What's the deal Pentax?
I haven't been super pleased with the Tamron 300mm f/2.8 + Pentax AF 1.7x combination. It just wasn't sharp -- but then I wasn't sure what to expect anyway with this setup.
My K10D has that damned back focus crap -- but I calibrated it with my FA 50mm f/1.4 to +60um in the debug menu -- which made the FA 50mm uber sharp and fixed my wide angle back focus problems with my 18-250mm.
I was pleased. Now, I started playing with the focus adjustment for the Tamron 300mm f/2.8 + Pentax AF 1.7x combination. It likes -140um! Gawd.
I don't get this crap -- either the image is at maximum contrast or it's not, or the camera doesn't have enough contrast to focus. . . but apparently it's not that simple to understand.
Anyway, check out the below picture with the Tamron 300mm f/2.8 + Pentax AF 1.7x combination when it's properly adjusted -- head is full pixel.
That's sharp, too bad I need to get in the debug menu every time I want to use this lens.