What Happens When You Put the World’s Blackest Material Inside a Lens

Photographer Mathieu Stern is known for his fun projects like turning a Parisian apartment into a giant camera and shooting travel photos with a full-spectrum converted Sony camera, often shoots with vintage lenses. Stern significantly improved one by putting the world’s blackest material inside it.

While older optics can deliver interesting images, they often struggle with contrast, flare, and ghosting due in part to internal reflections. To combat this issue, Stern put the world’s blackest material, which he has previously used to great effect as an incredible portrait backdrop, inside a lens.

The lens in question is a cinema projector lens. The rare prime lens has a 70mm focal length and f/1.6 maximum aperture. It is quite a beautiful lens, and its images demonstrate a ton of character.

“I love to use vintage projector lenses on my full-frame camera because these lenses can create dreamlike images with breathtaking swirly bokeh,” Stern explains. “But one big problem with any projector lens is that they were not made to capture images but to project images.”

Like the one Stern has, the inside of many projector lenses features shiny metal to reflect light, which is perfectly fine for image projection. However, when light goes the other way — into the lens, rather than out of it — the image is washed out and lacks contrast.

Stern has often corrected this problem during photo editing, as adding contrast to an image is a relatively straightforward thing. However, capturing a better image in-camera is ideal and results in less work. So, it was time for Stern to solve this longstanding issue and see what image quality his lens was capable of.

Flocking, the process of putting many small fiber particles on a surface to reduce its reflectivity, is common in photography. Photographers will be familiar with flocking if they have looked inside some lens hoods, which can include a velvety, black fabric material. It’s also common to find flocking inside bellows or with certain film cartridges.

In Stern’s case, flocking a lens hood won’t cut it because the inside of the entire lens barrel is highly reflective. Like with the backdrop project he did, Stern returned to the Japanese company KoPro to get the perfect material.

After taking the projector lens apart, putting KoPro’s incredibly black material, which absorbs more than 99% of visible light, and piecing the lens back together, did the DIY project work? It sure did. The results are incredible, as demonstrated in Stern’s video above.

To see more from Mathieu Stern, visit his website and YouTube channel.