Sigma AF 100-300mm f/4 EX DG HSM APO (Nikon) - Review / Test Report - Analysis
Lens Reviews - Nikon / Nikkor (APS-C)
Wednesday, 13 February 2008 11:43

Distortion

Distortion is exceptionally well controlled with this lens. The Sigma produces only marginal barrel distortion at 100mm (0.1%) and very slight pincushion distortion (0.4%) at 300mm.

Move the mouse cursor over the focal length text marks below to observe the respective distortion
100mm 200mm 300mm

Vignetting

Typical for most full format tele lenses the Sigma produces only a marginal degree of vignetting on APS-C type DSLRs. The issue remains below 0.4EV at all focal length even at wide open aperture. The situation remains as good when using the lens combined with a Sigma AF 1.4x converter.

MTF (resolution)

The Sigma AF 100-300mm f/4 EX DG HSM APO delivered excellent resolution figures in the MTF lab matching the best zoom lenses in its range as well as many fix-focal length lenses. At 100mm the Sigma performed about as good as it gets here with an extremely high center performance and only marginally worse borders. Following the zoom range towards the longer end there's a slight decrease in resolution. However, even at 300mm the center resolution remains excellent accompanied by very good borders straight from f/4 all the way up to f/11.
Combined with the Sigma AF 1.4x EX DG converter there's a drop in performance in the center but more so towards at the borders. However, the results remain generally on a very good level although it may be advisable to stop down a little here for an extra kick in terms of contrast.

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)

Lateral CAs (color shadows at harsh contrast transitions) are very well controlled in the native 100-300mm range. The average CA pixel width at the borders varies between extremely low ~0.2px (100mm) and ~0.8px (@ 300mm). The situation deteriorates when adding the AF 1.4x EX DG converter resulting in more noticeable CA pixel widths of around 1.1px.

Bokeh

Regarding its relatively moderate max. aperture (f/4) the Sigma may not be the most interesting candidate for an analysis of the bokeh (the quality of the out-of-focus blur) but if your subject is close enough the lens can render these image parts quite nicely thanks to a smooth and uniform blur and decent, circular out-of-focus highlights (at f/4). At f/5.6 highlights start to show hints of the aperture blade edges though.

You can download the full-size sample images here:




© by photozone.de