Would be interesting to see what the minimum focal distance is with converter for the Bigma. I read that w/o converter it is 300 cm at 500 mm, which is rather long. As I don't do much bird photography this lens would be too heavy for me to carry around and to keep in the air. I got a Tamron 70-200/2.8 that is also useful for shots of insects and flowers, however I leave it at home because of its weight. Henk Op 2025-06-09 om 09:09 schreef Larry Colen: >> On Jun 8, 2025, at 11:46 PM, Henk Terhell<henk.terhell@gmail.com> wrote: >> >> I have no experience with the Bigma, but I think you loose some stops with extension tubes. > Yeah, you do, probably related to the delta in equivalent crop area. I would guess that at an extra mag factor of 1.4 linear, you would lose a stop. > >> For me, indeed the HD 55-300 PLM is most convenient for fast moving insects. It has fairly fast focussing, is light weight and has a minimum focus distance at 300 mm (450 eq.) of 95 cm. Therefore most of the times I leave my Tamron 90/2.8 macro at home. >> Here two shots (somewhat cropped) of bumblebees taken with the 55-300 PLM yesterday. >> https://flic.kr/p/2r9AvQ2 >> https://flic.kr/p/2r9BtUV > Those are great shots. > > I suppose I could calculate magnification by photographing a ruler at minimum distance and dividing by the width of the sensor. > >