Bausch & Lomb Planetograph F-8 and "Three Focus" lenses?

[HalideReducer]

I have two Pony Premo 6 cameras (https://www.largeformatphotography.info/forum/showthread.php?158803-Getting-to-know-the-Pony-Premo-6(s)), one made by Rochester Optical and the other one after Kodak bought them out in 1903.

205125 205126

The older one, on the left, has a shutter labeled R. O. & C. Co on the top, and AUTO on the bottom. It has 1, 1/2, 1/5, 1/25, 1/100, B and T settings. It has f-stops marked for f8 through f128, although there's a tick to the left of the 8 so maybe it's an f6.3 lens. Amazingly the diaphragm seems to work and it fires on all settings. The lens is labeled Bausch & Lomb Opt. Co. Patent App'd. The front and rear elements both unscrew. The outside of the front brass barrel is labeled Three Focus.

The newer one, on the right, has a 3.5" square lens board. The shutter is labeled Eastman Kodak Co. Succ'rs to Rochester Optical Co. It has the same shutter speeds and aperture settings, and the diaphram and aperture blades work great. This one will fire on all settings but the shutter sticks open when set to 1s or 1/2s. Inside the front lens ring it's labeled Bausch & Lomb Optical Co 5x7 Planetograph F-8 E.F. 8 1/2 In.

Both have a 32mm outside diameter and look like a good fit for a Series 5 or 6 push-on filter adapter.

I think I need an air bulb remote shutter release but I can fire it with the lever on the side of the shutter.


Does anyone know anything about the "three focus" lens? Focal length? Is it meant to be convertible?
Any suggestions on unsticking the slower shutter speeds on the Planetograph?
Between the two lenses, any thoughts on the image characteristics between the two?

[J. Patric Dahlen]

I couldn't find information on the "Three Focus" lens, but it does indeed sound like a triple focus/convertible one, meaning that you can use the complete lens, the front or the back group. If it doesn't have three sets of aperture markings it would be tricky to use the front or back group. Have you checked how many elements it has? Since it doesn't have a tradename I suspect that it's not an expensive lens, but could be a slightly unsymmetrical four element one, perhaps a Double-Gauss.

The Planatograph should be an aplanat. The Three Focus lens could be better corrected (the complete lens). The best way to know is to compare them.

[Ron (Netherlands)]

For sure very nice shutter/lens combo's. If you look at the ground glass screen, you could compare both lenses - perhaps focal lengths are almost the same....
The newer shutter seems a rebadged B & L automatic shutter from about 1906 or 1910. Here's one disassembled (but I guess in the end the shutter was not repaired): https://www.youtube.com/watch?v=F0Ha5ViYlo8

Wollensak after he left B & L made a comparable automatic shutter:

http://piercevaubel.com/cam/imagesacc/wollensak%20auto%20shutter%2021%20jan%201902-1-small.jpg

[HalideReducer]

I just got some film holders in the mail, so I think the next step will be to set them up side by side this weekend, shoot a couple frames, measure the focal lengths, and try out combinations of front & back groups.

[Steven Tribe]

There is a well known reprint of the 1898 ROC which I own.
By 1898 they were only up to model no. 5, unfortunately! ROC was soon taken over by Eastman, but the ROC name was continued until 1907. In 1898 there no mention of the non-symmetrical RR yet, which became an important selling novelty later.
The three focal lengths will obviously be dependent of the size format of your cameras which could 4/5, 5/7, full plate or 8/10.