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Pentax HD FA 31mm f/1.8 Limited

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Prime lens

A prime lens by Pentax for Full frame cameras, 31mm f/1.8. Same optics as the earlier smc FA 31mm Limited.

MakerPentax
Focal length31mm (prime)
Maximum aperturef/1.8
Made forFull frame sensors
MountsPentax K
Stabilisedno
Autofocusyes

What it frames like

142435508513520040080031mm equiv.31mm
Its full-frame-equivalent focal length on the sensor it was made for.
Full frame 31mm · 60°APS-C 46mm · 42°
How wide 31mm sees on each sensor it covers.
f/1.8
f/1.8 wide open, to scale against f/1.4.
  • On full frame (Pentax K): as marked, 31mm.
  • On APS-C (Pentax K): like 46mm on full frame; f/1.8 gives about the depth of field of f/2.7 there.

Cameras it fits

Questions people ask

See what it frames: its view on the Pentax K-3 Mark III Monochrome at any distance, and its depth of field, drawn to scale.