Mirrorless camera owners in search of fast glass and razor-thin depth of field have a new king of wide-aperture lenses to drool over in the form of the Handevision IBELUX 40mm f/0.85. It's the fastest volume production lens in the world, and the manufacturer claims it'll give you an image similar to an f/1.2 lens on a full frame camera.

Designed in Germany and manufactured in China, the Handevision IBELUX 40mm f/0.85 lens joins gear like the Voigtlander 42.5mm f/0.95 in the rarified territory of lenses with apertures larger than f/1.

What does that mean? Aperture is expressed as a ratio; it's the ratio of the lens's focal length to the diameter of the iris opening. A lens with an aperture lower than f/1 has an aperture that's physically wider than the focal length. It can suck in a lot of light in low-light situations, but it will have a very shallow focal plane, so objects that aren't directly in focus will be very blurry.

The widest aperture lenses ever made were a series of 10 Planar 50mm f/0.7 lenses that Carl Zeiss built for NASA in the 1960s. They were famously used by Stanley Kubrick to film the signature candlelight scenes in Barry Lyndon.

Super wide aperture also means "super expensive." In this case, a fair bit more expensive than, for example, the US$999 Voigtlander above. The IBELUX 40mm has a MSRP of $2,080 – so if you're sticking it on a Canon M, it's nearly six times as expensive as the camera. It's also a heavy and bulky lens at 1.15 kg (2.5 lb) and 128 mm (5 in) long.

Still, soft background bokeh is hard to achieve on smaller sensor cameras, and the test images in the gallery look quite nice. The manufacturer rates the sweet spot at f/5.6 for maximum sharpness.

The IBELUX 40mm f/0.85 is available in Sony NEX, Fuji X, Canon M and Micro 4/3rds mounts.

Source: Kipon