focal length of #4 Zeiss Kodak Anastigmat?

[Dan Fromm]

I just received a lens engraved Zeiss Kodak Anastigmat No. 4 f-6.3. It was made by B&L, may be in an incorrect barrel or need an adjustment. I'm pretty sure that it is a Ser. IIb Tessar.

I've looked up the Ser. II Tessar in the 1906 B&L catalog posted on www.cameraeccentric.com's information section. It gives the B&L #4's focal length as 5 3/8". I've used Google to search Usenet and the web. Little more info is available.

Thing is, measuring crudely I find the lens in hand's focal length is around 7 1/2". And the diaphragm opens at least a stop beyond the f/6.3 mark. At the f/6.3 mark, the diaphragm is visible from behind the lens. So at the least the aperture ring should be reset. The lens itself is perhaps 3mm longer, both cells screwed in tight, than my suspect B&L (no mention of Zeiss) 6 1/4"/6.3 Tessar. The 6 1/4" is suspect because its aperture scale goes to f/4.5, and that's where wide open is.

Does anyone know what the #4 Zeiss Kodak's focal length is?

Oh, yeah, pretty little lens and of course I'm going to try it out.

Thanks,

Dan

[Michael Roberts]

Dan, I've just acquired one of these and have the same observations about focal length and aperture. Haven't shot with it yet. How has it performed for you?
-Michael

[Dan Fromm]

Michael, since I posted my question Seth has added a 1919 B&L catalog, look around here: http://www.cameraeccentric.com/html/info/bauschcatb/bauschcatb.html

I think the lens is B&L's #5k. f = 7.0625". Mine is clearly in a barrel with the wrong aperture scale and I'm not sure the cells are spaced correctly. Even so it is very usable. Understand, I have a better 7" lens and I use it, not the ZKA #4, but if I were forced to use the ZKA #4 I wouldn't feel deprived.

I've seen many comments to the effect that uncoated lenses aren't fit to be used with color film. This isn't true of f/6.3 tessars.

Cheers,

Dan

[Jim Galli]

Dan, I had one a few eon's ago and it was in one of the little US made 1903 ish Compound shutters that had the funny angled release for air bulb hose. I rough measured with it focused at infinity and came up with 165mm. Aperture to GG with a ruler.