Alpine Swifts

swifts are always a test of camera auto focus abilities -- and I like swifts -- expecting it to be hot I made the decision not to take the 2x converter with me and stuck with the 400 DO2 and the 1.4x mark 3 with the Canon 5D4 -- the 5D4 allows generous cropping and has superb image quality  -- I have finally found my ideal camera lens set up after spending far too much on gear in the last few years --  on occasions I took the 1.4x converter off and worked just witht he 400 and that is something I should do more often --