I recently bought a Canon FD 300mm f/4L lens (and have been quite pleased with the results. This is the older breechlock mechanism as opposed to the New FD mount. I was wondering what the differences were between the New and Old version. i.e., is the optical formula the same, or is the only difference in the mount? Thanks.
FD 300mm f/4.0 L - "Old" vs. "New
in Canon FD Mount
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