HD Pentax-D FA* 50mm F1.4 SDM AW
Vignetting
Lens vignetting is something all fast lenses show to a certain degree; in terms of design, one way to avoid it is to make the image circle of the lens larger than otherwise needed. Thus, the fight against vignetting is one of the key drivers in seeing lenses grow in size, especially with regards to their front lens element diameter.
Vignetting is one of the easiest things to correct in software such as RawTherapee or Lightroom via lens profiles. Usually one click to apply the lens correction profile is all that is needed. Some users may prefer to keep it as it is as a nice artistic element.
Pentax cameras since 2009 (obviously including the K-1 and K-1 II) have a feature which allows automatic correction of vignetting of Pentax lenses in JPG shooting.
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When looking at the results the verdict is that the vignetting is mild for a lens of its class.
Vignetting in the extreme corner is about 1.5 EV only when shot wide open. By stopping down the lens to F2 is improves further and by F2.8 it's practically gone.
Verdict: 4/5
