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