LensTip.com

Lens review

Canon EF 70-200 mm f/4L IS USM

9 October 2007
Arkadiusz Olech

7. Coma and astigmatism



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The lens corrects the coma very well. It is very hard to notice the coma’s influence on the diode picture at 135-200 mm. It is visible at 70 mm but the effect is very modest. The usage of the converter doesn’t result in any defect boom.

Canon EF 70-200 mm f/4L IS USM - Coma and astigmatism


The average astigmatism value for the 70-200 f/4L IS reached 5.7%. The defect was less noticeable as the focal length increased from 9% at 70 mm to 3.2% at 200 mm. When we add other optical combinations using the converter, the astigmatism increased to 5%. The overall outcome in this category is very good with a slight weakness at the 70 mm focal length.