Photographer Mathieu Stern tests out a lot of weird lenses. From modern CCTV to 135 year old large format lenses, nothing is too large a challenge. Many modern lenses have adapters available for all kinds of camera system. Not so much with older or more obscure lenses. So, how does he fit all these to his modern DSLRs? In this video, Mathieu’s going to let you in on one of his tricks. This helps him figure out how he can build his own adapters for these lenses. It’s an interesting technique, and once you understand the principle, making a solution is simple.

The biggest issue when trying to fit lenses is the distance between the back of the lens and the film plane (or sensor). This is called the flange distance, and it varies from manufacturer to manufacturer. Nikons have a huge flange distance. This is why most commercial adapters require diopters to restore infinity focus. Small mirrorless cameras like Sony have a very short flange distance.

Assuming the lens you wish to use as a larger flange distance than your camera, you need simply calculate the difference. This tells you how long your adapter needs to be in order to give you the full focus range of the lens. When you are projecting onto the white paper or card, you’ll want to focus your lens to infinity. You’ll also want to make sure the scene you’re projecting is also at infinity. There’s no point setting it to infinity and trying to project something a metre or two away. How do you actually go about making the adapter? Well, you can cut a cardboard tube, as shown in this video.

Or, you could also 3D print something (use black) to go between the lens and camera body. You’ll probably want to hunt around eBay for a couple of cheap broken lenses you can recycle the mounts from, too. So, if you’ve always wondered how to figure out flange distances to make your own adapters, now you know. Do you make your own lens adapters for old or weird lenses on modern equipment? Do you use this method? Or do you have other tricks? Let us know in the comments.