11th August 2003, 08:59 PM
Are Exposure Compensation and Flash Compensation Independent ?
I was wondering if exposure compensation and flash compensation are independent? As in .... if u adjust the exp. comp. to be -1 stop and the flash compensation to be +1, would the overall picture be underexposed by 1 stop because the camera is instructed to be underexposed, and even though flash ev is +1, that only changes the ratio of flash to background light ? Not sure if u understand what I mean ...
Or if I do a +2 on flash compensation and nothing on exp. comp. , the overall picture will be correctly exposed ? Just that more flash is used with a ..perhaps smaller aperture to counter the larger flash output ?
I sound confusing, but I was facing these dilemma just on my last roll.
Those who can comprehend, pls advise. Many thanks. I do have the wierdest questions eh ? keke...sorry.
12th August 2003, 09:07 AM
If the flash is not at its maximum output and the camera is not at its maximum flash sync speed;
Originally Posted by marcwang
A change in Exposure compensation will be independent of Flash exp comp.
Else if the flash is at the maximum output and the camera is already at the maximum flash synchro speed (eg 1/125s);
Since the flash sync speed cannot be increase further, an exposure compensation to decrease exposure can only reduce the aperture size. Thus if the flash output cannot be increase any more, a reduction in aperture size will cause the flash exposure to reduce as well.
12th August 2003, 01:11 PM
To answer your question, you must first understand how both works...
Expo comp works best only in Program, Aperature or Shuttle prioty mode. Why is this so, when in these mode, your cam meter will make any picture to become 18% gray depend on your metering mode. If you want to change the exposure, only way is use expo comp cos if you change the setting in lets say aperature prioty, the shuttle will change according to get 18% gray.
For example if you're shooting bright snow, cam will think pic is too bright, thus it'll close down it's setting resulting in overall pic becoming underexpose. Thus you'll need to use expo comp to compensate the exopsure. Normally in this case, we key in a + value depending on what tone I want the snow to be....
Flash compensation works more or less the same but it vary the flash output. Thus if you shoot a subject at night and you + the flash, your subject will recieve more light and become brighter. But if you + your EV, you subject and background will become brighter. So it all boils down to how you want your resulting picture to turn out....
Oh ya, it also depends on what flash mode you use. If it's TTL then most likely it's dependent. And what jasonpgc says applies too....