Sigma A 105 mm f/2.8 DG DN Macro review - Vignetting

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Sigma A 105 mm f/2.8 DG DN Macro

27 November 2020

Maciej Latałło

8. Vignetting

First let's see how the Sigma performs on the smaller APS-C sensor – appropriate thumbnails you can find below.

A7R II, APS-C, f/2.8	A7R II, APS-C, f/4.0

You don't notice almost any problems at this place. Even at the maximum relative aperture vignetting is difficult to notice as it reaches just 18% (-0.58 EV) and then it decreases to a completely imperceptible value of 8% (-0.24 EV) on stopping down the aperture to f/4.0.

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How does the situation look on full frame? Appropriate thumbnails you can find below.

A7R II, FF, f/2.8	A7R II, FF, f/4.0

A7R II, FF, f/5.6	A7R II, FF, f/8.0

Looking at the narrow barrel of the tested lens and truncated circles of light in frame corners from the previous chapter we expected here a lot of problems. However, the Sigma managed to surprise us very nicely. By f/2.8 brightness loss in frame corners amounts to 36% (-1.28 EV). It is a value easy to spot but Sony FE lenses made us used to results of 2-3 EV in this category so, overall, the Sigma doesn't perform so badly. It's worth reminding here that the rival Sony 2.8/90 showed here a level of 53%.

Stopping down the lens to f/4.0 is able to decrease vignetting to 29% (-0.98 EV), and applying the f/5.6 relative aperture makes that aberration drop even further to 24% (-0.81 EV). The decrease of vignetting on stopping down is really steep - our measurements by f/8.0 and f/11.0 showed, respectively, 20% (-0.64 EV) and 14% (-0.44 EV). Only after applying f/16.0 you might get rid of vignetting, with a quite symbolic result of 8% (-0.26 EV).

Sony A7R II, JPEG, f/2.8

Below we present averaged out values of brightness loss shown in concentric circles as you move further away from the frame centre. The numerical value for every image, expressed in percents, shows the area limited from the top and right by 100% and from the bottom by the presented curve. The area indicates how much light overall is lost due to the vignetting effect. Please don’t mix these percentages with the values given at the beginning of the chapter because they aren’t directly connected.

Sigma A 105 mm f/2.8 DG DN Macro - Vignetting