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View Full Version : Tessar IIB convertible to Soft Focus


goamules
27-Aug-2008, 10:34
I don't know if many folks do this, but I took the front off my B&L Zeiss Tessar IIb and found the GG image really amazing. The multiple aperature settings suggest they considered these convertible at some point. There is a softness flair depending on aperature, and some strange effects around the edges. Anyone done much with half a Tessar?

I guess the question is, what's the difference between "needs to be stopped down for sharpness" and "soft focus?"

Thanks,

Garrett
Jim Galli
27-Aug-2008, 16:28
Tessar's are non-convertible. Yes, the rear group will focus and form an image but it's normally about 1/3 of 1/4 the focal length of the total lens system. Interesting perhaps but Mark Sawyers 1F99 magnifying glass lenses are probably more practical. What was the original length of the tessar, and what is it as a single rear group?
Ernest Purdum
27-Aug-2008, 16:50
I guess the question is, what's the difference between "needs to be stopped down for sharpness" and "soft focus?"

It all depends on the result you are looking for. One photographer's dreamy ethereal vision is another's fuzzy picture.
goamules
27-Aug-2008, 17:03
I'm measuring 8 inch complete, 5 inch just the back. What led me to think I should try taking it apart is the scales on the brass barrel. There is one f6.3 - f45 (the lens doesn't give an fstop, but I think they're f6.3 aren't they?) scale, another f3 [sic] - f256. Wait a minute, what's going on here? F3? Perhaps this isn't the correct barrel, but it sure fits nice and is about mint, like the lens.
Dan Fromm
28-Aug-2008, 03:08
Um, FWIW I have a couple of B&L IIb Tessars in barrel and both seem to be in the wrong barrel. One is in a barrel with aperture scale starting at f/4.5; that corresponds to "wide open." The other is in a barrel with aperture scale starting at f/6.3; this seems to be a true f/8.

Since both lenses shoot fairly well I think the cell spacing is more or less correct.

Yes, Tessar IIbs are f/6.3 lenses.

Anyway, if I were you I wouldn't take the engravings on the barrels seriously. Mine are, um, silly.