Olympus F.Zuiko 40mm f/1.7 (35 RD fixed)

Olympus put this lens on the cameras it wanted taken seriously. The 35 RD arrived in 1975 as the fast, top-tier rangefinder in Olympus's pocket-camera line, above the smaller 35 RC, chasing the idea Yoshihisa Maitani had worked since the Pen: a real camera that vanishes in a coat pocket. SLRs were the serious tool of the decade and getting big and dear, so the RD answered with a fixed 40mm f/1.7 over a leaf-shutter body, shutter-priority auto, and a coupled rangefinder. The same six-element F.Zuiko optic showed up on the program-auto 35 DC, the point-and-shoot sibling, so this was Olympus's best small-camera glass of the era. The F in F.Zuiko is the company's shorthand: F is the sixth letter, so this is a six-element design.

What that formula does on film surprises people who paid pocket change for the body. Wide open at f/1.7 it is good, not glowy. There is a touch of softness and some edge falloff, but the center is already usable, which is the whole reason you carry an f/1.7 compact instead of a slower one. Stop to f/4 and it is genuinely sharp across most of the frame. By f/5.6 to f/8 the corners catch up and it resolves with a bite that reads more like a good SLR prime than anything you expect from a fixed lens. Contrast is healthy, color reads neutral, and flare stays controlled for a lens this old as long as you do not aim it into the sun.

The 40mm length is what makes it work. Wider than a fifty, tighter than a thirty-five, it frames a street scene or one person at arm's length without backing you into traffic. Bokeh is calm and unfussy, smoother than a small fixed lens has any right to be, never swirly or nervous. Nobody buys an RD to chase background blur. They buy it because the lens is fast and small and resolves cleanly, and because the rangefinder patch nails focus in dim light where an autofocus compact would hunt.

The leaf shutter is the metering quirk worth holding onto. Because it sits inside the lens, flash syncs at every speed right up to 1/500, so you can drag a bright background down with a fast shutter and still pop a fill flash at f/1.7. For available-dark frames the RD gives you Bulb plus timed speeds down to 1/2 second, enough for plenty of low-light work off the dial. Set Zone Light Meter to f/1.7, meter off the brightest detail you need to keep, and let the shadows fall. The RD reads a single CdS cell on the front of the lens and meters for the whole scene, so a face against a dark room can push the auto exposure long and blow it out.

The honest catch is the meter only couples in shutter-priority auto. You can set aperture by hand across the full f/1.7 to f/16 ring, but nothing reads it for you in manual, and that CdS cell is fifty years old now. Plenty read low, stick, or die, and a dead meter here means guessing or carrying a handheld. Cross-shop it against the Canonet QL17 GIII, the Konica Auto S3, and the Yashica Electro 35. The Canonet is the safer buy on numbers built. The Olympus is the one to grab when you want the 40mm angle and a lens that holds its own against any of them, clean copy for clean copy.