Odd Waterhouse Stop...

[Mark Sawyer]

I ran across a photo showing a rather odd Waterhouse Stop, seen here at the upper left. Anyone know what it might be for?

[taulen]

http://collodion.com/forum_posts.asp?TID=9702&title=please-enlighten-me-on-this
There is the same image and same question.
Its for softening image, imagon lenses (?) have a smiliar disc infront of the lens if I remember correctly

Edit:
here you can see the imagon discs :
https://www.google.no/search?hl=en&safe=off&client=opera&hs=3aQ&channel=suggest&q=imagon+lens+disc&bav=on.2,or.r_cp.r_qf.&bvm=bv.44770516,d.bGE&biw=1680&bih=966&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi&ei=Zx1hUZPAD6v74QTly4H4BQ

[Mark Sawyer]

I have several Imagons with the discs, and am familiar with the Verito stops, but I think this is something completely different. The Imagon/Verito stops have most of their aperture at the center of the lens for sharpness, with a few smaller holes/spikes at the outside areas to let in a little of the aberrations. The Waterhouse shown here would render no sharply defined image, only aberrations from the outer areas of the lens.

[taulen]

Yeah, sorry, I didnt see it was you, Mark. You might/probably be right. I was just relaying the info posted on the collodion forum since I recognized the image. Hope you find out what it have been used for. Have you tried replicating it, and see how the groundglas infact turn out ?

[Mark Sawyer]

Actually, the Imagon/Verito thing was the first thing that crossed my mind too, but it went away pretty quick as I thought about it...

No, I haven't tried replicating it. Just ran across it tonight. As most of the old Waterhouse sets are for Petzvals, the area of the lens these allow light through are well into the curved field, so it might have something to do with that, but I can't imagine shooting images though it. But I might have to make one and try... :confused:

[Leszek Vogt]

Almost looks like a slide from my Spectra meter ???

Les

[IanG]

The seller says they are made by Nebro, which was Neville Brown, not a lens maker, rather a 1950's distributor &manufacturer of miscellaneous photographic accessories including developing tanks. They'd expanded and were distributors for Aldis, Graflex cameras etc by 1961 and became part of Johnsons who themselves had been distributors of Nebro developing tanks etc.

So maybe not such old Waterhouse stops if they really are made by Nebro,unless it's just the case.

Ian

[Mark Sawyer]

Well, there were odd-shapes (squares and such) of Waterhouse Stops made for modern process lenses, but they'd still be single-hole and centered. These look like 19th century conventional Waterhouse Stops marked for various apertures, except for that one. My guess is that it's just a mis-matched case they sort of fit. But I'm just speculating, can't say for sure...

[taulen]

I just made a proof-of-concept. And it really did project a softer image, but no problem "focusing" it. So yeah, in my mind its a stop for softening the image projected by the lens, for an enlarger or camera.

[Tracy Storer]

Yeah, it should work, kind of like a "center zone blocked" Zone Plate........

[Jac@stafford.net]

What is not shown is the universal center aperture - basically a portable hole. It is usually missing due to some legendary peeping Tom.

Known in its time as a Photon Sieve. Photons were much bigger back then as evinced by the huge lenses of the era. You could sometimes hear them tumbling through the brass lens. Some were tuned like an organ pipe for a pleasant effect.

[IanG]

It would be entirely reasonable to find old stock Aldis (or perhaps Wray) waterhouse stops being sold by Neville Brown under the Nebro brand as they distributed Aldis products after WWII until Aldis were bought By Rank. Neville Brown also distributed Wray products for a time.

Finding Waterhouse stops at reasonable prices that actually fit isn't easy, I guess it's easier to make your own.

Ian