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Painting Zoom Lenses with a Broad Brush – Roger’s Law of Wide Zoom Relativity

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I’ve been writing peer-reviewed scientific papers for way longer than I’ve been blogging about optics. I value significant numerical information presented with methods that allow reproducibility as much as anybody. But way too many people who can’t define either spurious accuracy or spurious resolution believe (and unfortunately create) nonsense numbers on the internet and repeat them as though they mean something. So […]

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Lens Teardown of the Complicated Sony FE 70-200mm f/2.8 GM OSS: Part I

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A lot of you are aware that we’ve been rather puzzled by the Sony FE 70-200mm f/2.8 GM OSS lens. It didn’t test like we expected it to, which led us to reevaluate our testing methods with outside consultants (we’re now comfortable they are valid, BTW), question the accuracy of different types of autofocus, and search […]

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Things You Didn’t Want to Know About Zoom Lenses

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The intersection (perhaps collision is a better word) of art and science is interesting. The scientist says “your impression is not as important as my facts.” The artists say “my impression is all that matters.” Imaging is that way. The photographer or videographer getting the look he wants from a piece of equipment is all that […]

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MTF Tests for the Sigma BBL: The Big, Beautiful, 85mm Art Lens

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Yes, I know the Sigma 85mm f/1.4 DG HSM Art lens just too big for you; reading the online forums, you’d think it was about the same size and weight and a 600mm f/4 lens. It’s not, of course, although it is a hefty lens at nearly 40 ounces. But that’s just a few ounces more […]

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