If you're a fan of interesting looking bokeh, then you'll want to check out the latest video from Mathieu Stern, the Master of Weird Lenses. In it, he creates a reverse globular lens out of cheap Russian glass to create some stunning bokeh effects that are pretty amazing in the day, but like most things in life, get way better at night.

This video might be more helpful if you're trying to get step-by-step instructions on how to do this to your own lens:

Stern uses a Mir 1B 37mm f2.8, an inexpensive Russian lens. To achieve the effect, all you really have to do is remove the front of the lens and turn it around before reattaching it. This creates an interesting look; the center will be the only thing in focus, much like a tilt shift lens, except the bokeh will look as though they're "exploding."

In the past, Stern has done the same thing with the same lens, but got slightly different results because instead of shooting at night, he shot in the day. The center was still the only part of the frame in focus, but the bokeh was much less dramatic. It still had a radial blur appearance, but it wasn't as apparent as they would be on the bokeh balls you'd see at nighttime.

Though a lens like this wouldn't come in handy very often, the effect it produces would be great for a wide range of different kinds of shots and scenes, like dream sequences, drunk POVs, or even entire avant-garde pieces. If you've got a lens that is collecting dust/you don't care about, you might want to give this a go.

Source: Mathieu Stern