Tag: distortion

Optical Distortion explained

Optical distortion is a serious problem, low-cost or high quality lenses produce distortion. This post explains the origins of these anomalies, how to reduce their results while shooting or using computer programmes.

Aberrations are caused by the shape and the design of a lens. These aberrations lead to optical distortion which does not affect so much some subjects, for example, landscapes. Optical distortion, instead, makes obvious in buildings or in highly geometric structures such as chess boards. The degree of distortion a lens produces does not depend on lens focal length: so we have the same grid pattern from 18mm up to 300mm. However, wide-angle lenses usually originate stronger optical distortion than tele-lenses.

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Canon EF-S 18-135 mm f/3.5-5.6 IS lens review

The Canon EF-S 18-135 mm f/3.5-5.6 IS lens is considered to be an economical choice but with clutched image stabilization and an amazing 7.5x zoom range which is equal to 29-216 on a 35 mm camera is everybody’s pick. The image stabilizer assures sharp shots at shutter speed up to four stops slower than without stabilization. The look of the lens is pretty eye catchy with barrel of the lens made out of texture finished plastic and silver ring besides focus control. The zoom ring can be managed easily because of the broad rubberized grip. Focus execution takes place internally because of which front filter does not rotate while zooming thus making polarizing filters easy.

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