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Salvaged Circuitry

Adventures in Tinkering

Hotshoe Viewfinder

This is an example of an optical viewfinder for a camera hotshoe. This is designed to take no electric power (there are no illuminated viewfinder lines here), so If you have the right optics, all you need to do is make a shell of some kind and mount it into a standard hotshoe. This project details the procedure necessary to make a usable optical viewfinder, designed to fit into a standardized hotshoe.

When implemented, the hotshoe viewfinder will look something like this. Well, because I don't think an optical viewfinder is worth $150 USD, I am going to go ahead and try to make my own.

Here's what I'm roughly planning to build. However, implement a more elegant solution other than relying on gravity to hold an optic in place :D

The first step is to find some optics appropriate for use as an optical viewfinder. Where's a great place to find such a thing? A disposable film camera. Also, some small optics are found in digital paper scanners.

With the Kodak sticker removed, the camera is basically just held on with plastic snaps. I used a small piece of metal to open it. You could have used a flat head screw driver just the same.

Here's the plastic optical components from a kodak disposable film camera. The optics are rated for 35mm, but with a little measurements, they can be adjusted to 28mm, which is the beginning focal length of the LX3 lens.

Some measurements of the distance between optical elements in film camera.

Here's a mock up of the viewfinder on an aluminum shim.

Here's a more direct view of the viewfinder. Not too bad for plastic elements.

Because the aluminum shim I mad for the hotshoe was too thin (could not stick out of the top of the viewfinder) I had to make a new one, out of a thicker piece of aluminum. So,I grabbed an old 4gb Seagate medalist hard drive and tore it apart. What's nice about the old Seagate medalist Hard drives was that they were milled entirely out of aluminum, not like the hard drives today that are made out of thin aluminum and sheet metal. With the Seagate, I had 1/8 in aluminum to work with.

Because the aluminum shim I had made prior fit into the hotshoe of me cameras, I used it as a stencil, and drew around it, making the appropriate markings onto the thicker aluminum.

The differences in thickness really show in this picture.

I went ahead and mounted my Dremel with the routing bit attachment on top of the vice. I had to use a clamp to secure it down. If I had just put it in the vice, I would have crushed the routing attachment.

With my Fremel mounted, I began finalizing the bottom aluminum hotshoe piece. What's nice about this attachment is that you can adjust the distance of the sanding bit from the plastic table. This helps a bunch when you need to make the groove for the aluminum piece to fit properly into the hotshoe. What's really annoying is that the routing attachment is made of PLASTIC and melts when the aluminum piece gets hot. So you have to cool the aluminum piece under cold water every 1-2 minutes of sanding. Really annoying, but it gets the job done.