China ton

First of all:
800mm focal length are nothing to photograph out of his hand. I do not mean that you hinbekommt no short exposure times for blur-free images. With 800mm focal length make maintenance even the smallest movements of the hand noticeable, so that it is almost impossible to accurately focus. This also applies if you have retrofitted the camera with a sectional image slice.

Negative for me:
- At the Pentax-variant, the distance scale is not up, but right on the side
(A problem of the T2 adapter?)
- The complete range is 3 m to infinity is crossed in a quarter of a turn
(A fine focusing is not possible)
- The focusing ring is rather sluggish
(You have the T2 adapter firmly tighten)
- The large case diameter makes use of 410PL-exchange plates from Manfrotto difficult because the locking lever abuts