[LargeFormat] APO-KYVYTAR info

[Jim Hemenway]

Clive and Tim:

The following is from the beat up information sheet, (a letter) which
was packaged with my 305/537 APO-Kyvytar and in the box with the Korona.

It is not dated.

"APO-KYVYTAR lenses are made by the same people in Japan that made the
convertibles under the "Computar" trademark which I used to own and
which I sold to Chugai International Corporation who use the trademark
for their video lenses, enlarging lenses, and the large format taking
lenses (Computar Symmetrigons).

The APO-KYVYTARs are the same formula as the former Computar
convertibles except that the APO-KYVYTARs are one stop faster, i.e., 6.8
instead of 9.0. The 1/2 field angle is 38 degrees.

The APO-KYVYTARs convert to a focal length just a little less than
double the nominal focal length simply by un-screwing the front element
and using the rear element.

The APO-KYVYTARs convert in focal length as follows:

From 150mm to 264mm
     210      370
     240      422
     270      475
     305      537
     360      633
     480      845

The diaphragm scale is a double scale.  The second scale is for use with
the single rear element. The rear element alone is slightly softer and
therefore good for portraits where it is desirable to shoot farther from
the subject and soften the texture of the subjects faces.

Both elements together give you the sharpest picture, and flattest
field, and the best color that money can buy!"

It is signed by J. Callahan, President, KYVYX Corporation, South
Hackensack, NJ.


Tim Atherton wrote:

> 
> The Kowa graphic is apparently the same as the Kyvitar and Computar. There
> is also a WA version of it apparently, as there seem to be for many of these
> process lenses. But they do come in different versions as process lenses,
> some that unscrew easily and fit a shutter, other that need some work.
> 
> tim