Leica's classic wide-angle — the Summaron 35mm f/2.8 with spectacles for M3 compatibility.
The Leica Summaron-M 35mm f/2.8 with Spectacles is a classic Leica wide-angle prime. The 'spectacles' are auxiliary optics that attach to the rear of the lens, modifying the M3's high-magnification viewfinder to show 35mm framelines. Without spectacles, the M3 has no 35mm frameline. The Summaron was the standard 35mm for early M cameras.
Optical performance is good for the era — the Summaron provides respectable sharpness with the warm Leica character. The f/2.8 is modest but adequate for the era's film speeds. The spectacles enable 35mm framing on the M3 — the most common early Leica M body. Later M cameras have 35mm framelines built in and don't need spectacles.
Leica M mount with spectacle attachment for M3 compatibility. Filter thread is 39mm (E39). Weight is approximately 155 grams — very compact. Build quality is classic Leica precision. The spectacles are specific to the M3 — they are not needed on M2, M4, M6, and later bodies which have native 35mm framelines.
Available at moderate Leica prices. Check the spectacle attachment and rangefinder coupling. The spectacles add M3 compatibility value. Without spectacles, the lens works on any M body but M3 users lose the 35mm frameline. A classic Leica wide-angle with historical significance. The Summicron 35mm f/2 is the faster alternative.