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Canon EF 24mm f/1.4 USM L - Review / Test Report - Analysis |
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Lens Reviews -
Canon EOS (APS-C)
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Page 2 of 3
Distortions
The lens shows slight but still visible barrel distortions.
The chart above has a real-world size of about 120x80cm.
Vignetting
On an APS-C DSLR the EF 24mm f/1.4 USM L enjoys a sweet spot effect here. However,
this doesn't seem to be enough to produce low vignetting at max. aperture.
Admittedly f/1.4 is a rather extreme setting specifically for a wide-angle lens
but the vignetting shouldn't really exceed 1EV on an APS-C camera. At f/2 the
problem is already reduced to a very acceptable degree and from f/2.8 the
issue is negligible.
MTF (resolution)
The EF 24mm f/1.4 USM L showed two different souls in the lab. The center performance
of the lens already good to very good at f/1.4 increasing to superb
resolution figures from f/2.8 onwards where it easily reaches and
probably exceeds the resolution limits of an 8mp sensor.
Unfortunately the borders aren't quite as good. At f/1.4 they
are soft and it requires f/4 to reach very good territory which is relatively
"late". The border quality peaks at f/8.
The resolution characteristic at the borders is slightly disappointing for a fix-focal lens with this price tag.
The resolution chart has been marginally revised to take residual spherical aberrations and field curvature into account.
Below is a simplified summary of the formal MTF findings. The chart shows in line widths
per picture height (LW/PH) which can be taken as a measure for sharpness. If you want to
know more about it you may check out the corresponding
Imatest Explanations.
Chromatic Aberrations (CAs)
CAs (visible as color shadows at harsh contrast transitions) can reach an average CA pixel width
of around 1 pixels at the image borders - an acceptable performance for a wide angle lens but again
a little disappointing for this specific lens.
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