Handevision HVIB4085CM IBELUX 40mm f/0.85 High-Speed Lens for Canon EOS M Digital Cameras (Black) Fastest lens for mirror less system cameras in the world Solid, durable lens construction comprised of anodized aluminum, brass, and stainless steel Ten high-precision iris blades open up circularly to produce stunning, unique bokeh Superb low-light performance eliminates need for flash in darker environments Construction: 10 elements, 8 groups