100mm F2 vs 85mm 1.8 or 1.4..which one has more "bokeh"

Discussion in 'Open Discussion' started by shaolin95, Jul 22, 2016.

  1. shaolin95

    shaolin95 TalkEmount Top Veteran

    942
    Jul 3, 2013
    I thought I had this figured out a long time ago but checking some calculators and bokek simulators online, I got confused.
    Does 100mm F2 have a smaller DOF than 85mm 1.8 if framing the subject the same way..ie a full body shot? How about 85mm 1.4 and 135mm F2?
    I feel kind of silly now :D

    Thanks!
     
  2. MAubrey

    MAubrey TalkEmount Top Veteran

    A 100mm f/2 and 85mm f/1.8 would be about the same. A 135mm f/2 would be closer (but not quite there) to an 85mm f/1.2.

    The easiest way to compare the quantity of blur is to simply divide the FL by the f-number. 100mm f/2 = 50, 85mm f/1.8 = 47.22. For a given subject magnification, the same size physical aperture will always give you the same amount of blur.*

    *a shorter FL with a larger f-number can still give more blur if the distance between the subject and the background is small.
     
    • Informative Informative x 3
    • Like Like x 1