“Every photographer has different needs when it comes to lenses — in price, speed, and focal length. The Pixels and Prisms 163mm f/2.5 telephoto lens is a customizable optical system that offers a low-cost, open-source alternative to commercial lenses through 3D printing,” Steele explains.
“As a photographer, the experience of building this lens was a valuable method of connecting with the principles which underlie much of my work. When a change in lens design affects your depth of field or sharpness, you develop an acute understanding of, and appreciation for, the equipment and techniques that you employ,” he adds.
Features of the lenses
The 3D-printed lenses include a manual focusing mechanism that can lock in the fully-extended or fully-retracted positions like normal lenses do. The latter is the first for a 3D-printed lens designed around a full-frame digital camera system.
“For under $15, Pixels and Prisms is a viable low-weight lens option for travel, portrait, or street photographers, as well as a cost-effective entry point into telephoto photography. The aperture and zoom system can even be modified to work with any lens element, so long as an extender is added to the front of the optic,” he continues.
“The process of designing and creating this telephoto lens was a three-month endeavor that started with the creation of an optical formula. The print files are open for you to download — and the following will allow you to source and fit a lens element to go with them,” Steele explains.
How does it work?
“First, balance the lens upright (on its edge) on a table or desk. Then, position a light source on the other side of the room, and direct it towards the lens element. The lens will focus the light at some point above your surface. The exact point is easily located by moving a sheet of paper to and from the lens: a halo will appear that drifts in and out of focus as you move the paper. Finally, mark the point of the sharpest focus and measure the distance from the lens element. This is your focal length (although I would recommend double-checking your calculation),” Felix Steele explains the working principle of the lenses.