Topcon T

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The Topcon T[1] is essentially a stripped down version of the Topcon RE Super. It is forms a component of the KS-20900 L1 message register camera.[2][3] made to order by Tokyo Kogaku for the U.S. telephone company Bell / AT&T.[4] The camera was designed to record telephone usage in the exchanges for billing purposes.[5]

The Topcon T, introduced in 1971, lacks the shutter speed dial,[6], the self timer, the decorative silver plate on which the shutter button and the self-timer are mounted, the (removable) finder unlock button and the exposure indicator window. The latter two are faired over with a plain metal plate underneath the top plate. The area where the detachaeable viewfinder of the Topcon RS / RE was mounted, has been replaced by a plain metal lid that is firmly screwed down. On the camera bottom, the battery control switch[7] as well as the back cover lock have been omitted and replaced by a plain metal plate underneath and a blind cap respectively. The unlock button for the camera back is now a sliding button on the left side of the body. Both the surround of the shutter release button on the camera front and the rewind button on the bottom are made of black plastic, like that of the late (black) versions of the Topcon RE Super.

The Exacta lens mount of the Topcon T is surrounded by a (male) thread of 69.9 mm diameter, onto which a 46 mm deep metal housing can be screwed that prevents the lens settings from being altered. The Topcon T was delivered with a RE Auto Topcor 25mm f/3.5 ultra-wide-angle lens, fitted with a gelatin polarising filter. The focus of the lens and aperture are locked down by the manufacturer;[2] the lens is set to 1.5m focal distance and f/22, irrespective of what it actually says. The shutter speed is fixed to 1/60th sec. The KS-20900 L12 camera was designed to photograph a bank of 100 registers with a single exposure.

The Topcon T appears to have been produced in very small numbers in 1971. For four examples we have serial numbers, all in the 71T0xxx range; three with a standard mount,[8] and one where an additional mount (for a microscope?) has been glued on.[9]



Notes

  1. T for Telephone.
  2. 2.0 2.1 Photographing Message Registers Using KS-20900 L1 Message Register Camera. Bell System Practices AT&TCo Standard Section 030-304-301 Issue 1, October 1972 (PDF of the manual).
  3. The early versions of the KS-20900 L12 were standard TOPCON RE Super units with penta-prism veiewfinders as shown in the manual. The full camera (L1) was comprised of the viewing hood (L10), the electronic flash (L11), the Topcon body (L12), and the wide-angle lens (L14), all of which was housed in a case (L15). The hood, which has two grip handles, is approximately 42 cm wide,33cm high and 53cm deep (16.5 x 13 x 21 inches).—See also: Photographing Message Registers Using KS-20900 L1 Message Register Camera. Bell System Practices AT&TCo Standard Addendum 030-304-301. Issue 1, March 1978 (PDF of the addendum to the manual).
  4. Later supplied by Charles Beseler Company, East Orange, New Jersey.
  5. トプコンT(ポスト・トプコン)TOPCON T Topcon T telephone frequency recording camera.
  6. It is replaced by a plain screw-on cap, revealing part of the mechanism below.
  7. The type with the horizontally sliding switch as used the second version of the Topcon RE Super.
  8. s/n 71T0048 (Internal s/n WE00645) with RE Auto Topcor 25mm s/n 9366817 (Photographica Collection Dirk HR Spennemann).
       s/n 71T0209 (Internal s/n ?? 08507) with RE Auto Topcor 25mm s/n 9366557 (pers. comm Kunihiro Wakita; トプコンT(ポスト・トプコン)TOPCON T Topcon T telephone frequency recording camera).
       s/n 71T0265 (Internal s/n ?) with RE Auto Topcor 25mm s/n 9366697 (eBay March 2013).
  9. s/n 71T0303 (Internal s/n ?) no lens (Pacific Rim Camera).