How I made my own 4 x 5 slide projector on a budget

Jul 6, 2021

Cheng Qwee Low

We love it when our readers get in touch with us to share their stories. This article was contributed to DIYP by a member of our community. If you would like to contribute an article, please contact us here.

How I made my own 4 x 5 slide projector on a budget

Jul 6, 2021

Cheng Qwee Low

We love it when our readers get in touch with us to share their stories. This article was contributed to DIYP by a member of our community. If you would like to contribute an article, please contact us here.

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I have been shooting 4 x 5 color transparencies or commonly known as color slide film for many years but the best that I could enjoy them was to put them on the light table and viewing them through a loupe. Unlike my 35mm and 120 slides, I have never seen them projected big simply it is not easy to locate a 4×5 slide projector.

For the last few years, I tried searching online on how to do it yourself (DIY) and build a 4x 5 slide projector but no one seems to have made them before.   There are commercially produced 4×5 slide projectors although I have never seen one in real life. I have not even seen them on the used market on eBay before but even if they are available they are going to cost a lot and even more to ship.

4×5 slides on a light table

It was only recently that I saw this YouTube video by DIY Perks on how he made a 4K LCD projector that triggered me to think about making a 4×5 projector again.  in this video he explained how he made use of the Fresnel lens instead of the conventional thick condenser lens.

Afghan Box Camera

With this new knowledge, I started to think about how I can convert my Afghan box camera into a slide projector. For those who do not know the Afghan box camera, it is a camera and darkroom built into a single box. If you need more info on how to build one you can refer to this amazing ebook by Lucas Birke on his Afghan box camera project.

Light source

Philips 12B LED light bulb

The most important part of the side projector is a powerful light source. The conventional projector will use a powerful but hot incandescent or halogen light bulb. However, for this project, I went to the store and find the highest wattage LED Bulb.  This turned out to be a 12 watts LED light bulb from Philips. It is also warm light which is what slides are usually projected with. It was said the slides usually come with a blue tint to balance out the warm light.

I wired with up with a socket (WARNING: live wire is involved. DO NOT do this yourself if you are confident or trained. ) and attached it to the back of the box camera using 2 screws.

Fresnel lens

Fresnel lenses sold as magnifying sheets

I went online and bought 2  magnifying reading  sheets  that are usually use for reading but I guess they would work for this purpose. On every sheet, there will be one side that is made up of the Fresnel lens which is a series of concentric circles and the other side will be smooth so it is important the place that sheets in the right orientation.  The one nearest to the light bulb has the Fresnel lens facing away from it and the other piece will have the concentric circles facing the bulb. In this manner, the light from the bulb will be collimated By the first piece and converged by the second piece.

It is also important to find out the true focal length of the Fresnel lens. The DIY perks video shows you how. My 2 lenses have a focal length of 90mm.

Fresnel lens separated by a narrow strip of plywood

To mount the lenses I just got two pieces of plywood with a window cut in the center and I  3D printed some corners to mount the lenses to the plywood. To attach the 2 Fresnel lens plywood in the Box camera I just use 2 narrow strips of plywood and 2 elastic bands to act as a spacer between the 2 boards. The idea here is to be able to convert this back to a box camera instead of turning it permanently into a slide projector.

Lenses

Fujinon 210mm lens

For lens, I continue to use my Fujinon 210mm lens which is my large format photography shooting lens. I find that it still does a decent job in projecting the image however I’m not sure if there is a difference in projection quality if I were to use an enlarger lens or projector lens.

Focusing

In order to focus the image on the screen, I use the focusing rods that is already part of the box camera system. This box camera is designed to take 5×7 inches photo negative so I removed the existing ground glass and made a 4×5 slide mount to hold it to the holder and to block off excess light.

Testing

Fully projected
Finally, I saw my 4×5 slides big!

For testing, I set up a piece of 5feet white fabric backdrop mounted across two light stands and was placed to see about 3 meters from the slide projector in a dark room with all the lights off. Hooya! I was able to get a good image on the screen! I was certainly very impressed and I to be able to see my large format slides on such a big screen finally!

Conclusion

While this slide projector is not bright enough to be used in an auditorium, it is good enough for a personal viewing of 4×5 slides at home. You will need a very dim room to enjoy the slides at a view distance of 3 meters. There is certainly room for improvements but that will be for another DIY made.

About the Author

Cheng Qwee Low has been doing photography including traditional darkroom printing since 2003. He started shooting using film cameras using the 35mm film format. After dabbling in digital photography, he found himself being drawn back to film photography a few years ago. This time he is attracted by the large negative size offered by a large-format camera.

At the same time, he started to explore deeper into the roots of photography and the various 19th-century photographic processes. Through the various manuals, books, websites found on Internet, he managed to learn the wet plate collodion photography and Kallitype Printing process on its own.

You’ll find more of Cheng’s work on his website and YouTube channel. This article was also published here and shared with permission.

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