Voigtlander Nokton 50mm F1 Aspherical

Reviewers of the f/1 Nokton (including the M-mount design it is related to) find good centre sharpness at f/1 with a soft, low-contrast edge to fine detail that clears quickly from f/1.4 to f/2. Corners stay behind the centre until about f/2.8, and some longitudinal colour fringing and coma show up wide open, as expected for this speed.

The out-of-focus rendering is the reason to buy it: backgrounds dissolve with very little nervousness, and the 12 blades keep highlights round when stopped down. Testers also point out the compact size relative to f/0.95 alternatives, but note that at its US list price it is far from the cheapest route to f/1.

Owners like how small and dense it feels for an f/1 lens and enjoy the smooth helicoid and the instant focus magnification on Sony bodies. Many use it as a night and portrait lens rather than an all-rounder, and the shallow depth of field at f/1 is often described as addictive.

The usual complaints are hit-rate at f/1 on moving subjects, purple fringing on backlit highlights, and the price compared with Voigtländer's own 50mm F1.2. The screw-in hood is small but some users wish it were deeper.