Is it possible to make your own Waterhouse stops?

[ame01999]

I see some sets available on eBay, but I imagine these things were custom made to fit a specific lens, right?

With laser-cutting capabilities, it seems feasible to design one's own Waterhouse apertures. Diameter could be calculated as focal length/ aperture. But if I don't possess a single Waterhouse stop to use as a model, how would I determine the length of the insert? It would have to correctly place the aperture exactly in the center of the lens, right? Thanks for your advice.

 

[Dustin McAmera]

Of course it's possible. Early photographers made their own stops without laser cutters. You need some sheet brass, a fine saw, one or two files and a drill.

If you can get the front group of lenses off to see inside the lens barrel, that would be the easiest way to measure the shape the business end of the stop needs to be.

If you can't do that, you can use a narrow strip of metal or card as a probe, poking it into the slot to see how far it can go. Put a straight edge across the lens barrel so it makes a tangent to the curved surface of the lens barrel at the middle of the slot. Measure how deep the probe goes, at the middle of the slot (deepest), at each edge, and maybe a couple of intermediate points. Mark where the probe crosses the straight edge, then pull the probe out and measure the depth.

These depths give you the shape of the stop. It's probably a circular curve. Cut a metal strip the width of the slot; allow some length for the handle part; then mark the depths at each point across the width; that lets you mark the curve of the business end. File the end of the strip to that curve. The hole needs to be drilled at the centre of that circular curve. If you want to be fancy, you can use a dremel or something to sand the edge of the hole to a fairly sharp edge.


You could do it with black card to avoid working with metal.


Strictly, relative aperture is calculated from the diameter of the entrance pupil, not that of the actual hole. That's sort of the diameter of the actual hole as magnified by the front group of lenses. So calculating it from the actual hole will make your f-numbers slightly too big; but for a first go I wouldn't worry about that.

 

[Arthurwg]

SK Grimes used to make them to order. Don't know if they still do.

 

[Dustin McAmera]

Says so:

Waterhouse Stop

Portrait and early landscape lenses were often made without adjustable iris. Instead, there is a slot intended for the insertion of interchangeable metal or cardboard plates, each with its own fixed

skgrimes.com

 

[ame01999]

Of course it's possible. Early photographers made their own stops without laser cutters. You need some sheet brass, a fine saw, one or two files and a drill.

If you can get the front group of lenses off to see inside the lens barrel, that would be the easiest way to measure the shape the business end of the stop needs to be.

If you can't do that, you can use a narrow strip of metal or card as a probe, poking it into the slot to see how far it can go. Put a straight edge across the lens barrel so it makes a tangent to the curved surface of the lens barrel at the middle of the slot. Measure how deep the probe goes, at the middle of the slot (deepest), at each edge, and maybe a couple of intermediate points. Mark where the probe crosses the straight edge, then pull the probe out and measure the depth.

These depths give you the shape of the stop. It's probably a circular curve. Cut a metal strip the width of the slot; allow some length for the handle part; then mark the depths at each point across the width; that lets you mark the curve of the business end. File the end of the strip to that curve. The hole needs to be drilled at the centre of that circular curve. If you want to be fancy, you can use a dremel or something to sand the edge of the hole to a fairly sharp edge.


You could do it with black card to avoid working with metal.


Strictly, relative aperture is calculated from the diameter of the entrance pupil, not that of the actual hole. That's sort of the diameter of the actual hole as magnified by the front group of lenses. So calculating it from the actual hole will make your f-numbers slightly too big; but for a first go I wouldn't worry about that.

Thank you, Dustin and Arthur. Is it true machinists like Grimes can also slice a slot in the middle of an intact antique Petzval barrel lens? That sounds to me like brain surgery, but I have no experience in these matters!

 

[DREW WILEY]

Brass shim stock could simply be punched. Drilling metal sufficiently thin risks burs unless it's tightly sandwiched between boards when doing so.

 

[Sirius Glass]

I believe S. K. Grimes skgrimes.com will make waterhouse stops for lenses. I have used that company several times to make one of a kind parts for large format lenses 4"x5"] and I was very satisfied every time.