Comments on: Operator Error, a Great AF System — but …, a large Crop, and not too bad an image. And a variable aperture zoom lens tip! https://www.birdsasart-blog.com/baa/2020/12/13/operator-error-a-great-af-system-but-a-large-crop-and-not-too-bad-an-image-and-a-variable-aperture-zoom-lens-tip/ The blog of bird photographer Arthur Morris Fri, 07 Mar 2025 15:43:19 +0000 hourly 1 https://wordpress.org/?v=6.8 By: Arthur Morris/BIRDS AS ART https://www.birdsasart-blog.com/baa/2020/12/13/operator-error-a-great-af-system-but-a-large-crop-and-not-too-bad-an-image-and-a-variable-aperture-zoom-lens-tip/comment-page-1/#comment-1806878 Mon, 14 Dec 2020 21:56:20 +0000 http://www.birdsasart-blog.com/?p=70607#comment-1806878 In reply to Geoff.

Thanks again, Geoff. You are a treasure. I will give it a try.

with love, artie

]]> By: Joel Eade https://www.birdsasart-blog.com/baa/2020/12/13/operator-error-a-great-af-system-but-a-large-crop-and-not-too-bad-an-image-and-a-variable-aperture-zoom-lens-tip/comment-page-1/#comment-1806858 Mon, 14 Dec 2020 13:58:05 +0000 http://www.birdsasart-blog.com/?p=70607#comment-1806858 In reply to Sanjeed Quazi.

I have used the following EF lenses with the R5 and the RF to EF adapter. I have noticed absolutely no degradation in their normal performance in terms of focusing and image quality.

– 600mm f/4L IS USM II alone, with the 1.4 TC II and also the 2.0 TC III (did not try stacking the extenders)

-16-35mm f/2.8L III

-24-70mm f/2.8 II

-100-400mm II

-70-200mm f/2.8L II

All of these function with no issues that I can discern …. the full array of focus points are available and focusing is fast as well as accurate. I would not hesitate to recommend using the adapter with any of the lenses listed above.

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