"SEEBOLD INVISIBLE CAMERA CORP." f6.3 5x7 Lens: Questions

**leighmarrin** · 20-Jun-2010, 02:46

While I've done some "Googling" on it, I still have some questions on a lens marked "SEEBOLD INVISIBLE CAMERA CORP. SPECIAL ANAST. F6.3 5x7" in a No. 3 Betax shutter. It came attached to a very visible and musty Korona Series IV 5x7 field camera.

Evidently John Seebold acquired the Gundlach-Manhattan company in 1928 and sold it a few years later. Any clues on the "Invisible" in Seebold's choice of names? Wonder if he made a small spy camera or felt corporately invisible as a small company amongst all the neighboring large photographic companies in Rochester?

Trying to find a similar Gundlach lens, I tried to view the Gundlach catalogs on Camera Eccentric's excellent site, but my elderly computer would only view the first few pages. Through Google I did find a reference to a Gundlach "Special Anastigmat" intended for "hand cameras", so this is probably the same lens relabeled, right? Wonder if someone with a better computer could look at Camera Eccentric's Gundlach catalog for a lens similar to mine?

It appears to be a four element air-spaced formula--I don't think it's a Tessar, but I'm not good at "reading" lenses. Anyone know the formula? (Dialyte?) While it's supposed to cover 5x7 the focal length is not stated, and I've not attempted to measure it. (Perhaps around 8"?)

There's some problems with the aperture scale, or so I thought at first. The scale goes to f45, but the aperture lever stops right next to the cable release block. Also, the level travels way past the opposite f6.3 setting. But looking closer through the lens, the f6.3 marking seems to be correct to the iris, and the lever does not quite touch the cable release block at the opposite end of its travel. So it appears that the invisible QC guys at Seebold put a somewhat incorrect aperture scale; the scale goes to f45, but the actual iris stops at about f25. Any opinions?

The Betax No. 3 shutter works perfectly on B, T and 1/50th. 1/25th is erratic and the slower speeds alternate between sticking or are way too fast. I considered attempting a lighter fluid flush before a commercial CLA, but a few Google references stated that the Betax shutter blades are synthetic and would melt. (Correct?) Another reference claimed the Betax iris is paper, but mine is looks like a dark-bronze metal.

All comments, information and opinions are welcome.

--Leigh.

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**Steven Tribe** · 20-Jun-2010, 03:00

I always assumed that they were involved in "detective" plate cameras - but it appears that they were the first generation of security camera makers. Invisable to the thief/thieves.

**leighmarrin** · 20-Jun-2010, 05:30

Steven, thanks for the info that I could not find on Google. Wonder if they used still or cine cameras for their security camera?

Ooops! The fifth paragraph of my first posting is confusing. The added sentence in ALL CAPS is what I meant to say.

"There's some problems with the aperture scale, or so I thought at first. The scale goes to f45, but the aperture lever stops right next to the cable release block A LITTLE PAST THE F22 MARK . Also, the level travels way past the opposite f6.3 setting. But looking closer through the lens, the f6.3 marking seems to be correct to the iris, and the lever does not quite touch the cable release block at the opposite end of its travel. So it appears that the invisible QC guys at Seebold put on a somewhat incorrect aperture scale; the scale goes to f45, but the actual iris stops at about f25."