Pentax's first autofocus SLR — the SFX, built-in flash, KAF mount, 1987.
The Pentax SFX is a 35mm autofocus film SLR from 1987, sold in North America as the SF1. It was Pentax's first autofocus SLR to reach production and is often cited as one of the earliest SLRs with a built-in retractable flash integrated into the pentaprism housing. It uses the Pentax KAF autofocus version of the K bayonet and was marketed under the Pentax name in the UK.
It is a 35mm single-lens-reflex camera using the Pentax KAF autofocus mount, with in-body autofocus driven through the lens coupling and through-the-lens metering. The electronically-timed vertical focal-plane shutter reaches a top speed of 1/2000 with flash sync at 1/100. Exposure modes include program, aperture-priority, shutter-priority and metered manual. A built-in motor advances the film, and a pop-up flash is integrated into the top housing. All functions are electronic and the camera is fully dependent on its battery.
The SFX suits users wanting an early autofocus SLR with a built-in flash for general, family and travel photography, and it accepts the full range of K-mount lenses in manual focus as well as autofocus optics. Its autofocus is slower than later Pentax bodies, and its size is larger than the compact manual M-series, but it brought program automation and autofocus into a single integrated body.
As a used buy, inspect the foam light seals and mirror-damper foam. Because this is an electronic autofocus body, test the autofocus drive, the built-in flash pop-up and the LCD or viewfinder display carefully, as ageing electronics and displays are the main concern rather than a mechanical shutter. Confirm the film-advance motor winds cleanly, the meter and exposure modes respond correctly, and the shutter fires evenly. The camera will not work without a good battery, and battery-door and contact corrosion should be checked.