PL upgrade of LOMO prime spherical lens with Konvas-2M lens housing with outside slide pins. OST-19 lens mount.

A some LOMO prime lenses have version of lens housing with outside slide pin.

This is LOMO 50 mm T2.2 35 OKS-1-50-6 prime lens.

The PL mount version of lens housing upgrade ask of installation new lens housing parts.

The lens after PL upgrade.

LOMO 28 mm T2.4 35 OKS-4-28-1 prime lens have OST-19 mounted version of lens housing with outside slide pin.

The outside view of original lens.

LOMO 28 mm T2.4 35 OKS-4-28-1 prime lens after PL mount upgrade of lens housing.

To have geared focus control and 80 mm front adapter.

LOMO OKS-4-28-1 optical block have short back focal distance, 23.06 mm only,

That's why, 35 OKS-4-28-1 prime lens have dimension limitation.