PDA

View Full Version : Wollensak f16 Symmetrical Wide Angle info?



goamules
24-May-2008, 16:49
Hi,
I just got a Wollensak in brass barrel that reads "Symmetrical Wide Angle" and 5x7.

I didn't find out the max aperature is f16 until I received the package. At first I thought the iris was stuck, because viewing the hole at max opening is only about half the size of the lens. But checking the tiny marks, that's as wide as it goes. It runs from f16 to f128.

I'm not finding much on this lens, though it is briefly mentioned in the 1906 catalog. It seems to disappear early in their line, I suppose replaced by the f9.5 Velostigmat WA.

Questions: Does Symmetrical mean it's a rectilinear? Has anyone used one?

Thanks for any info on this unusual lens.

seawolf66
24-May-2008, 18:21
Try this web site guaranty plenty of reading on Wollensak Lenses:

http://www.cameraeccentric.com/

Have a good holiday:

Toyon
24-May-2008, 18:45
This is the typical opening of a 19th century wide angle rectilinear lens. Some of the sharpest lenses I have ever used are of this design, though the sharpness covers only about the center 30 degrees as they are not flat field lenses. The later 9.5/12.5 Wolly wide angle lenses are not rectilinear lenses. Wollensak made excellent rectilinear lenses, so you should expect good performance.

goamules
24-May-2008, 19:15
Yep, been to that site first, only a brief description from the 1906 catalog.

Thanks Toyon, that's what I hope. Believe it or not, this is replacing the 120mm Dagor I had, and just sold on the auction site (it had no markings for aperature, and wasn't in a proper mount). I'll try it on my quarterplate stuff. I needed at least one wide lens, the petzvals sure arent!

Chauncey Walden
24-May-2008, 22:06
So how many apertures are there and how are they marked?

IanG
25-May-2008, 02:15
A maximum aperture of f16 is not unusual at all for EWA lenses. Sometimes lenses have a faster focussing aperture but most don't.

The EWA Zeiss Protar is actually an f18, but the licensed Ross version is f16. You don't say what focal length your lens is, the f16 151mm Protar design will cover 10x8 with room for movements.

Ian

goamules
25-May-2008, 07:19
Thanks for the good background info about f16 lenses.

I measure the focal length at 5.5 inches. The f-stops are marked 16 - 32 - 64 - 128 which I assume is the old US standard (f 16 - 22 - 32 - 45 today). I held it to the 4x5 groundglass and it looks good, wideangley, and it's marked 5x7 so it should cover my half plates I've been shooting fine. Any larger is bonus.

Neil Purling
25-May-2008, 07:20
The Wollensak lens will probably have a focal length of about 5 inches, which is what focal length would be appropriate for 5 x 7.
I have a 6 inch f16 W.A.R. by Wray. I have sent this and a no-name W.A.R just marked with the plate size 6 1/2 x 8 1/2 off to SK Grimes. I wanted a opinion on if the cells of the Wray could be mounted in a shutter and preserve the extraordinary coverage.

You mentioned field curvature, is this always away from the plane of focus?
This might be useful to know, when a nearer object at the edge could still be relatively sharp.

Anyone know what the best apertures might be for compromise between edge sharpness & centre definition?

Ernest Purdum
25-May-2008, 09:13
Regarding whether "symmetrical" also means rectilinear, it doesn't necessarily. It just means that the back cell is a mirror image of the front. In this instance, though, I would guess that both cells are achromatic, related to the Rapid Rectilinear, though noiw far from Rapid and with the cells very close to each other to allow for a wide angle view. There were symmetrical lenses made up of single elements front and rear and, of course, many modern lenses are close to symmetrical.

Wollensak was originally a shutter maker, but they bought out the "Rochester Lens Co." which made several variations on the Rapid Rectilinear theme. I am guessing that this is one of them.