Why are M-mount lenses so lightweight?

Started 1 month ago | Discussions thread
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Steven Seven
Steven Seven Forum Member • Posts: 79
Why are M-mount lenses so lightweight?

After years of shooting primarily with Canon EF-mount SLRs, I recently discovered the manual-focus lenses for the M-mount and I am blow away by how compact they are.

Some 50mm examples (M-mount lenses in italic):

  • Voightlander 50mm f/1.2 : 344g
  • Canon EF 50mm f/1.2L: 580g
  • Sigma 50mm f/1.4 DG: 815g

Let's look at 35mm:

  • Leica Summilux 35mm f/1.4: 320g
  • Voightlander Nokton Classic 35mm f/1.4 MC: 189g !!!
  • Canon 35mm f/1.4L: 760g
  • Sigma 35mm f/1.4 DG: 665g

The trend continues with Zeiss lenses - they are also lightweight and gets somewhat absurd with newer FF lenses for mirrorless cameras (absurd because one of the touted benefits of mirrorless is reduced weight).

Obviously, there's some "weight tax" for adding focusing motors, but I find it hard to believe that AF is that heavy. I also own some of these lenses, and Voightlander 50mm f/1.2 at 344g is not worse optically than my much heavier Canon L. And the 35mm f/1.4 Voightlander at mere 189 gramms, while not clinically perfect, is delightful and perfectly usable wide-open! What does Canon add here at x4 the weight??

I despise lenses above 300g but the numbers above suggest that to escape the pain I have to ditch AF and spend on a Leica body (Sony sensors don't play nice with M-glass via an adapter).

If we have optical engineers here? Why are things getting worse? What's going on?

Thank you.

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