Found a need for 800mm
Testing lens conmbo's to reach this number.
Tokina 400mm atx sd f5.6, plus Pentax 2x-s TC
Interesting note, bean bag stabilizes better that tripod ????????
Does this lens have a tripod collar? If your camera is mounted to the tripod, I imagine a bean bag could be better; lens + converter could really affect the center of gravity.