function set_ETTR() local histo={} local total = 0 histo,total=get_live_histo() total = 0 local max = #histo local start = max-hlw for i = start,(max-1),1 do total = total + histo[i] end -- get the total count in the requested quartiles press("shoot_half") repeat sleep(10) until get_shooting() s = get_tv96() set_user_tv96(s) release("shoot_half") repeat sleep(10) until (not get_shooting()) if total > 0 then -- overexposed i = 0 repeat wheel_right() -- move 1 stop, but note camera must be set to 1/3 stops wheel_right() wheel_right() histo,total=get_live_histo() total = 0 for i = start,(max-1),1 do total = total + histo[i] end until total <= 0 repeat wheel_left() histo,total=get_live_histo() total = 0 for i = start,(max-1),1 do total = total + histo[i] end until total > 0 wheel_right() elseif total <= 0 then -- underexposed i = 0 repeat wheel_left() -- move 1 stop, but note camera must be set to 1/3 stops wheel_left() wheel_left() histo,total=get_live_histo() total = 0 for i = start,(max-1),1 do total = total + histo[i] end until total > 0 repeat wheel_right() histo,total=get_live_histo() total = 0 for i = start,(max-1),1 do total = total + histo[i] end until total <= 0 end returnend
This is experimental and I'm not sure where it will end up; but the RAW EV histogram seems to show some promise (for me at least).
Started by pigeonhill General Discussion and Assistance
Started by pigeonhill General Help and Assistance on using CHDK stable releases