Iris F-number 8 31.93131 9 27.67758 10 23.42385 11 19.08646 12 15.40131 13 12.70277 14 10.89002 15 9.630773 16 8.710001 17 7.98091 18 7.372274 19 6.808854 20 6.280682 21 5.805998 22 5.416886 23 5.089967 24 4.806457 25 4.53819 26 4.278139 27 4.021033 28 3.7894 29 3.594503 30 3.43187 31 3.288829 32 3.159458 33 3.036577 34 2.921591 35 2.812321 36 2.708197 37 2.616321 38 2.531278 39 2.44368 40 2.360728 41 2.289606 42 2.230438 43 2.172744 44 2.116655 45 2.064817 46 2.018038 47 1.973099 48 1.930412 49 1.890958 50 1.854834 51 1.818739 52 1.783255 53 1.749807 54 1.719666 55 1.693504 56 1.667763 57 1.641014 58 1.614799 59 1.588721 60 1.564187 61 1.542114 62 1.523184 63 1.505896 64 1.490337 65 1.476271 66 1.462802 67 1.448973 68 1.436443 69 1.426584 70 1.419671 71 1.415865 72 1.413988