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Canon EF 70-200mm f/4 USM L IS - Review / Test Report - Analysis |
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Lens Reviews -
Canon EOS (APS-C)
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Page 2 of 3
Distortion
The level of distortion is very low for a zoom lens with a minor degree of barrel distortion
at 70mm changing to minor pincushion distortion at 135mm and 200mm.
70mm:
135mm:
200mm:
The chart above has a real-world size of about 120x80cm.
Vignetting
Vignetting is very well controlled with the lens. At 70mm and 135mm vignetting is quite already
negligible at f/4. At 200mm there's slightly more vignetting at f/4 (~0.5EV) - usually nothing
to worry about but in extreme situation you may prefer to stop down by a half f-stop to eliminate
the remaining artifacts.
MTF (resolution)
The Canon EF 70-200mm f/4 USM L IS is the very best zoom lens tested to date in Canon mount.
The resolution figures (center/border) at all focal length and all tested aperture settings are nothing
short of stunning and also as good as the best fix-focals in this range. At f/11 there´s the
usual decline in quality due to diffraction - this is a physical limit. Truly remarkable.
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
The lens also showed an excellent behavior regarding lateral chromatic aberrations (color
shadows at harsh light transitions) peaking around 0.6 pixels on the average at the image
borders. This is nothing to worry about by most standards.
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