Best 8mm fisheye lenses with f/1.8 aperture

Top pick: OM System M.Zuiko Digital ED 8mm F1.8 Fisheye PRO. It's the only true 8mm fisheye at f/1.8 I found, and that fast aperture is the whole point — handheld in dim light, and a 180° view on a Micro Four Thirds body. Weather-sealed and sharp wide open: the obvious choice for night skies, tight interiors and skate/sports shots.

Who the others suit:

• The Olympus-branded version of the same lens — identical optics, so take whichever listing suits you; a refurbished copy is the cheaper way in.
• The bundle version — same lens with extras, for anyone who wants it all in one order.

If f/1.8 is non-negotiable, this is the lens; the 8mm f/2.8 and f/3.5 fisheyes from Rokinon, Samyang, Tokina, Laowa, Panasonic and Sony are the fallbacks when you can trade speed for size or a zoom.