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Tokina AF 17mm f/3.5 AT-X Pro - Review / Lab Test Report - Analysis |
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Lens Reviews -
Canon EOS (APS-C)
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Page 2 of 2
Distortion
Typical for many wide to ultra-wide lenses the Tokina AF 17mm f/3.5 AT-X Pro
exhibits some barrel distortion. The issue is relatively pronounced here at about
1.7% but that's still quite a bit less compared to the Canon standard
zooms in this range (but not better than the ultra-wide zooms).
The chart above has a real-world size of about 120x80cm.
Vignetting
On the EOS 350D with its reduced format (APS-C) the (full format) lens
fully enjoys the sweet spot behavior with vignetting figures that are
already totally negligible at wide-open aperture. Quite an amazing
performance here.
MTF (resolution)
The lens exhibited a quite even performance in the lab with a good to
very-good center and slightly worse borders figures throughout the
tested aperture range. Nothing special but solid.
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)
CAs (color shadows at harsh contrast transitions) are a little on the high side with
an average CA pixel width between 1.27 and 1.46 pixels at the image borders.
Relatively speaking this is in line with the better zoom lenses in this range.
Verdict
The Tokina AF 17mm f/3.5 AT-X Pro proved to be a solid performer during the tests
with no pronounced weaknesses relatively to its lens class. Nonetheless its
resolution performance is matched and sometimes even exceeded by some good quality
zooms so there're a few question marks behind its concept. That said it
remains a good option regarding its moderate price tag.
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