I'm working my way to 4x5 pinhole, and I've decided to make my first camera out of things I have on hand. Considering the miscellaneous camera crap I have laying around the house, that's not as hard it may sound. Once I decided not to deal with a shutter on this camera, my plans came together, and there was no longer any reason to put this project off.
This one is still in progress, so I thought I'd show steps without showing what the camera will look like, then wrap it up in another post once it's done.
This first picture is of thin disk of aluminum that will hold the actual pinhole. You'll have to take my word for it, there is an aluminum disk under that paper. The paper template is just a quick way of finding the center of the disk.
I cut the disk from a piece of thin aluminum sheet stock with a pair of tin snips. It's not perfectly round and the pinhole will not be perfectly centered...that's one of the things I love about pinhole. Close enough is good enough. BTW, the disk is sized to fit in to a 55mm filter...you'll see why in a minute.
The smaller disk in the upper left is the pinhole as it comes from Lennox Laser. Nice, handy package.
After drilling a hole in something near the center of my not so round disk, I mount the pinhole with aluminum duct tape. I like the aluminum tape because it is light tight and strong, yet easily removed and repositioned. Lots of room for mistakes.
This is the side that will eventually be facing the film. We'll have to take care of that shiny metal and make sure the installation is light tight. More on that is coming up.
Next, we see the parts that will be assembled into the pinhole lens-board for this project. We have, a larger aluminum disk, also not looking all that round, with a hole in the middle...you guessed it...not very round.
In addition to that disk, we have a 49-52mm step-up ring, a 52-55mm step-up ring, a 55mm uv filter, and our mounted pinhole. Why did I chose these sizes of rings/filters? Just because I had them laying around.
Here is the first part of the assembly. The 52-55mm step-up ring is placed in the hole and retained there by the 49-52mm ring. It would be more economical to use an old 52mm filter with the glass broken out...I'll have to check to see if I have an old filter I don't need any more, to save the step up ring for a higher use.
This shot shows you the pieces that make up the whole assembly. Now you see the foamie material on the film side of the pinhole disk. I've also applied a little flat black paint to cover the aluminum tape...being careful not to fill in the pinhole.
Finally, the pinhole disk rests in the step up ring and is retained by the UV filter. Now, I don't really know that the UV filter is a good idea. Looks like just one more chance to cause flare to me. I'll have to see if I have a filter I'm willing to sacrifice and maybe break the glass out it. Ideally, I'd like to find an old metal lens shade to use here. I might have something like that in a box somewhere. If not, Ritz Collectable Cameras in Phoenix as a box of stuff that's always fun to pick through.
So there we have it for now. A round lens plate with an easily interchangeable pinhole system. I've just got a few more little steps to go and you'll see the very strange camera that this will become part of.