I just saw this really interesting new lens that Fuji released, its the XM-FL that is a fixed 24mm f/8 pancake lens that doubles as a lens cap and has built in filters. Its definitely a great concept and Fuji is on the right path to make something awesome. Too bad they couldn't of made this lens f/2.8 instead of f/8. Also its only shipping to Japan for now. Read More
How interesting! It essentially turns your x mount camera into a cell phone camera. Quite wide. Fixed aperture. Great dof. It's almost as if this were desirable.
I've seen some very interesting, older filter lenses. In fact, I just bought a PZO Janpol Color for myself as a birthday present. These lenses have two knobs that adjust color, making any enlarger into a color-capable one. I don't know if it can focus to infinity. Another pricier and bulkier lens of similar design, the Vega 22UC, is epic in terms of near field sharpness and contrast judging from the few examples I've seen. It can focus to about 20'. Some aerial lenses likewise had a variable blue/yellow filter built in.
Oly made one in a MFT mount. Fun lens, manual focus, gives the camera a non-confrontational outline .. (as in not a professional camera/lens outline). The Oly version doesn't have filters. For the lens cap mode you hit a lever and a metal "lens cap" slips in front of the lens. Wine tasting with the Olympus 15mm MFT Lens Cap lens. (EM5, f/8, 1/60, ISO 12,800)
I actually came across this lens on eBay and stopped to wonder what it was but didn't bother to look it up. Thanks for the link nerwin. It reminds me of the holga lomography lenses for Canon/Nikon bodies. For anyone interested in picking this little guy up (now considering it myself) they can be had on eBay for $70ish.