Just for fun here's a table with theoretical values with two
decimal places and what the camera (EOS 3) shows in parentheses:
full stop +1/3 +1/2 +2/3
1.00 (1.0) 1.12 (1.1) 1.19 (1.2) 1.26 (1.2)*
1.41 (1.4) 1.59 (1.6) 1.68 (1.8)* 1.78 (1.8)
2.00 (2.0) 2.24 (2.2) 2.38 (2.5)* 2.52 (2.5)
2.83 (2.8) 3.17 (3.2) 3.36 (3.5)* 3.56 (3.5)*
4.00 (4.0) 4.49 (4.5) 4.76 (4.5)* 5.04 (5.0)
5.66 (5.6) 6.35 (6.3) 6.73 (6.7) 7.13 (7.1)
8.00 (8.0) 8.98 (9.0) 9.51 (9.5) 10.08 (10)
11.31 (11) 12.70 (13) 13.45 (13) 14.25 (14)
16.00 (16) 17.96 (18) 19.03 (19) 20.16 (20)
22.63 (22) 25.40 (25) 26.91 (27) 28.51 (29)
32.00 (32) 35.92 (36) 38.05 (38) 40.32 (40)
45.25 (45) 50.80 (51) 53.82 (54) 57.02 (57)
64.00 (64) 71.84 (72) 76.11 (76) 80.63 (81)
90.51 (91)
Asterisks indicate where the camera rounds wrong.
In every case the +1/2 has the same value as either
the preceding +1/3 or the following +2/3 value,
and the value is such that it occurs as the
maximum aperture of some lens in Canon's lineup.
In other words, exactly what would be needed to make
every lens display the advertized maximum aperture
with both 1/2 stop and 1/3 stop increments.
Anyone care to bet that Canon is never going to make a lens
with max aperture f/1.1, f/1.6, f/2.2 or f/3.2? :-)
--
Tapani Tarvainen
*
****
*******
***********************************************************
* For list instructions, including unsubscribe, see:
* http://www.a1.nl/phomepag/markerink/eos_list.htm
***********************************************************
