B&L Zeiss Protar Series VII Lens

[Ari]

While waiting for the Forum to return, I tried to find out more about this lens, which I picked up locally for $150.
The internet had some general information, but I didn't see anything like this lens.

Its front element reads 16 1/2 inches, the rear says 23 1/2 inches.
There is significant balsam separation in the rear element, producing a neat circle in the center of the rear element.

The lens itself is remarkably sharp and quite easy to focus.
I have found at least 10 focal lengths by switching around the front and rear sets, and also by reversing the cemented elements.
Focal lengths range from 6,75 inches to about 29 inches, all of which cover 8x10.

My question is threefold:
1/
How do I use the aperture properly? The barrel reads f=12,5 in three areas, for different focal lengths (19, 23 & 27 in.), none of which I have found.
However, the aperture opens wider than f10.

2/
Can I do anything about the unsightly balsam separation?
I hesitate to do so, since the lens is a fantastic performer, but maybe the damage will only get worse.

3/
The thread diameter is about 75mm; is there a shutter in existence that can be used with this lens?

Pardon my ignorance, I know very little about older brass lenses.

Any advice and suggestions are greatly appreciated, thanks in advance.

[Steven Tribe]

The B&L series VII cells are well made and the multi-balsammed lens can be removed easily, separated and rebalsammed. I have done it. You can use the "lidless" brass cell as a support.

[Ari]

Thank you, Steven; through the Forum, I have just been referred to a shop that can re-cement the lens, and they're in Canada.
Though that doesn't mean I would do it, at least until I find out more about the separation and how long until the lens becomes unusable.

And from what I've been able to glean off the internet, an Ilex #5 or Alphax #5 would be able to accommodate this lens, since both shutters use a 75mm opening.

[Steven Tribe]

And they can harvest Canada Balsam in their back garden!

[goamules]

These are very nice, contrasty lenses, similar to a Dagor in that they're all cemented, no air spaces except between the groups. But they're not too expensive in this size, yet repair would be. Or if only one group is separated, just remove it, and use the good group (in the rear, behind the iris). That's how you get the different focal lengths on the scale. The rim of the lenses will give the focal length of that individual element only. Then you pull the brass sleeve off the barrel, and reverse or rotate it to get the correct F-stop range for that configuration. There is a catalog on Camera Eccentric for this lens, showing the different configurations you could buy, and coverage. Your 16" and 32" groups should be about middle of that, combined.

If they're both separated, I'd look for a better example.

[Ari]

Garrett, thank for your reply.
Yes, these are very nice lenses, giving a smooth and contrasty look, and quite versatile as well.
I did use only the front cells so far, as they are free of any separation, and I can get 13" or 16" out of them, which is great.
As for what FL I should be getting, nothing is as it should be.
With both elements in place, I get about 10"; with the front only, I get 13"; with the rear only, I ran out of bellows at 27". This is all assuming that the cells are positioned properly (convex side facing the subject?).
Any writing or indication of FL on the lens itself is long gone.

Thanks again for your help.

[desertrat]

I have a 10-1/2 inch TR triple with severe separation in the front group, leaving only a small clear aperture near the center of the group. But the separation is at the back of the group, near the iris diaphragm, so at small apertures all the light reaching the film plane passes through the small clear area. Image quality is not affected at the apertures I usually shoot at, as far as I can tell, so I haven't tried to do anything about it.

If the separation in your Protar is in a similar location, image quality might not be affected at the smaller stops.

[Ari]

Indeed, I think the separation is in the same place and identical manner as yours.
I haven't tried the rear cells yet, but I will: wide open and stopped down.
Thanks.

[IanG]

The larger front mounting Thornton Pickard shutters that would work well with this lens, or you can use the behind the lens type which fits between the lens board and the lens. They were made to be used with lenses like this in fact Ross sold TP shutters them themselves. Kodak also sold them, they are in a 1941 Professional catalogue and production only ceased in the late 1950's.

This is a small TP shutter fitted on the un-named lens of a Houghton Victo Quarter plate:

http://www.lostlabours.co.uk/photography/cameras/images/QP_shutter.jpg

This one is the between lens type fitted to a Houghton Duchess half plate camera:

http://www.lostlabours.co.uk/photography/cameras/images/hp0024.jpg


The larger sizes of these shutters aren't as common but they do turn up occasionally, the best have a speed indicator and give T, and 1/15 to 1/90. I've refurbished them for people to use with Petzvals/Darlots etc. One advantage of these shutters is a large one can be used with a variety of lens. I will be selling some in the next few months but none large enough for your lens at the moment.

Ian

[Ari]

Ian, thanks for the idea, it's a good option, though it might look odd on a Toyo 810M :)

[IanG]

Ian, thanks for the idea, it's a good option, though it might look odd on a Toyo 810M :)

You have to culture the eccentricity Ar i :D

There were Aluminium bodied TP shutters as well B&J sold them in the US


Ian

[Ari]

You have to culture the eccentricity Ar i :D

There were Aluminium bodied TP shutters as well B&J sold them in the US


Ian

Lots of options for different shutters and looks; thank you, Ian.
And from the sounds of it, I may or may not have to grow a handlebar moustache or something.

[Ari]

One more question: are these lenses (or types of lenses) known for exhibiting any focus shift?
Beyond f32 I can't see the image well enough to re-focus, and the barrel shows I can stop down to f256 (!)

Thanks.

[coisasdavida]

This is all assuming that the cells are positioned properly (convex side facing the subject?).


Isn't it screwed behind the iris for single cell usage?

[Ari]

Yes, but the cells themselves are also reversible, giving more FL options.

[Jim Galli]

The Bausch & Lomb Zeiss license protar's were sold as individual cells, or in sets of individual cells to combine for different foci. It appears yours originally included 3 cells, 19" 23 1/2" and 27". Then, the 16 1/2" cell must have been bought separately to give even more options. Along the way the 19 and the 27 have been lost and you have what you're holding, a Protar VIIa set with 16 1/2 and 23 1/2 cells. According to the catalog, those would combine together to make an 11 inch lens.

You'll see that the ring with the focal lengths can be slid off the barrel and put the notch so the length in use is next to the pointer. That only helps you on the 23, and even that not so much because it is the old US system.

The Zeiss built lenses used to give you a scale in mm which I rather like. Measure the focal length with a ruler and divide the mm into the length and bingo.

The 1912 catalog is here (http://cameraeccentric.com/html/info/bauschlomb_8.html).

Re-cementing is fairly do-able, and the lens isn't worth 4 digits of money if you booger it up.

[Ari]

Aha! Mystery (to me) partly solved.
Thank you, Jim, and I appreciate the link to the catalogue.

FWIW, this lens produces superb images, very sharp and of smooth tonality; whether it's worth $5 or $500, I think it's killer.