Sigma AF 70-200mm f/2.8 EX DG HSM APO macro (Nikon) - Review / Test Report - Analysis
Lens Reviews - Nikon / Nikkor (APS-C)

Distortion

The 70-200mm EX has a very moderate 3x zoom ratio and the level of distortion is quite low accordingly. At 70mm there's a moderate degree of barrel distortion (0.7%) changing to moderate pincushion distortion (0.7%) at the long end of the zoom range. This is usually not field-relevant.

Move the mouse cursor over the focal length text marks below to observe the respective distortion
70mm 135mm 200mm

The chart above has a real-world size of about 120x80cm.

Vignetting

The 70-200mm EX is a full format lens which enjoy a sweet spot advantage when used on an APS-C DSLR. At 70mm and 135mm the vignetting is negligible even at f/2.8. At 200mm at f/2.8 it is a little more pronounced but still not overly field relevant. If needed stopping down a little solves the problem completely.

MTF (resolution)

The Sigma was able to produce very decent resolution figures in the lab. At 70mm the center resolution is on a very good level followed by good to very good borders. At f/4 and f/5.6 there's a boost in quality which peaks in an excellent center to border performance. This characteristic remains roughly intact at 135mm. At 200mm there's a slight decrease in center performance whereas the borders are already on a very good level straight from f/2.8.

Below is a simplified summary of the formal findings. The chart shows line widths per picture height (LW/PH) which can be taken as a measure for sharpness. If you want to know more about the MTF50 figures you may check out the corresponding Imatest Explanations

Chromatic Aberrations (CAs)

Chromatic aberrations (color shadows at harsh contrast transitions) are generally well controlled with a peak of ~1.1px on the average at the image borders at 135mm and 200mm.




© by photozone.de