Alley in Pisa, Italy

by Lars Kotthoff

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13
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3answers
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How to test what aperture is actually used?

It seems odd to me that Canon EF 100-400mm f/4.5-5.6L does away with a front element of only about 63 mm, as reported by @jrista - which would be enough for only f/6.3 at 400mm, missing the spec by ...