Sigma 100-400 soft on the edges?

Started Sep 1, 2020 | Discussions thread
olstrup Veteran Member • Posts: 4,086
Re: Sigma 100-400 soft on the edges?
4

I have been through many of the replies in this thread, though not them all. If I repeat something already said, I apologize.

The OP has tested his lens with test cards at (presumably) a distance close to the near limit). However, lenses are not necessarily perfectly corrected at all distances. Often compromises must be made, not the least with zoom lenses. If I was a lens designer, with a 100-400mm lens, I would tend to prioritize the sharpness across the field at some distance over the sharpness at close to minimum focusing distance. That may be the explanation that in this thread, the OP says that his lens is a bit corner soft (at close focusing distance) while others show examples shot at close to infinity which exhibit no such corner softness.

Personally, I have never tested new lenses with test cards at close distances for the reason mentioned. I prefer to "test" my lenses in real life situation, typical for the way I intend to use the lens. And as I said, I would use a 100-400mm lens for mostly longer distances. The "Gletscherbruch test" is well suited for this.

https://blog.kasson.com/lens-screening-testing/whats-wrong-with-conventional-lens-screening/

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"Sharpness is a bourgeois concept." (Henri Cartier-Bresson)

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