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Canon EF-S 55-250mm f/4-5.6 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 EF-S 55-250mm produces a moderate degree of barrel distortion at 55mm (~1.1%) and slight
pincushion distortion beyond (~0.7%).
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Move the mouse cursor over the focal length text marks below to observe the respective distortions
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| 55mm |
135mm |
200mm |
250mm |
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The chart above has a real-world size of about 120x80cm.
Vignetting
Being a dedicated APS-C lens the Canon EF-S 55-250mm f/4.5-5.6 IS produces comparatively high
vignetting close to 1EV at "large" aperture settings. This may be disturbing at times. Beyond
the max. aperture it isn't really a problem anymore.
MTF (resolution)
The lens produced pretty impressive resolution figures in the MTF lab. The resolution
characteristic is generally very good across the image frame. Unsurprisingly the lens
performs best at 55mm but there's only a slight deterioration towards the long end of the
zoom range - surely the benefit of the large UD element in the front lens group.
Subjectively the contrast level suffers somewhat at longer focal lengths though (not visible
in the graphs below).
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)
The level of lateral chromatic aberrations (color shadows at harsh contrast transition) is very
low and usually not field relevant at less than 0.5px on the average at the image borders.
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