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northcarolinajack
10-Apr-2013, 08:54
Question on the type of Voigtlander lens I have. When I purchased I thought it was a 17 ½” F-6. When mounted and focus at infinity it seems the length is 19/20” measured from rear lens to film plane. If measured from the waterhouse stop slop it would be longer. I shot it at F-6 twice and both were overexposed by about 2 stops.
The photos attached - show #5 -- #23302 (1863) - Voigtlander & Sohn –
Wien – Braunscohneig.
Any help would great. The only catalog I have been able to find is from 1890. Plus, all the info I read in very confusing.

Jack

goamules
10-Apr-2013, 11:40
You are in the best position to answer your question, which is implied as, "what speed is this lens, I'm over exposing?" Voigtlander made a bunch of changes to all their lenses over the 19th century. And you cannot rely on their catalogs being perfectly accurate either, even if you have the exact catalog, from the exact year your lens was made. Your lens is from 1879, not 1863. In other words, a "pre Euryscop" no. 5 of 1879 can be quite different than one in 1890. Your catalog is from 11 years after this lens. But again, what is reading the catalog going to tell you? Only it's model number and what the marketers said it's speed is back in the 1800s....

Instead, I would simply measure the speed of the lens you have, on the camera. Do this; focus on your subject. Measure from the waterhouse stop to the ground glass. That is your working focal length. Now walk to the front of the camera and hold your ruler up to the front of the lens. Measure the apparent aperture, the circle of light you can see. Not just the glass diameter. Divide the working focal length by this number. If you measure 20 inches, and the circle of light looking through the front glass is 4 inches, you're at F5. Shoot accordingly.

Steven Tribe
10-Apr-2013, 12:22
It's quite amazing how many of these big pre-Euryskops ended up in the USA!
In general, the bigger sizes are somewhat slower than the catalogue series IV and approach the series VI.
A number 5 series VI would have a focal length of 24".
As Voigtländer were good enough to give the front glass diameter in their early catalogues, it would help to know yours.
But Garrett's explanation about actual aperture will give a more correct F calculation, especialy as there is a Waterhouse baffle constructing the barrel.

northcarolinajack
10-Apr-2013, 13:16
Thanks, I will do this either this pm or tomorrow. One item I failed to note, the lens has one waterhouse stop that measures 1" and marked 20. Would be surprised if the would be F-20, but who knows.

Jack

Steven Tribe
10-Apr-2013, 14:44
1" F20 (if the modern scale!) means focal length is 20". But Voigtländer had their own scale too.

Louis Pacilla
10-Apr-2013, 19:40
This may help you answer some of the questions you have. This is a pretty early catalog (1882) listing Euryscopes. That's just two or three years after yours was manufactured.

The attachment was Taken from a 1882 The Photographers Friend Catalog "Walzl Photographic Arts Emporium" Richard Walzl Baltimore Md. Awesome Catalog!:D Here's a link to the Catalog http://piercevaubel.com/cam/catalogs/1882walzl.htm

northcarolinajack
11-Apr-2013, 07:42
OK, I set the focus on the house across the street, measured from the waterhouse film plane, this is 21 1/5'. So with the 1" waterhouse, marked 20 is F21.5.
Full open is 2.5" so that sould be F8.6.
Now, could anyone tell me the type lens?

Thanks for you help. I wanted it to be a Euryscope, but how can I tell this.

JaCK

goamules
11-Apr-2013, 09:37
Glad you got it worked out. At F8, it's a Rapid Rectilinear. Their trade name later was Euryscop, but that's the same design.

northcarolinajack
11-Apr-2013, 09:59
THANKS ALL!!!

Film processed and turned out fine.

Jack

Steven Tribe
11-Apr-2013, 10:00
It is the forerunner of the series VI Eurykop and will have a coverage of around 14x17" which some will find attractive.