no need to apologise, It's always a disappointment when one sees one's wit fly heedlessly over the head of the audience, isn't it?
Keep us up on progression on making film holders. 8X10 film holders have been cost prohibitive for me as well. I've seen some for decent prices, but it never coincides with times when I have money.
This happens all too often with me.
Originally Posted by pdeeh
It may be quite a while before I get round to trying to make film holders, so don't hold your breath
But in principle I don't see it as being very difficult. What occurred to me as I held one and looked at what it does and how it does it is that it only looks complicated.
Once I visualised it as a sequence of layers of material stacked up (rather than a complex monoblock) it became much easier: consider each required element separately, and it becomes much more apparent that one can be made by glueing together the parts in layers.
So for instance, the groove in which the darkslide runs looks impossible - how do I make a groove like that? But considered as three strips of material stacked up with the centre one a little less wide than the ones above and below, it's suddenly quite straightforward.
Working out how to build the loading end seems the most complicated part, but only if one only tries to copy the way that it is implemented in a standard film holder. One has to make it light-tight and secure, so we can let form follow function. Having said that, I haven't given that bit much thought yet.
Maybe if I have a wet afternoon to fill, I might try prototyping one in foamcore. It'd be about 4 inches thick, but it would be a proof of concept.
I've no doubt others have had similar thoughts and probably if I looked hard enough I could find a few similar designs on the interwebs, but so far I only found ones built by damn clever home woodworkers with a garage full of tools. Whereas I have only a knife, a mat and steel rule
Try mat board, not foam core, for the film holder. Single weight mat board should suffice. Building up the film holder with slots for thin metal dark slides and slots for the film should result in a light and compact holder. Standard holders have a ridge that fits into a grove as a light trap. Draping a large black cloth over the back of the camera while manipulating the dark slide and exposing the film may eliminate the need for this. Taping a tab made from the same mat board as the holder to the film can serve as a handle for inserting the film as well as a light trap. A step on the tab makes an even better light trap. The tab and the adjacent surfaces of the film holder should be blackened to better block light. When loading film, you may first have to insert a piece of paper in the slot opposite the loading slot to guide the film into that slot. A knife, a steel rule, and a keen mind are most of what one needs for making pinhole cameras.
I wasn't thinking of making the final article from foamcore - far too bulky. Mat or greyboard seem the right sort of stuff.
As it happens I prototyped one this afternoon out of corrugated cardboard, just to see how it could work, and it really will be eminently possible with the right materials. I found a few ways of doing it, some more wasteful of materials but "tidier", others more fiddly but less wasteful.
Trying to make a "folding bottom" (as in a commercial film holder) seemed far too much bother. One solution is to forget about doing so, and instead simply leave the bottom of the film slot "open", but with a couple of layers of velvet ribbon as light traps. Good enough perhaps for paper (if one takes care), rather less sure about film. The bottom end of the darkslide slot can made sealed of course.
It also occurred to me that this would be an excellent project for some clever dude/dudette with a 3D printer ...
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I made one, but it was intended to use home-built lenses and standard LF lenses. I got the basic idea from the Alan Greene book and modified it so I could use standard 8x10 holders and a ground glass. The trick is to start with holder dimensions and go from there. I made it with thicker (1/2"?) black gator board (like foam core, but with a plasticy outer layer), hot melt and black duct tape. It worked really well. I don't have measurements, but lots of images of the construction details here.
I recently built a set of simple holders for paper negatives and calotypes, and one that holds a ground glass. These are one-sided single channel holders, so they are not fancy but they work and they were simple to construct out of 1/8" MDF. The holders are designed for either 8x10 or 7x11 paper negatives. They follow the ideas found here:
-- unfortunately the photos at that link no longer exist, but if you read the descriptions you can work it out. Like Mark's, mine are for use in a lensed camera. The trick is to make the distance to the GG or the surface of the paper be determined by the thickness of the MDF rather than by something you need to measure or cut, so it is consistent. For pinhole that won't matter though. With mine, the trick Jim mentioned with paper is also needed to remove the paper negatives, but it works like a charm ( thanks to my schoolteacher wife who suggested it to me... they know all the little tricks like that! )
There is a picture of some of the pieces before I glued them together in this post:
I used the "soft side" of inexpensive stick-on velcro strip as the light trap and it works just fine.
Last edited by NedL; 03-25-2014 at 10:51 PM. Click to view previous post history.
Reason: Added link to photo
Ah Ned that's interesting. You use the same slot for the paper negative and the darkslide, which is a marvellous simplification that hadn't occurred to me.
Constructing "picture frame" shapes to build a holder uses a lot of material - I think I would need 3 sheets of A3 per holder as a minimum (for a double sided holder). If one treats each side of the quadrilaterals as a separate strip, it's much more efficient (one and a bit holders per sheet), but needs more thought and of course is more fiddly and prone to error.
Mark that's a nice looking camera. Thanks for the link. I'd like to have a go at something similar one day. I actually bought the Greene book the other week but then sent it back in a fit of buyer's remorse. I'll keep my eyes open for a second-hand copy I think
And excellent for street photography as well! Nice job.
Originally Posted by Trond Kjetil
"Have fun and catch that light beam!"
Bert from Holland
my blog: http://thetoadmen.blogspot.nl
my Linkedin pinhole group: http://tinyurl.com/pinholegroup
* I'm an analogue enthusiast, trying not to fall into the digital abyss.
* My favorite cameras: Hasselblad SWC, Leica SL, Leica M7, Russian FKD 18x24, Bronica SQ-B and RF645, Rolleiflex T2, Nikon F4s, Agfa Clack and my pinhole cameras