Foamcore 8x10

[Daire Quinlan]

Finally finished my 8x10 that's been sitting idly in a press for quite a while. I spent ages trying to assemble some sort of complicated clever way of holding in the ground glass and film holders, eventually I settled on rubber bands

Takes normal 8x10 film holders, 300mm Industar 37 in front of a Sinar leaf shutter, all bolted onto nested foamcore boxes that do the job of focusing. Unfortunately shooting it and developing the subsequent sheets is a bit time consuming so I've only really had a chance to go through a couple of shots just to verify it was actually working. Nothing quite like a negative 8 inches by 10 inches in size

Here's the beasty itself, more notes on the flickr page if you click through.



Here are a couple of test shots:




Incidentally, taking shots of red flowers under tungsten light with B&W paper is never going to be an ideal situation ... 32 sec for one of them at f/4.5 :rolleyes:

[Steve Smith]

Excellent!

I have some plans in Autocad format for a 5x4 film holder spring back which could be stretched to 8x10 size. If you would like a copy, PM me with your e-mail address.

However, rubber bands work fine and are what I used on my first camera before I rebuilt it with a spring back.



Steve.

[Toffle]

Looks great to me. Congratulations on your success so far.

[Mark Fisher]

Nice...it also looks familiar. I did something similar to experiment with home made lenses (on flickr under "fotofish"). I really like the idea of using the Sinar shutter. I have no idea what a sinar shutter looks like and what would be involved in using it, but it looks like it solves the problem of using regular films. Well done!

[Daire Quinlan]

Thanks all. The couple of shots there were just quick ones. Hopefully I'll get some portraiture done over the weekend, that's where this really ought to shine. @Steve Smith, Thanks, the real problem is trying to get the materials though. My original design had a system of spring loaded posts to apply tension to the ground glass and the film holder when it was slipped in. I spent ages trawling hardware stores looking for the right bits and never really finding them, or some sort of leaf spring equivalent so I could make something a little more conventional. Eventually I got tired waiting. Hence the rubber bands :-) @Mark Fisher, sinar shutters are basically big leaf shutters that sit behind the lens. They're actually designed for Sinar monorails (f2 ? Norma ?) where they sit between the front standard and the bellows, and sinar lenses are mounted in the front. They have relatively standard lensboard like mountings on them though so they're easy to adapt.

[Steve Smith]

@Steve Smith, Thanks, the real problem is trying to get the materials though. My original design had a system of spring loaded posts to apply tension to the ground glass and the film holder when it was slipped in. I spent ages trawling hardware stores looking for the right bits and never really finding them, or some sort of leaf spring equivalent so I could make something a little more conventional.

I have heard of people cutting up stainless steel cooking spatulas to make flat springs. Hacksaw blades work too!


Steve.

[Mike Wilde]

Nice project, and images. I use foam core for all sorts of things. My heart kind of skipped a beat when I thought - you can get it that big? At work we get it in in cases of 24 sheets of 4'x8' at a time, and I was pretty sure that was the largest boards sold.

[Daire Quinlan]

Nice project, and images. I use foam core for all sorts of things. My heart kind of skipped a beat when I thought - you can get it that big? At work we get it in in cases of 24 sheets of 4'x8' at a time, and I was pretty sure that was the largest boards sold.

I think the largest board I got was much smaller than that, maybe 2' by 4' or so I don't think any of the pieces used in the camera are bigger than about 12" on the long edge.

[Leo_P]

Better quality wiper blades - the sort fitted by the factory - have two steel springs in the rubber. They just pull out and are about 3mm / 1/8" by however long your blades are. I've been collecting them for years for a 5x4 that I've never made. Another possibility is piano wire. I've just used some to make a spring for an Ikoflex. It comes in various gauges, I got mine from a model shop.

[Vaughn]

What a fun project! Makes me wish I had a 14x17 film holder laying around here as I have a bunch of 14x17 x-ray film!

Vaughn

PS Our local hardware/lumber store has 4'x8' foam core -- stacked right along with the sound board and plywood.