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Canon EF 100mm f/2.8 USM macro - Review / Test Report - Analysis |
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Lens Reviews -
Canon EOS (APS-C)
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Page 2 of 3
Distortion
As expected for a fix-focal lens and especially for a macro lens the level of distortion is absolutely
negligible.
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 exhibits moderate vignetting
at f/2.8 which disappears from f/4 & up. Expect more vignetting on 1.3x or full frame cameras.
MTF (resolution)
The lens was tested twice but only to obtain data beyond f/8 which was missing in the first review.
The MTF differences between the two tested samples are insignificant.
Typical for most macro lenses the EF 100mm f/2.8 USM macro performed highly impressive in the lab.
The lens is already very good in the center at wide-open aperture with marginally worse corners.
The lens reaches its peak performance at f/5.6. You shouldn't stop down beyond f/16 due to the limiting
effects of light diffraction.
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
The quality of the bokeh (the fore-/background blur at large apertures) is smooth. You need to
be a little careful regarding lens flare with this lens - using the hood is a good idea especially
with streaking light.
Chromatic Aberrations (CAs)
Similar to most other fix-focal lenses chromatic aberrations (color shadows at harsh contrast transitions) are
very low and nothing to worry about.
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