Canon 100-400mm f/4.5-5.6 USM IS II

Started Jul 2, 2019 | Discussions thread
Marquee Regular Member • Posts: 329
Re: Canon 100-400mm f/4.5-5.6 USM IS II

A possible cause of your progressive softness of results could be a lens element de-centering issue - certainly both my 70-200 zooms have suffered from this and softness has appeared particularly on one side of the frame. They both had to go to Canon for optical alignment and were great after that. Dust on internal elements is a fact of life with the 100-400II due to the amount of air displaced with the zoom movements. Dust on internal elements will not typically affect image quality at all, and might look bad but we should resist the temptation to fret about it. A crack on an internal element suggests the lens maybe got a knock at some point and an internal element may be out of alignment. In the UK Canon charge a flat fee for different classes of lenses for a typical optical bench alignment. For a 100-400II I would imagine this is around £200

Mark

 Marquee's gear list:Marquee's gear list
Canon EOS 5D Mark IV Canon EF 100mm f/2.0 USM Canon Extender EF 1.4x II Sigma 50mm F2.8 EX DG Macro Canon TS-E 24mm f/3.5L II +4 more
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