Pekka Buttler, July 2025.
Basic Information on the M47 mount:
First, the M47 mount is not – strictly speaking – a lens mounts as there has never been a camera that uses this mounts. Instead, the M47 is an intermediate mount. The purpose of intermediate mounts is to allow third party lens manufacturers to easily make their lenses usable on a wide range of camera bodies, simply by attaching a suitable adapter to the lens.
M47 mount specifications and identification
Mount type: Thread mount (M47x1)
Flange focal distance: 55 mm
Sensor Size: 36,0 mm x 24,0 mm (Full frame)
Mount communication: none
Left: M42 to Minolta SR adapter ring.
Characteristics of a M47 mount:
[47 mm diameter threads with a thread pitch of 1 mm (M47×1)
(no camera–lens communication)
Another typical characteristic of M47 adapters is that they feature a set screw/grub screw, the idea being that you thread the adapter ring onto your lens, then secure it in place with the grub screw.
The M47 intermediate mount.
Unlike more well-known intermediate mounts (such as the T/T2 mount, the T-4/TX mount or the Tamron Adaptall mount), the M47 mount is relatively obscure and does not have a generally established name. Instead it is sometimes referred to as the T-thread (risk of confusion with T/T2 mount), Tokyo Koki mount (because many lenses that have this mount also say Tokyo Koki on the name ring).
The mount was indeed invented by Tokyo Koki Seisakusho (today Tokina) and it was used on a series of lenses containing one 35 mm wide-angle and a range of tele lenses from 105 mm to 800 mm superteles. These lenses were manufactured for sale primarily through rebranders (including Accura, Hanimex, Sears, Soligor, Spiratone etc.). Simultaneously, this coincided with the period when Tokyo Koki first started playing with the idea of launching its own brand (see the JAPB company profile on Tokina for further details) and many of these lenses can also be found using names such as (simply) Tokyo Koki or some combination of Tokyo Koki and Minetar (Likely Tokyo Koki toyed with adopting Minetar as a trade name1) or Tokyo Koki and Tokina (even LUCKY-Tokina)
One problem with the M47 mount (as well as many other early interchangeable mounts such as the T/T2 mount) was that it did not in any way facilitate camera-lens communication. In the age of manual and preset apertures that was enough, but as auto aperture started becoming the norm, Tokina had to develop a new intermediate mount (the T-4/TX mount).
Note please: There are some accounts online (which I have not been able to confirm) that some of the earliest Tokyo Koki interchangeable mounts were not 47 mm threads, but 49 mm threads (but that the logic of the mount was otherwise the same). If you have such a lens, please be in touch or leave a comment.
Adapting M47 lenses
If you intend to adapt your M47 lens to a SLR…
There are M47 adapters available to many of the early SLR, including (at least) M42, Minolta SR, Miranda M44, LTM, Canon FL/FD, Exakta, and Petri FT. These adapters allow you to use the M47 lens as a manual focus manual aperture lens.
The lack of Olympus OM, Pentax K and C/Y adapters indicate that these lenses disappeared well in advance of the introduction of these systems. Interestingly, I have not been able to find either a Konica AR or Nikon F adapter.
If you intend to adapt your M47 lens to a mirrorless camera
There are (as of this moment) no M47 adapters to any mirrorless system available. This basically means that you will have to:
a) mount one of the above mentioned M47->SLR adapters on your lens, then
b) mount the lens on your SLR->Mirrorless adapter.
- The other alternative is that Minetar is an independent, short-lived rebrander who agreed on co-branding with Tokyo Koki (as most Minetar lenses clearly also mention Tokyo Koki). ↩︎