Shelyak Alpy Barlow Lens

The mechanical backfocus of the Alpy 600 (distance between Alpy 600 and your camera CCD chip) has to be between 10 and 20mm. If you have a camera with a bigger backfocus (it is the case for cameras having a wheel with filter), or wish to use a Digital camera (DSLR), this barlow increases the backfocus to a range of 44.7 to 55.2mm.

The Barlow is installed at the rear end of the ALPY 600 (camera side).

With standard M42x0.75 camera adapter, backfocus range is 44.7-55.2mm.