Laowa Aksen 17.5mm f/1.7 5-10X Ultra Macro APO (L-Mount)

The Aksen 17.5mm is the higher-power half of Laowa's parfocal macro pair: it magnifies from 5x to 10x life size, beyond the 5x limit of earlier close-up lenses. An internal zoom changes magnification while the barrel length and the 22.48mm working distance stay fixed, so a subject in focus at 5x stays in focus at 10x without moving the camera or the lights.

The full-frame APO design uses 17 elements in 12 groups, including five ED and three ultra-high-refraction elements, behind an 11-blade diaphragm that runs from f/1.7 to f/5.6. A narrow front snout leaves room to work at such a short distance, and a coaxial version ($100 more) adds a beam splitter that takes a small USB light to shine along the lens axis. It is fully mechanical, with no focusing mechanism, no infinity focus, no filter thread and no electronic contacts; the L-Mount version is one of eight photo mounts.