gonna start building box cameras ...

[jnanian]

i have bought enough of them ( they are my fav! )
but now i am gonna start to build them.
i am gonna make 4x5 and bigger ones
with a hinged out back to hole paper or plate
that can be removed ,,, i know anchoroptical
but have had a heck of a time figuring out what meniscus
lenses they make / sell will cover a certain image circle.

does anyone have experience with meniscus lenses or
+/- diopters enough that they know the focal length or
the image circle they project ??

thanks in advance for your help!

john

[Rick A]

Take a close look at the box cameras you already have, and measure them. They probably are all pretty close in size, and shouldn't be too hard to extrapolate to 4x5 dimensions. Sounds like a fun project, do you have any spare single elements laying about that you can start with? I'm sure you could use some of the info from pinhole cameras to work this one out. I might have to play with this one myself, just to see what happens. Never know, might end up with a great camera in the process.

Rick

[Rick A]

Just thinking-- do you have any large magnifying glasses? that might be useful as the meniscus, then play with different drilled apertures and focal lengths until you hit on the one you like best. Maybe interchangable apertures panels that slip in behind the lens. Also, use a 'box in a box'' adjustable focal length.

Rick

[Barry S]

John--Usually, you'd start by thinking about the angle of view you want and choose the focal length to match the format. Let's say you want a normal lens for 4"x5". The diagonal for 4x5 is about 6.4" or about 160mm. You can use this handy table by dividing the diagonal of the format by the focal length of the lens to get the angle of view. http://tinyurl.com/yg7689m

A reasonable lens diameter (largest aperture) would be something like 1/4 to 1/6 of the focal length. For a 160mm lens, something in the 25mm to 40mm range for the lens diameter would be fine. If you want to reduce aberrations, you'll need to make a stop to stop down the lens to at least f/16 (focal length/stop diameter=aperture). The stop should be placed in front of the lens at a distance of about 1/6 of the focal length.

A single element lens will usually *illuminate* a very large image circle, however, as you move away from the center--the performance will degrade. You can start with positive meniscus, plano-convex, or bi-convex lenses--they'll all form images. For a little more money, an achromatic doublet is an excellent starting lens. Diopter is 1/focal length (in meters), so a 160mm lens would have a diopter of 1/.16= 6.25. Have fun!

[Loris Medici]

For more information, I highly recommend Alan Greene's "Primitive photography: A Guide to Making Cameras, Lenses, and Calotypes". (Google books page: http://bit.ly/ceDEqP)

[Cainquixote]

i'm glad you started this thread.

I'm getting ready to do the same thing with 8x10 and liquid light covered glass sheets.

I never thought about a hinged back for the plates. Most of what i've doodled has had a nested back design.

[Steve Smith]

I have sketched out plans for a 5x4 box camera but I have not started to make it yet (just as well as I have many other half finished projects already).

I was thinking of using a 135mm lens fixed at hyperfocal distance for about f16. I have also thought about a 5x4 TLR!


Steve.

[jnanian]

thanks for your inputs!

i have to look better at the little lenses that i harvested off the boxes i have ..
they seemed like single cell, but who knows maybe they are something different ?

i've made backs out of cardboard and they work amazingly well for paper ( too light for glass ) plates.
i was thinking a ridged piece and a pair of clips to hold the back in place.
kind of like how a reducing back is held onto a modern camera ...
or may be sliding things like a graflock back ...
and maybe a primitive viewing screen or just a V on the top of the box to point and shoot.
i wish i had the wherewithall to make some sort of a guillotine shutter system
but THAT would be too complicated and too much fun ( just takes shim stock and a pokey thing )
so i have to figure out a way to easily cover and uncover the (recessed) lens without shaking the box too much ...

john

[Joe VanCleave]

I've made several box cameras over the years, the most recent one being a nested box arrangement constructed of black foamcore board, mounted on a bottom plate of plywood. The front half is larger than the back half, and is permanently attached to the baseboard, the back half slides in and out of the front, for an effective light seal. I've used a 2-element coated 50mm diameter, 150mm f.l. binocular objective lens (f/3 wide open), and also using a plastic credit-card sized fresnel magnifier. Both of these variety suffer from severe off-axis abberations, the fresnel being worse, but can be tamed if adequately stopped down. For moody portraits, they to look nice rather wide open, however.

For timing the exposures I use a hand-timed lens cap, with the caveat that I'm shooting grade 2 B/W paper negatives with a working exposure index of 12; in bright daylight it's a bit iffy, since the meter-recommended exposure times can be less than a second; in this situation I typically stop down to >f/50. For indoor exposures these lenses work good with wider apertures, typically 10-20 seconds in a brightly lit room.

My latest idea is an 8x10 camera that will accept Riteway-style sheet film holders, with a fixed focal distance, using a single miniscus lens stopped down to about 3mm aperture (roughly F/80-ish). The idea is to set up the lens for a hyperfocal situation, for landscapes. Thus, no viewscreen needed for focusing, just viewing dots on the sides and top (with which I've had good success in pinhole cameras). My plans are to position the lens with the concave side toward the subject, aperture in front, and use a form of guillotine shutter that operates internally, permitting placement of yellow/orange filters over the lens if desired.

I'd like to eventually make a collapsing camera with a bellows arrangement, but for now it's a box camera.

There are lots of box camera idea available at the George Eastman House online museum of old photographic equipment, here.

~Joe

[greybeard]

so i have to figure out a way to easily cover and uncover the (recessed) lens without shaking the box too much ...


You can make a really simple sector-type shutter to uncover and then re-cover the lens, using nothing more sophisticated than a coping saw and drill. Imagine a disk with a hole the size of your lens opening, and a spring that wants to rotate the disk; a projection on the edge of the disk is held by a stop on a pivotinglever, with another stop to "catch" the disk when the shutter is "open". Pivoting the lever back the other way will let the disk rotate far enough to "close" the shutter and catch on a second stop, exactly like the escapement action in a mechanical clock. A slight elaboration will allow you to keep the shutter from re-opening when you cock it, but if you are using plateholders or a darkroom-loaded camera, that isn't a problem.

I made something like this as a kid, using scraps of countertop Formica (the thin stuff that you glue down, not the melamine-clad particle board that you see now) but thin aluminum or even wood could be used.

Sounds like a fun project to do with the grandson in a couple of years.