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Voigtlander APO-Lanthar 180mm f/4 SL - Review / Test Report - Analysis |
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Lens Reviews -
Nikon / Nikkor (APS-C)
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Page 2 of 3
Distortion
As to be expected from a moderate tele lens the level of distortion is very low (very slight
pincushion distortion) and not field relevant.
The chart above has a real-world size of about 120x80cm.
Vignetting
On the Nikon D200 with its reduced format (APS-C) the (full format) lens exhibits only slight
vignetting at f/4 which shouldn't be problem in the field. At f/5.6 the issue is
absolutely negligible.
MTF (resolution)
The 180mm APO-Lanthar exhibited an excellent performance from f/4
up to f/8. Beyond diffraction effects are the limiting factor but it remains
easily usable till about f/16. The lens showed a very even performance across the frame.
Please note that the MTF results are not directly comparable across the different systems!
Below is a simplified summary of the formal findings. The chart shows line widths per picture height (LW/PH) which can be taken as a measure for sharpness.
If you want to know more about the MTF50 figures you may check out the corresponding Imatest Explanations
Chromatic Aberrations (CAs)
Low lateral CAs (color shadows at harsh contrast transitions) seem to be one of the
primary design objectives of Voigtlander lenses. At less than 0.5px on the average
at the image borders the issue is not really field relevant.
Purple fringing is absolutely absent with the Voigtlander - see this sample shot at f/4.
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