Konica F mount specifications
Mount type: Bayonet (lens release on camera)
Flange focal distance: 40,5 mm
Film format: 36mm x 24mm (‘Full frame’)
Mount communication: see below
Information on the Konica F mount:
The Konica F mount is the relatively short-lived (1960–1965) predecessor to the more long-lived Konica AR mount (1965-1987). The Konica F and AR mounts are not in any way compatible, even though the AR mount initially inherited a lot of the Konica F mount’s lenses.
That said, there are actually two variants of the Konica F mount: One version for use only by the Konica F SLR, and another used by Konica SLR’s until the advent of the Konica AR mount in 1965 – I’ll refer to these as F-coupled and F-uncoupled.
If this seems a but quirky, it is. Konica launched its flagship SLR, The Konica F, in 1960, after 7 years of development. Although only some hundreds were manufactured (guesstimates range between 600 and 1500), the Konica F is today one of the most collectible cameras out there, and not only because of its relative rarity, also because (for 1960) the Konica F was leagues ahead of its time: Fully cross-coupled match-needle metering (not TTL), 1/2000 s shutter speed, 1/125 flash sync…
The next variants, named FS, FSW, FP and FM, did away with the integrated, cross coupled metering and instead relied on a more pedestrian approach (sunny 16 or hand-held light meters), but still enabled framing and focusing with fully open aperture.
While only four lenses were ever introduced for the Konica F, the raw specs of those lenses (35 mm f/2; 52 mm f/1.4; 85 mm f/1.8; and 135 mm f/2.8) are impressive. The lineup of F-uncoupled lenses on the other hand not only contained four lenses of identical specs (focal length and max aperture), but gained another 8 primes, including a monstrous 800 mm super-tele.
While many sites class the F-coupled and F-uncoupled as minor variants of one mount, and seem to assume that the F-coupled lenses were physically similar to the later F-uncoupled lenses, there is reason to doubt this: Not only would the Konica F not be able to meter with F-uncoupled lenses, there seems to be a minor difference in the implementation of the mount’s aperture stop-down linkage, leading to that later Konica Fx cameras might have trouble using F-coupled lenses. Moreover, while some sites (such as Andreas Buhl’s otherwise impeccable resource) seem to assume that the identical-spec (e.g. 52/1.4; 35/2) F-coupled and F-uncoupled lenses were of similar design (design, size, weight, etc.), there are also sources that point in a different direction.
Alas, the existing documentation on the Konica F and F-coupled lenses is so thin, that it’s impossible to know whether the F-coupled 72 mm filter 35/2 and 49 mm filter 52/1.4 shown on Camerapedia were indicative of the entire range of F-coupled lenses, or whether these were very early, pre-redesign samples.
Demise of the Konica F mount
The 1960’s were a decade of feverish development in the Japanese SLR scene, and it was quickly obvious that Konica had plans (such a the 1965 Konica Auto-Reflex – The first SLR with automatic exposure control) that could not be implemented within the narrow boundaries set by the F-mount’s Lens-Body communication. Hence, the Konica F mount was abandoned in favour of the Konica AR mount (see more here). Even so, many of the lens designs from the lineup of F-uncoupled lenses were retained.
Adapting Konica F lenses
The Konica F shares very little with its successor the Konica AR mount: Beside a handful of lenses that were carried over, the only other commonality is the (for an SLR) short flange focal distance of 40,5 mm. That restrictive flange focal distance has for 40+ years, precluded Konica F lenses from successfully being adapted to other SLR’s than the Konica AR system (Konica for some time offered an adapter ring to allow using Konica F lenses on Konica AR cameras, but these adapter rings are today worth their weight in gold).
Since the advent of full frame mirrorless cameras, and with the increasing interest in adapting legacy lenses, Konica F lenses have accrued some interest, but (as of my last check) the only manufacturers of Konica F to mirrorless adapters are enterprising individuals (search eBay). I have one such adapter, and while it works, it is decidedly fidgety (changing the lens seated on the adapter takes some minutes and securing the lens to the adapter necessitates an allen key). Therefore, unless you’re one of the lucky owners of a Konica F to Konica AR adapter ring, adapting Konica F lenses to your mirrorless camera is not a smooth operation 1.
OTOH, based on the imagery my 52 mm f/1.4 (F-uncoupled) provides, it might be a journey well worth taking.
1 This is a somewhat sad state of affairs, as the Konica F mount does not present a real challenge (lenses have aperture rings and focus rings, mount is neither outsized nor hideously complex).
More information on the Konica AR system:
• Andreas Buhl’s fantastic site
• Konica F on Urs Brunner’s site
• Konica F on camerapedia