The Adaptall System
A Short History
Tamron was founded in 1950 as Taisei Optical Equipment Manufacturing making cameras and binoculars.
In 1958 they introduce the T-mount system (T for Taisei) with their 135mm ƒ/4.5 #280, which, along with subsequent T-mount lenses, is able to be used with the various cameras being produced by the new japanese camera manufacturers. The T-mount uses a 42x0.75mm thread to couple the lens to the mount, which solely holds the lens to the camera with no provision for aperture coupling. In 1961 the first affordable zoom lens, Taisei's 95-205mm ƒ/6.3 #910P is released for the T-mount.
In 1966 Taisei introduces the Adapt-a-matic series, which imroves upon the T-mount with an automatic stop-down linkage. The adapt-a-matic system was modified and improved throughout its short production run, with coupling for open-aperture metering being introduced partway through, as well as aesthetic revisions.
Taisei changed their name to Tamron Co Ltd. in 1970, having trademarked the name in 1958 as a brand for their line of lenses
The Adaptall system was introduced in 1976, which again has improvements over the Adapt-a-matic system, including a bayonet mount instead of the screw-based locking ring, provisions for open-aperture coupling from the beginning, an improved mechanism for automatic stop-down, and a reduced flange focal distance (than the T-mount, I was unable to find the adapt-a-matic FFD).
In 1979 the Adaptall 2 & SP mount and series of lenses were introduced. The revised mount now has provisions for communicating the maximum aperture of the (adaptall 2) lens to the camera, but is otherwise fully compatible with Adaptall mounts & lenses, unlike previous interchangeable mount systems. The last Adaptall 2 SP lens was produced in 2006, but the line started to be discontinued in the late-80s to mid-90s. In 19
The Typo
On the aperture rings for Adaptall lenses, as well as the mount caps and some mounts, is listed a patent number. On the lenses is USA. PAT. No.3500736, whist the mounts list USA. PAT. No.3500735. This is not, as one might expect, two separate patents for different elements of the same interchangeable mount system. Instead, in 1967 Taisei files for patent US3500735, 'Adapters for automatic lens system usable with different reflex cameras', which is granted in 1970. In 1969 Tamron files for US a differnet one, same tapent. Where 736? well in 196? Kodak files for 736, coincident rangefinder. So why on Tamron lenses? Fukn Typo m8
