Bausch & Lomb-Zeiss Protar lens

[sean]

Hello,
Since i am new to largeformat photography, i want to know how to operate this lens. It looks like this lens is pretty different from other lens that i have seen.

i am wondering what aperture it is when it is all the way stepped down. This lens was from my father and he mounted this lens to an ilex shutter. I dont know if he used it or not, but want to test it out. Since it is already in the ilex shutter, am i using the shutter to adjust the aperture? or the other shutter which is part of the lens itself?

[Peter K]

The Protar was the first anastigmatialy corrected lens, invented 1890 by P. Rudolph. Protars are unsymmetrical lenses with two cells. One can also use the front- or the rear-cell alone, but with two cells the aperture is in between the two cells.

This lenses where equipped with a f-stop scale with three different values, normaly the lower for use with both cells and one for the rear- and one for the front-cell alone.

Possible the second shutter was mounted because the original shutter isn't working anymore. But you have to use the diaphragm of the original shutter.

Peter K

[Ole Tjugen]

There are also very many different Protars, and only a few of them are intended to be convertible. The Protar VII is the best of these, and may be the only one made by B&L. Zeiss Jena reused the IV designation for a short-lived convertible, but I believe all B&L Protar IV's are the f:12.5 moderate wide-angle.

Without a little more information it's very difficult to give general advise on Protars, since there are som many different ones.