Metabone's Devil Speed Boosters can give your Pentax Q an f/0.666 lens ...

WILL NICHOLLS, PETAPIXEL:

Metabones creates a whole host of lens adaptors and Speed Boosters that reduce focal lengths and boost effective apertures of lenses. Now they’ve created a new Devil’s Speed Booster Q666 0.50xfor Pentax Q cameras that will turn them into “low light monsters.”

The new speed booster allows you to mount any Nikon F or G mount lenses onto your Pentax Q camera (excluding the Nikon 2.1cm f/4 and 20mm f/2.8 AI-S lenses). Not only that but, if you attach a f/1.2 lens, you’ll end up with a “world-record” f/0.666 equivalent lens to play with (hence the “Devil” in the name). Combined with the back-illuminated sensor of the Pentax Q, that is one good low-light performing setup right there.

Read more, here.