The widest lenses currently available cover 180 degrees, but a team of optics geeks just designed a custom fisheye lens that can see 270 degrees — which includes some of the space behind the camera. Lensrentals founder Roger Cicala recently shared a look at a custom prototype lens created for C-4 Optics. The C-4 lens isn’t likely to head to camera stores anytime soon — but what photographer doesn’t want to geek out over a 4.9mm f/3.5 circular fisheye lens, the widest fisheye lens yet?
The Lensrentals team has deconstructed a number of different lenses, but building one from scratch is a bit more complex. The lens doesn’t have an autofocus motor or stabilization, so the lens is all mechanical. Lensrentals says the lens is designed for immersive video and “specialty shots.”
The group began with the smallest lens element, working their way up to the large front element (which costs $5,000 alone). The lens is so large, it’s built into a giant support plate.
The most complex part of the lens? The main barrel, which contains the actual aperture of the lens. Several pieces are integrated into the main barrel before it is added to the rear of the lens. While there is no autofocus, a focus barrel is also part of the lens, with a built-in ring lock so the focus can be locked in at infinity.
Putting everything together, the aperture fork and aperture ring, for adjusting the aperture, are mounted together. Then come several more pieces for the rear of the lens, including a bayonet mount. The aperture is then calibrated before finishing assembly.
For the front of the lens, the front element — that large rounded glass at the front, sits on a retaining ring. The front is then added to the set of rear elements. Then the whole thing gets three legs and a platform to support the weight of such a big lens, which tips the scale at more than ten pounds.
Along with Cicala, the team constructing the lens also included Aaron Closz, Brian Caldwell, and Wilfried Bittner.
The widest known lens before the prototype is a vintage Nikon 6mm f/2.8, capable of capturing a 220-degree view. Lensrentals says the 1970s 6mm lens sells for around $100,000 — the prototype lens would cost less than half. For more of the details on how the lens was assembled, head to Lensrentals’ recap of the assembly process.
