Ok, i'm going to update the bug report #99 that fe50 filed. I can't quite read/understand the german forums, but I somewhat see what CHDK is doing in the SD750.
It's somehow ignoring whatever shutter speed the first shot is... instead it's starting with 1" ... from there, it does the normal +1, -1, +2, -2, ...
So, in my trials, I get:
if Tv is 2 +/-
1/8, 4", 1/4, 15", 1/15 ...
0 +1 -1 +2 -2
if Tv is 1/3 +/-
1/8, 1"3, 0"8, 1"6, 0"6, 2", 0"5, 2"5, 0"4, 3"2, 0"3, 4", 1/4, 5", 1/5, 6", 1/6, 8"
0 +1 -1 +2 -2 +3 -3 +4 -4 +5 -5 +6 -6 +7 -7 +8 -8 +9
Help says that +EV should make image brighter... but it seems reverse ...
if Tv is 1/3 -
1/10, 1"3, 1"6, 2", 2"5, 3"2, 4"
if Tv is 1/3 +
1/8, 0"8, 0"6, 0"5, 0"4, 0"3, 1/4, 1/5, 1/6, 1/8, 1/10, 1/13, 1/15, 1/20, 1/25, 1/30, 1/40
I'm glad I found this bug report... i've been pulling my hair out!
/sylikc
