This is one of those fast easy inexpensive projects that didn't turn out completely adequate due to my not having thought the project all the way through... as you'll see shortly.
The standards on my Cambo 5x7 don't draw close enough to use very short lenses without a recessed lensboard. I want a recessed lensboard to use an old 4 3/8" Tessar. Because my Cambo uses a large lens board (approx 6.25" x 6.25") I figured I had adequate room to make my own. After some consideration, I decided to try using a tuna fish can rather than try to accurately cut all the little pieces needed to build a box-like recess.
This 12oz tuna can measures about 4" in diameter and about 2" deep. That seemed big enough to accommodate the lens and small enough to fit the lensboard with room for my fingers to set the shutter. Also, it is shaped like a perfect cylinder (straight sides) but has a ridge at the top which can be conveniently used as a stop and light block.
I used an old clipboard (Masonite?) as the base material. It was the right 1/8" thickness for the lensboard and is easy to cut. I used a router to cut the channels used for the light trap: I did those router cuts freehand, so you'll notice the wavy cuts! Yea, sloppy...
I used a drill press with an adjustable hole cutting bit to cut the large hole for can.
I took a chance and used a Forstner bit to cut the lens hole in the can... the metal is soft enough that the cut went easy and didn't seem to damage the bit (designed for wood).
I used some construction Gorilla glue to glue the can to the board. As you can see, I also added a wire for strength and added light blocking, pushing it down into the glue (though it probably isn't necessary). When dry I spray painted with a coat of primer then a coat of flat black paint.
I also made a couple of paper washers to use between the lens and tuna can... the metal is thin and smooth and was difficult to tighten the jam nut enough to stop the lens from turning without them.
Looks not bad: it is light tight and very sturdy!
However, here's the catch: I failed to account for the space needed for a cable release! Duh! Even the angled adapter doesn't have enough room. IF I had made a square box for the recess I could have used the extra space in a corner for the cable release... Hah!
I might still be able to use it in my case: since I do long exposures I can just do the ol' lens cap shutter trick... but what a PITA!
I hope this writeup helps someone else, or at least provides some amusement for you guys that are so skilled making your own gear. If you can point to instructions for making a better recessed lensboard, then that would be great.
Keith Ostertag
The standards on my Cambo 5x7 don't draw close enough to use very short lenses without a recessed lensboard. I want a recessed lensboard to use an old 4 3/8" Tessar. Because my Cambo uses a large lens board (approx 6.25" x 6.25") I figured I had adequate room to make my own. After some consideration, I decided to try using a tuna fish can rather than try to accurately cut all the little pieces needed to build a box-like recess.
This 12oz tuna can measures about 4" in diameter and about 2" deep. That seemed big enough to accommodate the lens and small enough to fit the lensboard with room for my fingers to set the shutter. Also, it is shaped like a perfect cylinder (straight sides) but has a ridge at the top which can be conveniently used as a stop and light block.
I used an old clipboard (Masonite?) as the base material. It was the right 1/8" thickness for the lensboard and is easy to cut. I used a router to cut the channels used for the light trap: I did those router cuts freehand, so you'll notice the wavy cuts! Yea, sloppy...
I used a drill press with an adjustable hole cutting bit to cut the large hole for can.
I took a chance and used a Forstner bit to cut the lens hole in the can... the metal is soft enough that the cut went easy and didn't seem to damage the bit (designed for wood).
I used some construction Gorilla glue to glue the can to the board. As you can see, I also added a wire for strength and added light blocking, pushing it down into the glue (though it probably isn't necessary). When dry I spray painted with a coat of primer then a coat of flat black paint.
I also made a couple of paper washers to use between the lens and tuna can... the metal is thin and smooth and was difficult to tighten the jam nut enough to stop the lens from turning without them.
Looks not bad: it is light tight and very sturdy!
However, here's the catch: I failed to account for the space needed for a cable release! Duh! Even the angled adapter doesn't have enough room. IF I had made a square box for the recess I could have used the extra space in a corner for the cable release... Hah!
I might still be able to use it in my case: since I do long exposures I can just do the ol' lens cap shutter trick... but what a PITA!
I hope this writeup helps someone else, or at least provides some amusement for you guys that are so skilled making your own gear. If you can point to instructions for making a better recessed lensboard, then that would be great.
Keith Ostertag
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