bit sharper here.
So the Tamron is sharper wide open, but doesn't get much better stopped down at 300. Sunny day, bring the Pentax.
Last edited by tcdk; 10-31-2009 at 07:37 AM.
Reason: Add conclusion..