Olympus OM-1

Maitani's whole pitch was that the SLR had gotten fat, and the OM-1 is the proof. Pick one up after a Nikon F2 and your wrist files a complaint. Olympus shaved the full-frame 35mm reflex down to something close to a Leica's footprint while keeping a full mirror, a real meter, and a bayonet system behind it, and for a while in the 1970s every other SLR on the shelf suddenly looked like a brick. That is the thing the OM-1 is remembered for. It made the full-size SLR genuinely small, and it did it more convincingly than anyone had before.

The viewfinder is the surprise. It is enormous and bright, magnification up around 0.9x with a big eyepiece, which is rare for a body this size, and the split-image patch ringed by its microprism collar snaps focus into place cleanly even in dim rooms. The control layout is the other oddity. Shutter speed lives on a ring around the lens mount, not a top dial, so your left hand sets aperture and speed together without leaving the lens. It feels strange for about an hour and then feels obviously correct. The meter is a center-weighted CdS cell, match-needle, a single line in the finder you zero by twisting. No battery needed to fire the shutter, only to meter, which is the whole point of a mechanical body.

The shutter is cloth, horizontal, running from a full second to about 1/1000, flash sync at 1/60. It is quiet for an SLR of its era, a soft clack rather than a bang, and the mirror was deliberately damped because Maitani hated the slap. You can shoot it slow and handheld in a way you cannot with a Pentax 6x7.

The honest problem is the battery. The OM-1 was built for the 1.35V PX625 mercury cell, which is banned now, and the match-needle was calibrated to that voltage. Drop in a 1.5V alkaline and the readings drift as the cell ages. People work around it with a Wein zinc-air cell, an MR-9 adapter, or by recalibrating the meter, but plenty of bodies in the wild simply read wrong. When that meter goes vague, an incident or spot reading from the Zone Light Meter app is how you place exposure cleanly. It becomes the meter the body was supposed to have before the chemistry changed underneath it.

Who carries one. Travelers, students, anyone who wants a mechanical SLR that does not punish them for walking ten miles with it. The Zuiko glass is part of the appeal. The 50mm f1.8 is sharp and cheap, the 28mm and 35mm are small and lovely. Today an OM-1 sits in the affordable-classic tier, cross-shopped against the Pentax MX and the Nikon FM, and it usually wins on size and finder. Watch for foam light seals turning to tar and a prism that can fog from old foam off-gassing. Get one with a clean finder and a serviced meter and it will outlast you.