1 aspherical, 3 low dispersion, 2 super low dispersion
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The Digital Picture
There are very few lenses as sharp as this one at f/1.4. [...] Having an f/1.4 aperture is extremely desirable. While no 105mm f/1.4 lens is going to rule the bokeh world, the Sigma-self-dubbed "Bokeh Master" does have the ability to create a very strong (and high quality) background blur at its very useful focal length. [..] I experienced some inconsistent AF accuracy on my Canon 5Ds R test camera and while that is an issue, you may not encounter the same.
There’s no question that the extreme size and weight of the 105 ART will be off-putting to many, but those with a little extra arm strength will be rewarded with an exceptional portrait lens. [...] The autofocus works well, the images look fantastic, and the build level is high.