No official test. You zoom in 105 cm to max. Set manual your focus. Than you make a hole on something around 1cm. You put a white paper behind and use a toch to create that light. Than on viewfinder you can see and use that 3 screw to calibrate to ge...
Recently changed apeture unit as cable broke. After i got smudgy and not clear image but focus was on right place. So there is 3 tiny screw to calibrate that chromatic abberation. You need a pinhole with back light to see that shape. You will never a...
