More 100-400 'Halo' tests

Started 3 months ago | Discussions thread
fft2000 Contributing Member • Posts: 883
Re: More 100-400 'Halo' tests
3

Setups without IS have a fixed path for the light through the lens. So as long as the lens isn't decentered it should have equal fringing for points with the same distance to the center.

IBIS floats the sensor behind the lens, so it uses the projected image(s) with some offset from the centered setup. Usually when you go from center to corner you will see an increase in CA/fringing.

lens-IS is similar to IBIS in this regard: it has an additional lens element that can shift freely perpendicular to the light path (in contrast to the fixed other lenses), in order to project the framed scene in the same place. It therefor also forces the light to take a different route through the lens using portions that have more CA/fringing.

So I think what you are seeing is just enhanced fringing. high contrast edges are always susceptible for fringing. I remember that I once thought my PL 100-400 was badly decentered as I had extreme fringing in one corner and none in the other. A test with IS off on a tripod showed equal fringing in both corners, so the difference was caused by the IS.

(sorry for my bad English, I hope you get what I mean).

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