I have been playing with 3 1000mm lenses on my K10D.
MC MTO-11CA 10/1000 (russian maksutov mirror lens)
SMC PENTAX REFLEX 11/1000
SMC PENTAX 1:8 1000mm
And these are not very common, so maybe others would like to see how they perform.
All on a sturdy tripod : Berlebach UNI6 (no head, but I used the leveling mechanism for aiming instead)
Because it takes some time to swap these lenses (and mirrors) the lighting conditions are unfortunately not exactly the same.
My test object is a 'Bobcat' on the roof of a building.
This is the uncropped frame :
The grid and the bright sky (white sunlit clouds) behind it, will make it extra tough for these lenses.
Here 100% crops :
1 MC MTO-11CA 10/1000 :
2 SMC PENTAX REFLEX 11/1000 :
3: SMC PENTAX 1:8 1000mm @ F11:
4: SMC PENTAX 1:8 1000mm @ F8:
5: SMC PENTAX 1:8 1000mm @ F8 + Yellow K2, and the color adjusted afterwards:
Anybody doubt the need of APO/ED tele lenses ?
And the air turbulence is probably a more resolution limiting factor than the lenses.
George