Adapting an 8"x10" Korona view camera for 11"x14" wet plate

When medium format isn't big enough: 4x5, 5x7, 9x12, 8x10 and even larger.
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Don Day
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Adapting an 8"x10" Korona view camera for 11"x14" wet plate

Post by Don Day » Thu Nov 01, 2018 2:22 am

Last summer while antique shopping out in West Texas, I asked a dealer about old lenses and he pulled out a large, dingy lens on a 6 inch square lens board. It made an image, but I could not tell what optical design it was just by that incidental inspection. It was marked for $4000 (a sucker is born every minute, right?), but I told him I'd be happy to walk out with it for $300. He said how about $500 and I said deal. Once I got back home with it, my research showed it to be a Voigtlander & Sohn #4 "pre-Euryscop" from about 1879. This is a Rapid Rectilinear of 14.5" at f/6 (these are normally built at around f/8). So although it was not the Petzval find of a lifetime, the dealer and I did not do badly by each other--these have sold for both more and less than our deal. It is perfectly all right for studio portraits as well as for landscapes.

I learned also that the lens can handle up to 11"x14" fields when used stopped down (via a Waterhouse slot) or close up (the cone diverges enough to reach the corners in this case). I recalled a friend's suggestion one time that I might consider adding a rear adapter to my 8x10 view camera for large format, so I went to work. A 12"x12" wooden "canvas" from a hobby store was perfect for mating to the rear of the view camera. I cut up some luan plywood paneling to build the extension box, and quickly hacked together this extension. I decided to model the back side to accommodate the frame of an 11x14 picture frame from Dollar Tree since I knew that item would be a stable source of good, thin glass for wet plate coating. What was missing, though, was an actual working design for a plate holder and focuser.

Earlier this week, as I gazed on the flimsy plastic frames I had liberated this plate glass from, I realized that I could stack two frames (secured firmly together by 3 #4 brass screws per side) as the cassette and use the gap in between as the guide for a dark slide. I used a table saw to dado a wide cut across the end of one frame for inserting the dark slide. Likewise, I could stack another two, and I had my ground glass adapter. The backing cardboard could be used as the dark slide since it was already cut to fit. A pair of the hanging hooks doubled as spring clips to keep the contraption in place. And Dollar Tree sells kitchen cutting mats, 2 for $1, that are 11x14" with a matte surface that drops right into the focusing frame like it was made for it. Today I got to try out this cheapo hack, and it did its job like a champ. My first effort was slightly underexposed, but it proved the concept of using an extension back to get new use out of a smaller view camera. This was also my first large format pour, harrowing to step up to but exactly like using the smaller sizes in practice.

When I researched extension backs, I got a confirmation of the design from a Blair Reversible Back from the 1890s. I would do a few things differently next time, but that won't be until something breaks.
Camera from front.
Open plate holder, just two frames stacked and joined. A foam sandwich closes the back good enough--no light leakage that mattered for slow collodion.
Glass ready for pouring. It must be clean, clean, clean for the collodion to stick.
Plate in sensitizer. The whitish color is from the formation of silver halides in the collodion surface.
Camera from behind during exposure. Note the hanging clips used in a new way.
Image in fixer.
Varnished and backed ambrotype (with a ninth-plate test shot that had better exposure--sunlight changed between setups!).

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Re: Adapting an 8"x10" Korona view camera for 11"x14" wet plate

Post by alexvaras » Thu Nov 01, 2018 6:50 am

Amazing Don, thank you for sharing! :)

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Re: Adapting an 8"x10" Korona view camera for 11"x14" wet plate

Post by PFMcFarland » Thu Nov 01, 2018 11:21 pm

That's a great hack, Don. Looks like you got a good lens too.

Waiting for the light

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Re: Adapting an 8"x10" Korona view camera for 11"x14" wet plate

Post by Brazile » Fri Nov 02, 2018 6:27 am

Well-bodged! I did something similar last year for dry plates, but I want to refine it next year, after I get my workbench project finished.


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