View Full Version : "Tophat" Lensboards: a question or two, maybe 3

Daniel Stone
22-May-2011, 23:10
hey guys,

I'm gonna bite the bullet and see how this goes. I just got a 47 1/2" RDA in a package of lenses. I've thought about building an 8x10 "box" camera for a while now, and I thought this might be a grand summer project now that I have the lens for it. However, I've never been all that accurate with the "Jim Galli shutter" or "lenscap method", usually futzing things up and jarring the camera by hitting the lens. So, I'm looking at Sinar DB shutters, or a packard shutter(4" opening) as the other alternative to mount to the front/back of this monster lens. This would also be preferred(the Sinar DB that is) because I love shooting color film, and chromes in particular.

So... due to the 1" or so of lens that sticks past the end of the flange in the back, I'll be needing a "tophat" lensboard to extend it out a bit from the shutter blades(w/ the Sinar DB shutter).

Any ideas of if they're available straight from Sinar? Or would it be more of a homebrew item? I have a friend who can weld aluminum, so I might be able to talk him into helping me out in exchange for a 6-pack(or a 12er if its more work ;)). I can't see it being THAT hard, just take a standard Sinar lensboard, mill out an opening(or bore one on the lathe), and weld in the tube/box assembly with the proper amount of clearance room. This way the shutter could be used with other barrel lenses possibly for other cameras/projects,etc...

Any ideas would be greatly appreciated. The lens is approx 8lbs +, so its no lightweight. Good ol brass barrel and all :). So a strong solution would be needed.



Struan Gray
22-May-2011, 23:38
I would put the lens on a normal lensboard and move the shutter. That way you don't add to the already quite large torque trying to pull the front standard forwards and down.

You can put the shutter on an intermediate standard. You are probably going to need at least one extra bellows and standard anyway, and with this long a focal length if you're using 4x5 you won't need to get the shutter right up behind the lens (which you *do* need to do with shorter lenses to avoid vignetting).

You could also make an extension piece to move the shutter back a couple of inches or so. If you have a spare format frame the extension can be as simple as a couple of lensboards with large holes and a tube linking them. You still have to make something, but it doesn't need to be nearly as strong (or aligned) as a lensboard.