This is a document about the 35mm SLR Hybrid Shutter Control System, which provides exposure automation and the ability to use all shutter speeds even if the batteries fail. In Aperture Priority Auto mode, shutter speeds are controlled electronically, while in Manual mode, all shutter speeds are mechanically timed and do not require battery power. Other features include classic 60/40 Center Weighted metering, match needle exposure display, versatile exposure extras such as Auto Exposure Lock and Exposure Compensation, rugged body construction, and TTL flash metering system.
The FM3A combines a hybrid shutter system that works mechanically without batteries in Manual mode and electronically in Aperture‑Priority mode. It offers classic 60/40 center‑weighted metering, TTL flash control, and a bright split‑image viewfinder with 0.80× magnification and approximately 93% coverage.
The manual details the camera's construction, interchangeable focusing screens, shutter speed and ISO ranges, battery options, and accessories such as the hot‑shoe and motor‑drive coupling. Full specifications, including dimensions, weight, and lens mount, are listed for reference.
| Shutter speed range (Manual mode) | 1/4,000 sec. to 1 sec., B (Bulb) |
|---|---|
| ISO range (DX‑coded film) | 25 to 5000 |
| Lens mount | Nikon F mount |
| Viewfinder coverage | approx. 93% |
| Dimensions (W × H × D) | 142.5 × 90 × 58 mm |
| Weight (without batteries) | Approx. 20.1 oz. |
Manual mode provides mechanically timed shutter speeds from 1/4,000 sec to 1 sec, plus a Bulb setting.
It uses a TTL 60/40 center‑weighted full‑aperture metering system with silicon photodiodes and a metering IC circuit.
The camera can be powered by one 3 V CR‑1/3N lithium battery, two 1.55 V SR44 silver‑oxide batteries, or two 1.5 V LR44 alkaline batteries.