Weird Coverage with Wollensak 159mm Velostigmat ?

[Scott Davis]

I've got mine (well, the f12.5 version) in an Alphax. No calipers to measure the spacing, but in that shutter, I've got sharp coverage on 8x10 or 5x12. If I apply any significant movements with it on 5x12, I do get perceptible loss of sharpness in the corners, but they remain illuminated within the range of rise/fall that my camera allows. It's one of my favorite lenses for large format. I'm pretty sure you've got a lens that's either mis-aligned or mis-configured internally for it to be that far out of whack.

[Cor]

First of all; thanks for your input its really nice to get all this feedback from the friendly people of LFPF! It is not that this lens is so valuable or something, and I can (and probably will) return it, but I would like to know/learn why this problem is occurring.

Probably I should re-phrase my problem. It is not so much that the lens does not cover, it does, it illuminates the whole 8*10 ground glass. But it is only sharp in a 5cm or so wide circle.

As if as Charley wrote: "I was just wondered about cell spacing, as too much distance might make it look like you're shooting through a tunnel."

So we all agree that the lens should cover 8*10 and stopping down did not help to improve or widen the sharp area..

My lens looks exactly the same as the one posted by Brian (thanks Brian, creative mounting btw.. so the Betax No3 shutter is correct than.

Jan has measured his lens, and my lens seems to have exactly the same spacing (although there is some room for error in measurement).

Leaves me only the suggestions by Charley (thanks for the picture of the lens elements!) and Scott..some kind of misalignment. I looked at the 2 elements, they unscrew in 2 groups ) (is that the right way to call it like that), but I did not remove the glass from their housings. I seem to recall the inner surfaces (pointing towards the shutter were convex not concave as shown in the diagram..but I might be wrong, I'll check it tonight.

Best,

Cor

[Vaughn]

I have a Wollie 8x10 Series III EX.WA f12.5 6.25" Focus in a Alphax shutter (marked "Wollensak Rochester").

On 8x10, it is significantly dark and unsharp in all corners at f45. It should not be, so I assume that I got a dog -- one that perhaps bounced back and forth on eBay a bit..who knows... I guess I could unload it on someone for what I paid for it, but that would not be a nice thing to do.

The only saving grace is that I now have a 5x7 and it will make a great lens for that camera. And I have made some nice images with it on 8x10 on those very rare occasions that do not requite sharpness in the corners (some portraits of my boys in the landscape).

[E. von Hoegh]

Cor,
Your lens might be assembled incorrectly. I had the identical lens and shutter; it covered 8 x 10 with some movement possible at smaller stops. Also very sharp - my only issue was the lack of coating.



Good luck.

[Brian C. Miller]

creative mounting btw..

You can tell that it's a quality job because there aren't any wrinkles in the duct tape.

(I need to get some more lens boards, is all. Three lenses are sharing that one.)

[Cor]

Mystery solved !

So last night I could check this lens again, and guess what: some genius had flipped around the 2 inner groups of both elements around! Thanks to the diagram Chauncey had kindly provided I knew that both inner surfaces should be concave, and they were installed convex!

So I flipped them around and now I have a sharp image over the whole 8*10 ground glass (the light was still dim at f9.5 it wasn't crystal clear, but it looked fine)!

Have to shoot some film at f22-f32 to really be certain..

The seller had never used the lens nor taken out the elements, still this exercise was a bit of a nuisance, so I hope my images will turn out fine.

Since this lens is uncoated how much of a problem is flare if you use a compendium, and have the sun in your back (shooting only B&W) ?

Best,

Cor

[Louis Pacilla]

Hi Cor

I figured it would cover. Glad you found the problem & worked it out. Great little lens that should produce fine results as long as you don't plan to do mural size printing.Contact prints will /should be fantastic.

You'll be fine as far as flare goes. Do use your shade & watch for strong direct light making it's way in.

[Cor]

Thanks Louis,

I'll only contact print, do not have a 8*10 enlarger (though access too through friendly dutch LF photographers..)

BTW I now understand why I was puzzled by the grey rim I saw (the pictures I posted do not show it very well). The flipped groups are painted grey on the back side, and when installed wrong as I got the lens the grey coating was facing towards the front of the lens.

Best,

Cor

[Balazs Szabo]

Hello there, could anyone provide some info on getting one of these in Europe? 😅

[Neal Chaves]

I have a 12.5 in Rapax, dated to 1948. Seems to have good coverage when stopped down. Haven't had much of a chance to use it, but I will because it is so small that I can always have it with me.