|
Canon EF 55-200mm f/4.5-5.6 USM II - Review / Lab Test Report - Analysis |
|
Lens Reviews -
Canon EOS (APS-C)
|
|
Page 2 of 2
Distortion
The level of distortion is about average for a tele zoom lens with a moderate degree
of barrel distortion at 55mm changing to slight pincushion distortion at 135mm and 200mm.
55mm:
135mm:
200mm:
The chart above has a real-world size of about 120x80cm.
Vignetting
Vignetting is very well controlled with the lens - not really a surprise for a full format
lens used on an APS-C DSLR. At 55mm @ f/4.5 vignetting is sightly more pronounced but
usually not field relevant. At other aperture settings or longer focal lengths vignetting
is negligible.
MTF (resolution)
The Canon EF 55-200mm f/4.5-5.6 USM delivered surprisingly decent resolution figures.
At 55mm the results are excellent and still generally very good at 135mm and 200mm.
However, this is really only part of the story because the variation in quality was
quite extreme with large soft image portions towards the borders. The MTF charts below
don´t quite tell the complete story here. The contrast level is very low at 200mm @ f/5.6
but improves a bit at f/8 - without reaching Canon L or fix-focal lens levels naturally.
Samples:
100% crop (bottom center) at 55mm f/8
100% crop (bottom center) at 200mm f/8
Technically the center and border MTFs are measured at edge transitions. As you
may see in the samples below the lens performs fine here:
100% center crop @ 200mm f/5.6
100% border crop @ 200mm f/5.6
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 shows quite pronounced CAs (color
shadows at harsh light transitions) peaking around 1 pixels on the average at the image
borders. However, again this is only a very rough guidance. The CA distribution is not
symmetrical with local CA peaking beyond 2px.
Verdict
The Canon EF 55-200mm f/4.5-5.6 USM II is a lens with "potential". Unfortunately it is wasted
due to a very poor mechanical quality based on very cheap plastics.
The lens has been simplified to a degree where even the focus ring has been abandoned. Thanks to the
unambiguous aperture and focal length range the optical quality of the lens is very good or at least
it could be. The formal results are fine if not impressive for such a lens but they vary extremely
across the frame - probably also a side effect of the low build quality standards. If Canon had put
the optics into a decent lens body it would have been an interesting budget lens but in its current
incarnation the Canon EF 55-200mm f/4.5-5.6 USM II cannot be recommended.
|
