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Lens review

Canon EF-S 10-18 mm f/4.5-5.6 IS STM

15 July 2014
Szymon Starczewski

7. Coma, astigmatism and bokeh

We don’t have any serious reservations concerning the coma correction – the crops, shown below, are the proof the lens performs well here. In fact the Canon EF-S 10-18 mm fares noticeably better than its more expensive 10-22 mm brother.

Canon EF-S 10-18 mm f/4.5-5.6 IS STM - Coma, astigmatism and bokeh


The astigmatism is corrected as well as the coma. The average difference between horizontal and vertical MTF50 function values amounted to 3.5% which we consider a good result.

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Defocused light circles don’t look well, though – you can notice a distinct rim near the edge and in the frame corner the light is spread very unevenly. It is of course a result of high vignetting which will be described in more detail in the next chapter.

Canon EF-S 10-18 mm f/4.5-5.6 IS STM - Coma, astigmatism and bokeh