32 responses to “Sigma 85 1.4 Pricing & MTF”

  1. IIRC, 1 stop difference is defined when the difference in the aperture area is 2 times (or 100% bigger in other words).

    Here:

    (1.8 * 1.8 – 1.4 * 1.4 ) / (1.4 * 1.4) = 65.3%

    I’d say the difference is in between 1/2 and 3/4 stops.

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