Sigma 400mm f5.6 - vintage lens review
The lens is made out of metal, it weights 750g, it is 20,3cm long and it has an external diameter of 82mm, with a 72mm front thread. It has a built in sunhood lined with opaque material and when extended it brings the total length to 25,5cm The iris had 6 blades, the aperture is clicked and it goes from f5.6 to f32 with half steps. The focusing ring is rubberized, it turns 130 degrees and minimum focusing distance is 4 meters. My copy comes on a Pentax K mount with a flange distance of 45,46mm. At this point I would usually mention how the lens balances on the camera, but in this case it is the camera that balances on the lens. Thankfully it has a tripod mount on the collar, which also allows the lens to spin, so you can change the orientation of the camera while on sticks. The focusing ring is jut in the right position to use it even when hand holding the system. Wide open images are pretty soft all over the frame and you have to stop it down to f11 to get good sharpness...