Home Made Waterhouse Stop

MikeK · May 10, 2005

I have an old Wollensak Portrait lens that had the iris removed. I love the results but wide open @f5.0 is a challenge exposure wise. So I was thinking about making a home made stop. The lens unscrews and so I could insert the stop between the front and rear elemenst.

So has anyone made a stop before and I am thinking that a stop that would give me f8.0 or f11 would maintain the soft effect. The outside diameter of the brass washer I would need to use would be approximately 2.5 inches. Any idea on how to calculate the diameter of the holes would need to drill to give those f-stops?

Mike

Jon Shiu · May 10, 2005

How about using a neutral density filter?

wfwhitaker · May 10, 2005

MikeK said:
...I am thinking that a stop that would give me f8.0 or f11 would maintain the soft effect. The outside diameter of the brass washer I would need to use would be approximately 2.5 inches. Any idea on how to calculate the diameter of the holes would need to drill to give those f-stops?

Mike

Mike,

You can simply divide the nominal focal length by the f/ number you wish to use to arrive at a diameter for the clear aperture. For example, a 12-inch lens stopped to f/8 would have a clear aperture of 1.5 inches. The stop should be placed at the same position as the original iris. A slot cut in the barrel of the lens would allow you to drop in stops of your choice and change them as necessary. This, at least, is how it was done with lenses which originally used Waterhouse stops.

However, let me add that Jon's suggestion of using neutral density filters is the most practical and depending upon exactly which Wollensak portrait lens you have, stopping down to f/8 or f/11 may considerably diminish the soft focus effect. The Verito by my own experience is most effective wide open and has lost much of its soft focus quality by f/8. At f/11 it's becoming respectably sharp.

You may find a combination of using homemade stops and neutral density filters to give you the optimum amount of control for your particular situation.

MikeK · May 11, 2005

Jon Shiu said:
How about using a neutral density filter?

Duh, way too simple. This is one of my problems; always jumping to the complicated solution rather than the obviously simple one.

An assortment of ND gels attached to the rear and I am in business. Now if I can make make a bracket that attaches to the rear of the lens board to mount my Cokin Filter Holder I can use my Cokin gel mounts....here I go again maybe just some simple gels and some scotch tape

Thanks

Mike

MikeK · May 11, 2005

wfwhitaker said:
Mike,

You can simply divide the nominal focal length by the f/ number you wish to use to arrive at a diameter for the clear aperture. For example, a 12-inch lens stopped to f/8 would have a clear aperture of 1.5 inches. The stop should be placed at the same position as the original iris. A slot cut in the barrel of the lens would allow you to drop in stops of your choice and change them as necessary. This, at least, is how it was done with lenses which originally used Waterhouse stops.

However, let me add that Jon's suggestion of using neutral density filters is the most practical and depending upon exactly which Wollensak portrait lens you have, stopping down to f/8 or f/11 may considerably diminish the soft focus effect. The Verito by my own experience is most effective wide open and has lost much of its soft focus quality by f/8. At f/11 it's becoming respectably sharp.

You may find a combination of using homemade stops and neutral density filters to give you the optimum amount of control for your particular situation.

The lens is a Wollensak f5 Series Approximately 12" focal length. I think the ND route willl be best

Mike

David A. Goldfarb · May 11, 2005

I'd make a stop or two as well, just so you can vary the effect. Personally, I like the Verito usually around f:6, and even though it sharpens up by f:8, the lens still has a distinctive look (i.e., not like a modern lens) stopped down past that.

Jon Shiu · May 11, 2005

I think Calumet has a filter holder that uses magnets. It probably wouldn't be too difficult to make your own out of those flexible magnet strips.

Jon

JG Motamedi · May 11, 2005

I am pretty sure that your lens was the precursor to the Wolly Vesta. If so, it is a petzval and not a soft focus lens like the Verito. Check to see if the front element is a cemented doublet and the rear is an air-spaced doublet. If this is the case I would recommend using a combination of waterhouse stops and ND filters. Petzvals, in my experience, do best around f/8 or so, retaining the swirly bokeh with a very sharp center.

I have made very simple waterhouse stops with matt-black cardboard, which work fine.

Home Made Waterhouse Stop

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