Orion-15 28/6 on NEX5N

Орион-15 (Orion-15) 28mm f/6 lens, 4e/4g, single-coated, LTM, ca. 1950 mounted on a Sony NEX-5N via an NEX-5N adapter. It's a tiny lens that weighs only 65 grams.

The Orion probably descends from Robert Richter's 1934 Topogon design, though it is sometimes said to be based on a Double-Gauss aerial telephoto lens that Zeiss made for the Russians prior to WWII. That said, the Orion's 1944 production start predated that of the famous 25/4 Zeiss Topogon by six years.

I would describe the Orion as a very slow, low-distortion, low-contrast, high-resolution lens. CA and geometric distortion are virtually non-existent. Its sharpest aperture in my hands is f/11 which confirms others' experiences.

I kept postprocessing to a reasonable minimum to show the len's performance without a lot of embellishment. I used dodging, neutral SEP2 conversion, and color filtration on all the images and SEP2 levels on one.

Softer at f/8 than at f/11

Flare is not too bad for a lens of this vintage. I used SEP2 levels to remove some of the veiling flare.