please provide adresses or tutorial how to obtain these for other cameras 
How to obtain address of function, which name exists in firmware? Very simply (example for S3IS)
1. Seach string "GetCCDTemperature":
ROM:FF82D300 CMNMI R4, #0x11C00000 ; Set cond. codes on Op1 + Op2
ROM:FF82D304 LDRVSB R4, [R4,#-0x443] ; Load from Memory
ROM:FF82D308 RSBVC R7, R5, #0x6D ; Rd = Op2 - Op1
ROM:FF82D30C RSBVCS R7, R5, #0x61000000 ; Rd = Op2 - Op1
OMG, this is string, not code! Press 'A' key to convert into string:
ROM:FF82D300 aGetccdtemperature DCB "GetCCDTemperature",0 ; DATA XREF: sub_FF82D244+8Co
if IDA cannot find data reference to string, search it manually (press Alt+B and enter FF82D300)
2. Jump to reference:
ROM:FF82D2D0 DCD aGetccdtemperature ; "GetCCDTemperature"
ROM:FF82D2D4 DCD loc_FF82D368
ROM:FF82D2D8 DCD aGetbatterytemperature ; "GetBatteryTemperature"
ROM:FF82D2DC DCD loc_FF82D37C
Canon's firmware very often includes such lists - first item is name, second - address of function (for service purpose).
So, address of GetCCDTemperature is 0xFF82D368 (loc_FF82D368), address of GetBatteryTemperature is 0xFF82D37C etc.
P.S. Smart IDA scripts can do such things automatically.
