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Voigtlander SL 90mm f/3.5 APO Lanthar (Nikon) - Review / Test Report - Analysis |
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Lens Reviews -
Nikon / Nikkor (APS-C)
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Page 2 of 3
Distortions
Unsurprisingly the Voigtlander produces only a negligible degree (0.2%) of
pincushion distortions which is not field-relevant.
The chart above has a real-world size of about 120x80cm.
Vignetting
The APO-Lanthar is a full format lens and as such it enjoys the usual sweet
spot advantage when used on APS-C DSLRs. Within this scope the lens shows only a slight
degree of vignetting at f/3.5 and from f/5.6 onwards it's a non-issue.
MTF (resolution)
The Voigtlander is a fairly unambitious lens - it is a moderate tele lens with
a comparatively slow max. aperture yet it takes advantage of one "APO" element.
Correspondingly the resolution characteristic is on a very high level straight
from f/3.5. The center resolution is excellent here and the borders follow on
very good levels. At f/5.6 the center reaches its peak and the borders
improve to excellent quality. The lens shows its best borders performance at f/8.
Diffraction effects reduce the quality from f/11 onwards.
Below is a simplified summary of the formal findings. The chart shows in line widths
per picture height (LW/PH) which can be taken as a quantity for sharpness.
The chart is limited to the visually relevant LW/PH range of [750, 2250].
If you want to know more about the MTF50 figures you may check out the corresponding
Imatest Explanations.
Chromatic Aberrations (CAs)
Typical for Voigtlander lenses CAs (color shadows at strong contrast transitions)
are basically a non-issue and not field-relevant.
Purple Fringing
The 90mm f/3.5 is not fully resistant against purple fringing (a blooming effect
at extreme contrast transitions) although the problem is still comparatively
well controlled. Here's a 100% sample crop showing some water reflections:
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