basic question about understanding exposure

[bballboy30]

When the camera is metering off a light background, does it makes the exposure darker so that the subject is exposed correctly? If so, if your subject is small and dark you should adjust the exposure to make it lighter. I am sure this question has an easy answer, but exposure is very confusing to me. Thanks for bearing with me.

Alex

[tim]

It depends on the camera and on the metering mode. The answer to your first question will most likely be yes, assuming evaluative metering. For this situation you could use a fill in flash, partial metering (20D), spot metering (1D), or guess the correct exposure compensation value to use.

[J Rabin]

When the camera is metering off a light background, does it makes the exposure darker so that the subject is exposed correctly? Alex

No, the backlight does its level best to correctly fool the sophisticated in-camera meter, making the exposure darker so foreground subject is incorrectly under exposed (haha). You need to search for good web tutorials on "exposure." There are legions. Lke this Forum's own Scott:
http://photography-on-the.net/forum/showthread.php?t=64504
or
http://www.photozone.de/4Technique/index.html
http://emedia.leeward.hawaii.edu/frary/elan7e4.htm
http://photonotes.org/articles/eos-flash/
Many fun books in the stores, like Bryan Peterson's 2n ed. Understanding Exposure.
The solution NOT using exposure compensation, but metering the dominant background and using fill flash in daylight. Canon's flash algorithms automatically reduce the foreground flash in bright light by about 2 full stops. Or holding a fabric reflector to bounce light back onto foreground subject. Here is a high contrast background shot I did today in a greenhouse using radioactive carbon14 to test how golf course grass recovers from drought.
http://postit.rutgers.edu/uploads/5218%20M%20DeCosta%20Turf%2Ejpg
Enjoy. J

[PhotosGuy]

Alex, have you seen the "Gray Card" threads here?
http://photography-on-the.net/forum/showthread.php?t=52418

[bballboy30]

Thanks everyone for all the replies. It looks like I have a lot of research to do.

Thanks again.
Alex

[J Rabin]

bballboy30.
Since my photography is usually in odd contrasty settings, I'll give you one more before we bury this thread. An old photojournalist taught me:
"Expose the background with shutter speed (or with digital a combination of shutter speed and/or ISO) and the foreground with f/stop (or combination of f/stop and fill flash)."
Chew on that and do experiments with the camera, like popular "teddy bear" exposures on Nikonians web site. The Canon reflective meter probably has a database of 10s of thousands of "exposures" built into its memory chips to compare any "AE" metered setting, and it will still be fooled every day! Here is a typical PJ example:

http://postit.rutgers.edu/uploads/NC%20Ext%20Food%20Safety%20Prog%2Ejpg

Here I had to meter for the LCD projection screen to not over expose it (think backlight), while holding a flash off camera to properly expose the speaker against another backlight to his left. Digital makes this easier for sure, but I use the 20D in manual exposure mode 70%+ of the time in the setting you described. Enjoy. J.

[PhotosGuy]

bballboy30 I find it easier to think of that as "Read the overall exposure, set it on "M", then set the flash fill to about 1/2 that."
If I'm using a 2nd flash to separate someone from the background, I'd set that flash at a higher level.
See: http://photography-on-the.net/forum/showthread.php?t=66358