Mounting a projection petzval in shutter

[Hollis]

I know that some of the smaller lenses can have a shutter mounted to the front but I was thinking more along the lines of taking the front and rear cells out of a projection petzval (rack and pinion style) and making a new barrel for them but in two pieces and threaded on both ends. Therefore, one end would accept the lens cells and the other end would thread into the shutter (say, a copal 3) and vice versa for the other half.

So, is this possible? I don't see why not. Probably expensive but worth it.


Hollis Bennett

[C. D. Keth]

It can certainly be done. As you expect the cost would be pretty enormous since all of the machining would have to be custom and very high quality and precise. If you want to start talking specifics, I hear skgrimes is the place to call.

[Don Dudenbostel]

I'm thinking about doing the same thing. Just picked up a very nice small petzval from one of the LF members and love the results. I have a spare copal 3 and it will work with a new mount plus give me an aperture control. Grimes seems to be the prime choice but I was wondering if there are other sources that regularly do this. I had a neighbor many years ago that was a precision machinist and optical designer and builder that made new mounts and put some lenses in shutters. He also could re cement lenses but unfortunately he's no longer living.

[cjbroadbent]

Maybe these shutters and lens grips will stimulate some ideas. They were well designed are are still trusworthy.
I mostly use the sphincter thing on the lens-board. It just grips a lens. The top one both grips and shutters. the others just shutter, and screw in front of the lens. They need a real bulb!

[Paul Fitzgerald]

Hollis,

Why not just mark and cut the barrel to fit the shutter? The Wollensak factory did retrofits that way to install Studio shutters. If the barrel was too large, they made 'stubs' to fit and silver soldered them into the barrel ends. This way is a one-way-street but it's faster, easier and cheaper, less machining.

[Pete Roody]

Why not mount a Packard shutter to the front of the lens?

[Pat Hilander]

Maybe these shutters and lens grips will stimulate some ideas. They were well designed are are still trusworthy.
I mostly use the sphincter thing on the lens-board. It just grips a lens. The top one both grips and shutters. the others just shutter, and screw in front of the lens. They need a real bulb!

That iris holder with the built-in shutter is sweet! Ive never seen one before, but it would solve a lot of my mounting/shutter woes.

[BarryS]

No kidding! Are those shutters equivalent to studio shutters? Can you set an aperture with the same blades? and more importantly--do you have any of those you want to sell?

[goamules]

Most of the projection lenses I've had that have a focus knob will come out of the assembly in a chrome tube. That might be mountable to the right sized shutter by threading, gluing, soldering etc. But inside that chrome tube is usually a outside threaded brass tube, with the lens assemblies inside that. If you got lucky, these threads might match some shutter, or again, glue, solder etc. The way I see it, you can save a lot of money by just using some ingenuity. That's what a "pro" is going to do anyway, make something work. Unless your time is more valuable than the cost....

[Ernest Purdum]

Hollis, you could save some money by choosing a less expensive shutter than a Copal 3. A large Betax, Alphax or Compound would get the job done.

I don't think mounting Petzval cells requires quite the same precision in centering and spacing as modern anastigmats. A local machinist could probably do a satisfactory job.

If you find the tubing needed, that should bring the price down. Finding it is a nuisance unless the shop happens to have some in their bin. Brass is very hard to find except for large special orders, but aluminum alloy is much easier.

I hope you can try the lens first. It would be a shame to go to the trouble and expense then find out you don't like the results.