Diffraction blur with the R5 and four prime lenses

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theninth Regular Member • Posts: 266
Diffraction blur with the R5 and four prime lenses


I just did a test of sharpness and the impact of diffraction blur, which I wanted to share here.

I used four lenses: EF 35 F1.4L (I), RF 50 F1.2L, RF 85 F1.2L and EF 135 F2.0L. All photos were done with an R5, from a tripod, with a cable trigger, electronic shutter, ISO 100 and were then scaled up to 300 %.

It is interesting to see how each lens has its own sweet spot when it comes to sharpness, depending on how well other optical aberrations are corrected at the wider apertures. For the RF 50 F1.2L and the RF 85 F1.2L it seems the sweet spot is already somewhere at F2.8, because other aberrations are well under control at that point, and diffraction blur starts to weigh in. For the other two lenses the sweet spot seems to be at F5.6 and F8.0, because till then the other aberrations outweigh the diffraction blur.

But have a look yourself, here are my results:

And here the whole scene for each lens, so you can see how the test setup looked like:

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 theninth's gear list:theninth's gear list
Fujifilm X100T Canon EOS R5 Canon EF 35mm F1.4L USM Canon EF 135mm F2L USM Canon RF 50mm F1.2L USM +2 more
Canon EF 135mm F2L USM Canon EF 35mm F1.4L USM Canon EOS R5 Canon RF 50mm F1.2L USM Canon RF 85mm F1.2L USM
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