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Tamron 18-200mm chromatic aberration and purple fringing, tested with Nikon D2X
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To measure purple fringing caused
by lens chromatic aberrations and sensor blooming, we photographed a test
chart, left, with areas of very high contrast. We tested each lens at its
widest and longest focal lengths with the aperture wide open using a Nikon
D2X in Aperture Priority mode. The crops are taken from the upper left corner
of the chart and presented here at 100%. The three lenses performed roughly the same in this test throughout their focal lengths, although the Nikkor 18-200mm zoomed-in to 200mm sports fractionally less fringing. Note the Nikkor lens also has a faster maximum aperture at 200mm of f5.6 compared to the f6.3 of its rivals. |
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Tamron AF18-200mm F3.5-6.3 XR Di-II LD IF
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Nikkor AF-S DX VR 18-200mm 3.5-5.6G IF-ED
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Sigma 18-200mm F3.5-6.3 DC
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18-200mm at 18mm f3.5
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18-200mm at 18mm f3.5
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18-200mm at 18mm f3.5
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18-200mm at 200mm f6.3
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18-200mm at 200mm f5.6
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18-200mm at 200mm f6.3
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Tamron 18-200mm macro, tested with Nikon D2X
| To measure macro performance we photographed a chart using settings
which delivered the maximum possible reproduction. The dark lines are 10mm
apart. Each lens was tested with the Nikon D2X at f8 in Aperture Priority
mode. Tamron, Nikon and Sigma quote closest focusing distances of 45, 50 and 45cm respectively, but by experimenting with different focal lengths and positions, we achieved the maximum reproductions at closer distances. As can be seen below, the Tamron and Sigma lenses were able to deliver greater overall reproduction than the Nikkor model. |
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Tamron AF18-200mm F3.5-6.3 XR Di-II LD IF
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Nikkor AF-S DX VR 18-200mm 3.5-5.6G IF-ED
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Sigma 18-200mm F3.5-6.3 DC
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| 18-200mm at 200mm f8 Max area of 78x52mm |
18-200mm at 170mm f8 Max area of 104x70mm |
18-200mm at 200mm f8 Max area of 78x52mm |
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