Olympus Zuiko Auto-T 100mm f/2

A fast 100mm that focuses to about 70cm and renders backgrounds like melted butter: that is what OM shooters are actually buying here, and they pay dearly for it. The Canon FD 100mm f/2 is a hair smaller and lighter, and usually cheaper, so the size argument does not go the Zuiko's way. At roughly 520g and a 55mm filter thread, this is not the dainty member of its class. The pull is optical. Olympus put ED glass in a fast tele at a time when most f/2 100s of the late seventies were soft wide open and nervous in the out of focus zone, and this one is neither.

Wide open it is sharp across most of the frame in a way its contemporaries usually were not, with the corners already strong at f/2 and the last bit of edge bite arriving between f/4 and f/5.6. The rendering is the reason it has the cult following. Backgrounds dissolve smoothly, specular highlights stay round instead of going to hard-edged discs or onion rings, and the falloff from the focus plane is gradual rather than busy. This is the lens you reach for when you want a head-and-shoulders frame on Tri-X or Portra with the subject clean against nothing behind it. Skin tones come back neutral, contrast is moderate rather than punchy, and the overall look sits closer to a Planar portrait lens than to the high-microcontrast Leica school.

Flare control is good without being bulletproof. Shoot into a low sun without the dedicated hood and you can pull veiling haze across the frame, which on a high-contrast color slide will lift and mute the shadows. The 55mm thread, larger than the 49mm on the slower OM Zuiko 100mm f/2.8 and larger than the Canon's 52mm, is just the price the fast aperture and the ED element extract from the barrel. Nobody designed this to be the smallest 100 in the bag. They designed it to draw a certain way, and it does.

The honest weakness is what a clean copy costs now. This was never cheap new, and the OM crowd treats it as a grail, so good examples routinely outprice a comparable Canon or Nikon 100/105 by a wide margin. You are paying for rarity, collector status, and the f/2 ED optics, not for a lens that is smaller than the alternatives. Only you can decide whether that rendering is worth the premium over the optically excellent Nikkor 105mm f/2.5, which sells for a fraction and gives up very little on a portrait.

People still buy it for one reason beyond collecting: it pairs with an OM-1 or OM-4 into a portrait kit that meters down to almost nothing. The OM-4's multi-spot system and a fast tele were a documentary and editorial pairing for a reason. If you are running an external meter, wide open f/2 in dim evening light is where you have to be deliberate. Spot the shadow you care about, let the highlights fall, and the Zone Light Meter app's spot mode keeps that call honest when you are working off a single face. The practical catch is the close range. At 70cm and f/2 your depth of field is paper-thin, so nail the eye and accept the ear going soft, or stop to f/2.8 for both eyes on a three-quarter turn. For a single subject against open space, few fast teles of the manual era are more pleasant to shoot, and the only real argument against it is the second-hand sticker.