Extension Back or Lens Cone for Canham 5x7?

[Don Dudenbostel]

I have a 600mm Fujinon C that I purchased to use on my 8x10 but would also like to use it on my Canham 5x7 traditional wood body. The Canham has just enough bellows to focus down to about a 150ft but i would like to work a little closer. My Canham uses the traditional 110mm Canham lens board and I don't want to convert it to a Technika front standard. I also have the Technika adapter but don't really like the way it works. Is there a 110mm extended cone type lens board that might extend the lens another two or three inches? I noticed that Ebony makes an extended back for theirs. Basically the back is a box that snaps in the place of the original back and the original back snaps on the back of the box giving another four inches of length. Anything like an extended back for the Canham?

Thanks!

[Jason Greenberg Motamedi]

I don't think there is anything made commercially (by either Keith Canham or Toyo), but I am sure you could have something made by a machine shop or woodworker. Have you called Keith? He is always full of ideas.

I have a small 2 1/2" extension/top-hat made by Grimes many years ago on a Canham board which I have used for long lenses. The front standard can't carry much weight when it is poking out like that, but a small lens like the Fujinon-C should be fine.

I think, but am not positive, that the Toyo recessed boards will work as extension boards, just flip them over. However they won't give you very much extension, only 1" at most.

[Don Dudenbostel]

I thought I would see if anyone knew of a solution before calling Grimes or Canham.

2-1/2 inches would be great. Do you remember the cost?

[Jason Greenberg Motamedi]

All in all, it ran about $225, but that was quite a few years back, when Mr. Grimes was alive and prices were lower. The project started as a stand-off lensboard so I could use a 12" Heliar in a Compound no. 5 on my 5x7. I later had a Grimes make a screw-on cap for the stand-off with a hole for a Copal 3, and thus a top-hat was born...

[Gem Singer]

The Fuji 600C is mounted in a Copal 3 shutter. Kind of heavy to hang way out there with the bellows fully extended on the Canham 4X5/5X7 camera.

Even if you used an extension lens board, It would be difficult and expensive find one that will take a Copal 3 shutter. Rear extensions would not be possible without fabricating an entirely new back for the camera. Canhams do not have international backs.

A 600mm non-telephoto lens is beyond the capability of the Canham. A Nikkor telephoto would probably be more suitable.

[Jay Wolfe]

Check listings for an Ebay seller "jinfinance" and/or contact him directly. I have a Technika-type top hat from him that is very nice. If the Canham/Toyo type is not listed, he may be able to get it. Probably at about half the cost of a custom made fixture.

[Don Dudenbostel]

I have a Technika top hat that I tried with the Technika to Canham adapter. It is a heavy package sticking way out there for sure. I don't really like using that combination and really dislike the adapter all though it works. My thought was that an extension box would work better. I really don't think it would be a difficult arrangement for someone that's a good wood worker to build so that leaves me out.

I have a Nikkor T set 360/500/720 but it just covers 5x7 and don't want to spring a bundle on another 600/800.

[John Schneider]

How about using recessed board from an enlarger and reversing it and mounting it to a Canham board? Durst and Omega come to mind as offering deep recessed baords that might work for your application.