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Steve Sherman
10-Jan-2005, 05:02
I have a Wollensak Extreme Wide Angle 159mm lens F12.5. I seem to remember that you can remove one screw which would allow the aperature to open up to F 9. Can anyone describe for me how to accomplish this. Thanks, Steve

Scott Soper
10-Jan-2005, 08:36
I no longer have my Wollensak E.W.A., but I recall it was a fairly simple operation.

However, at the new widest aperture, the image will be too soft for critical focussing. You CAN get a moderate improvement in brightness by opening up just a little, and still be able to compose and focus. That's probably around f9, and would be a useful modification.

I recall you can open up wider than that: you just won't find it useful for focussing.

At least, that's how my particular Wollensak was.

Mark Sawyer
10-Jan-2005, 09:35
Which brings up a question I've wondered about; are the Wollensak 159mm f/12.5 and 9.5 actually the same lenses, but one opens wider for focusing?

tim atherton
10-Jan-2005, 12:28
I think it depends in part what version and what shutter it's in as to whtere this is possible (or at least easy).

Is it in a Rapax or an Alpax (or something else)

Also - I'm fairly sure the 12.5 and 9.5 aren't the same lens - but there are also several dfferent versions of the 12.5 (whch I know soemwhat better of the two)

Steve Sherman
10-Jan-2005, 14:13
Before I purchased the lens I researched whether the two were the same. From the information on the web with respect to image circle the slower lens had the bigger coverage. I have a coated version and beleive somewhere I saw that you could remove one small screw and gain some added brightness for composing on the ground glass.

Thanks, Steve

tim atherton
10-Jan-2005, 14:44
Steve,

Yes - I've posted that on here as have others

You still don't mentiuon what shutter?

If you have a Rapax shutter, in most cases on the back of the shutter there is simply a small grub screw that acts as a limiter to the aperture lever. Simply unscrew it and remove.

I'm not sure if you can do the same with the Alpax shutters (or Betax).

As mentioned - with the 12.5 limiter in place you can see there is a large part of the aperture that is then mechanically vignetted at 12.5

Without it, the aperture must open up to about 5.6 or something - but it has been suggested you may get focus shift if you focus with it that far open and/or, as above, the image becomes too soft for accurate focussing. I generally open it up to what would be about f9 just to get a bit more light but avoid those problems.

My guess is that at f9 it is unacceptable for actual image making, but fine for focus and that Wollensak limited it to 12.5 so people wouldn't be tempted to actually photograph at f9

And yes, my understanding is that the 12.5 has the larger image circle than the f9

Steve Sherman
10-Jan-2005, 14:53
Thanks Tim,

Alphax shutter with three small screws which appear to secure the outside plate to the back of the shutter.

If I weren't so forgetfull I would have asked Grimes to take care of it as they had the shutter apart for a C&A.

Ernest Purdum
10-Jan-2005, 16:38
Mark, the two lenses, despite looking much the same, are quite different internally. The faster type has eight elements in four groups instead of four in four..



Wollensak said that the reason behind the more elaborate lens was not to gain greater coverage, but just the larger stop.

Mark Sawyer
10-Jan-2005, 19:45
Thanks muchly, Tim and Ernest! Any opinions which is the better lens? I'm quite happy with my uncoated f/12.5 in a Pi-Alphax shutter; it's given me some lovely (at least to me) images. But in weaker moments I've considered a coated one. Are the EWA Velostigmat and Radar 159mm's just early versions of the same lens? Sorry for all the questions, but this is perhaps my favorite lens...

David G. Gagnon
10-Jan-2005, 20:46
Steve,

I asked the same question about a year and a half ago on photo.net. Here's the link if you're interested......


http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=005ULH (http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=005ULH)

As I recall, the front element screwed out of the shutter and the screw was right there for easy removal. You'll probably want to save the screw in a safe place if you ever want to replace it. I did not notice any focus shift with mine by focusing wide open and stopping down for exposure.

DG

Ernest Purdum
11-Jan-2005, 20:08
Mark, I'd never suggest anyone get rid of a lens he particularly likes, but it is possible that you'd like the same lens coated even more.



As to which is better, a (not very) larger aperture is desirable, so I suppose the faster one would be considered the better, but since you like the 12.5, I wouldn't worry about it.



The Velostigmat is the same except for being older. The Radar is a competitor made by Gundlach.

Mark Sawyer
11-Jan-2005, 22:15
I wouldn't get rid of her, Ernest, I'd just get her a playmate. I figured coated for cold weather, uncoated for when it gets hot.

And I don't worry too much about the maximum aperture for focusing, as my eyes are getting so bad I can hardly focus anyways. I only use an 8x10 camera because those little 4x5's are so hard to find around the house. If my eyesight gets any worse, I may have to go ULF...