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Pentax SMC-FA* 80-200mm f/2.8 [IF] ED - Review / Lab Test Report - Analysis |
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Lens Reviews -
Pentax
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Page 2 of 2
Distortion
The FA* 80-200mm f/2.8 produces only a slight degree of barrel distortion at 80mm (~0.6%)
and slight pincushion distortion from 135mm to 200mm. This is not field-relevant.
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Move the mouse cursor over the focal length text marks below to observe the respective distortion
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| 80mm |
135mm |
200mm |
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The chart above has a real-world size of about 120x80cm.
Vignetting
The FA* 80-200mm f/2.8 is a full format lens and when used on an APS-C DSLR
it can take advantage of a sweet spot effect here. At 80mm and 135mm
there's only a slight degree of vignetting at f/2.8 but it's somewhat more
pronounced at 200mm. From f/4 onwards the problem is negligible in field
conditions.
MTF (resolution)
The FA* 80-200mm f/2.8 produced generally very decent resolution results in the lab.
At 80mm @ f/2.8 the center performance is very good whereas the borders are somewhat
soft. At f/4 the center reaches excellent levels and the border quality improves greatly.
However, the borders don't reach their peak performance prior of f/8 here.
At 135mm the characteristic is quite similar but the border quality starts
already on a good level at f/2.8. At 200mm the center characteristic remains
intact whereas the borders reside on a very good level throughout the tested
aperture range.
The tested sample produced some strange artifacts - sharp edged halos - in some situations. According to Pentax Japan this is a design limitation.
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)
Lateral Chromatic aberrations (color shadows at harsh contrast transitions) are
minimal and not field relevant.
Verdict
The Pentax FA* 80-200mm f/2.8 [IF] ED is a very good large aperture tele zoom
lens. The resolution figures are generally excellent in the center whereas you
need to stop down somewhat to reach the maximum quality at the borders (80mm and
135mm). Both distortions and CAs are negligible in field conditions. The vignetting
could be a little better at 200mm @ f/2.8 but it's well controlled otherwise.
Typical for a professional grade lens the build quality is excellent.
| Optical Quality: |  |
| Mechanical Quality: |  |
| Price/Performance: | discontinued |
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