Why are lenses so expensive? Watch this Swedish inventor design his own Pretzeval

Mats Wernersson made his first camera when he was just 10 years old — and his latest project may just help photographers appreciate their lenses just a bit more. The Swedish camera designer has built a 90mm Nikon-mount lens almost from scratch.

Wernersson, who, with a few camera patents to his name, isn’t your typical photographer, complied the entire process into a four-minute video. The lens is a 90mm f/2.8. As a Pretzeval type lens, it’s designed to swirl the background bokeh, he says.

Creating everything but the lens mount, diaphragm blades, and helicoid from scratch, Wernersson shaped and polished the glass pieces, which he sourced from Surplus Shed, before painting the edges black to prevent light leaks. Even the lens barrel started out as a single piece of metal. Ball bearings help adjust the diaphragm — which he pulled off an old Pentax lens — to different apertures.

While the lens is homemade, Wernersson’s process (and wide variety of accessible tools, including a grinding machine, lathe, and mill) almost makes the lens blend in with the store-bought options, except of course for his name on the front.

Wernersson describes his optics as “just a lazy hobby” but the meticulous work goes beyond what most hobbyists would attempt. Wernersson has also crafted his own cameras for infrared, astronomy, macro, panoramas — even a 3D camera and a light field camera that allows for focus adjustments after the shot. He has a number of patents ranging from autofocus to wireless flash and optical displays. He also received both the inventor of the year and invention of the year awards from Sony Ericsson in 2005.

While making your own lens may not be an easy DIY project, the video, at the very least, shows the kind of work that goes into making a single camera lens — making the price tags on the commercially available versions seem a bit more palatable.