How to create autofocus with a 120 year old lens

Mathieu Stern’s at it again with his crazy experiments. This time, he’s taken the lens off a 120 year old folding camera, and attached it to his Sony mirrorless camera. This is nothing new, but what is new is that he’s given it autofocus abilities.

The first autofocus lenses were released around 40 years ago, so this is quite the feat. He used an ingenious adapter designed to give autofocus abilities to manual focus Leica lenses on the Sony A7 range of bodies. Mathieu then modified the adapter to fit this 120 year old lens.

The first step is figuring out the exact distance on the original folding camera between the lens and the film plane when focused to infinity. This allowed Mathieu to create a set of tubes which would then go between the adapter and the lens element. Getting this distance accurate is critical, so that the lens can continue to infinity on the digital body.

Mounting the tubes to the Techart Pro adapter then adds the extra little distance it needs to retain infinity focus. Once everything is attached, the camera’s AF signal is sent through to the adapter which moves forward and backward in order to focus.

Although the adapter was created to let users autofocus Sony bodies with Leica lenses, it should work with anything, in theory. There’s no communication between the camera and lens, so putting in tubes doesn’t disrupt any signals.

This means, then, that anything you could get to fit on a Leica could also be used with this. Like M42 or other types of lenses. Except, now it’ll have autofocus capabilities.

It’s a cool idea that provided Mathieu with some rather impressive results.

You can check out a few more examples over on Mathieu’s blog and at the end of the video above.

Have you used the Techart Pro adapter with your camera? Have you just used it for its intended Leica recipients? Or have you modified it to work with other lenses? Do you think you’ll pick one up now, having seen how well it works? Let us know and tell us what you think in the comments.