"Sinar" name on Symmar lens

[Bob Salomon]

As I recall from experts, neither Sinar nor Linhof actually did their own testing. They did request a specific testing regime from the manufacturer, and the manufacturer certified that the lenses met the requirements of Sinar and Linhof. There is nothing to suggest that their normal run of lenses did not also meet those requirements.

No. I have been in the factory testing facilities at Linhof and yes, they did their own testing.

Linhof, and Sinar, both purchased a Siemens Star generator from Rodenstock and used that for most of their testing. It projects a series of Sieman's stars onto a large wall. The tester can rotate the lens in the projector by remote control and see problems that show up as the field rotates. The wall that they are projecting on is several feet high and wide.
In another room technicians are examining assembled and finished lenses for imperfections, dirt, smudges, dust, etc. within the optical system. Find any and, if it can't be easily cleaned out the lens is returned. Another technician tests shutter speeds.

All lenses tested by Linhof, from Rodenstock, Schneider or the few from Nikon that they used, had passed all of the manufacturer's tests. If Linhof rejected a lens it was still a lens that met all of the lens manufacturer's requirements.

For some special application Linhof cameras, like a Technorama 612 or 617 system, a tested lens might have defects outside the live image area that the camera used but the lens was a perfectly good lens within the application field of the camera. Lenses that performed particularly well in the live image area of these cameras were set aside for use only on these cameras. Since these lenses had helical focus mounts and special lens cones and len boards they were not usable as a view camera lens.

Linhof also had specially corrected lenses for their aerial cameras which were designed specifically for use at legal minimum aerial altitudes or above. The highest altitudes these off the shelf Linhof aerial lenses were used at were in the Space Shuttle during flights.

There were also other procedures used by Linhof over the years. Before they used this system they had a wall sized chart like the USAF test chart that they inspected lenses on optically.

I have not visited the factory since the current owner bought it but have had no indication or reason to believe that they no longer perform their own tests. They just would not be doing it in the volumes that they did in the past thanks to market conditions.

[Arne Croell]

I don't know about Sinar, but I have seen the actual Linhof testing Bob describes during a factory tour as part of a workshop in the early 1990's - they certainly did it then. They also demonstrated certain lens aberrations at the time for us using the Siemens star projector and certain lenses.