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Lens review

Tamron AF 18-250 mm f/3.5-6.3 Di II LD Aspherical (IF)

21 August 2009
Szymon Starczewski

6. Distortion


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As it is common with superzoom wide-angle lens, where the zoom multiple value is more than ten, the distortion is quite difficult to correct. At the shortest focal length we always get a pronounced barrel distortion, which quickly transforms into a noticeable “pincushion”. Typically, the 18-200 mm class lenses at 18 mm have distortion of about –5%, which changes sign at longer focal lengths and reaches 1.5 –2.0 %. The best result in this category belongs to the Sigma 18-200 mm OS, which, at 18 mm,reached the level of –4.4%.

The Tamron 18-250 mm has typical results here. At 18 mm we get a very pronounced pincushion distortion, which level we measured as – 5.29%. The aberration diminishes quickly with the focal length increase, reaching zero near 28 mm, then it changes sign and at 35 mm it reaches a small value of 0.35%. Fortunately, the distortion never exceeds the level of 1.5% at longer focal lengths. At 50 mm its value is 1.34%, at 120 mm – 1.30% and finally at 250 mm it decreases to 1.08%.


Tamron AF 18-250 mm f/3.5-6.3 Di II LD Aspherical (IF) - Distortion

Tamron AF 18-250 mm f/3.5-6.3 Di II LD Aspherical (IF) - Distortion

Tamron AF 18-250 mm f/3.5-6.3 Di II LD Aspherical (IF) - Distortion

Tamron AF 18-250 mm f/3.5-6.3 Di II LD Aspherical (IF) - Distortion