Can someone please explain exposure compensation...

[SabrinaO]

...and flash compensation? I was fiddling with them today but I really don't get it... when is it good to use? I really need it dumbed down... Thank you!

 

[Robin Usagani]

EC and FEC are used if you use automatic / semi automatic setting

EC: Lets say you use aperture priority. The camera set the exposure to +-0 (depending on your metering mode). You can tell the camera to always go +1/3, +1, -1, or whatever from the automated value.

FEC: is the same thing if you use e-ttl. You tell the flash to go stronger or weaker from the automated value

If you use manual then there is no such thing as EC and FEC. You just manually set everything.

 

[SabrinaO]

Oh ok! I get it now. I shoot manual 100% of the time and I was saying to myself... What is the point of this? Lol. Thanks for your help!

 

[KenC]

Check your shots after you take them. If your camera shows overexposure by making overexposed areas of the image flash, or by some other means, then you will know if parts of the image are overexposed. Otherwise, you can check the histogram of the image on your camera (the manual should tell you how) and see if a lot of the graph is bunched along the right side, which indicates overexposure. To correct overexposure, you would re-take the shot with an EC of -1, give or take, and see what you get. You can do it by trial and error until you get a feel for what to expect. The opposite problem, underexposure, would be indicated by the histogram mostly being to the left (or the image just looks way too dark), in which case you would try EC of +1 or so. Read a book on exposure (a lot of people on here recommend Understanding Exposure by Peterson(?)) and you will begin to understand what kinds of situations are likely to be problematic and what to do about them.

 

[ann]

Because in manual mode we do it the old fashion way ; by hand

 

[Robin Usagani]

Its all about the metering mode. If you dont understand fully what each metering mode does, then EC & FEC will probably hurt you more than help you.

 

[clanthar]

This note is based on an assumption:

You're using the light meter that's built into your camera.

Light meters come in two basic varieties. They can either measure the light intensity bouncing back from the subject or they can measure the light directly as it falls on the subject. The first of these (reflected light meter) is what's built into a modern camera. The second of these (incident meter) is typically a hand meter: Sekonic

If you meter the incident light then the reflective characteristics of the subject do not affect the calculation. The meter reading will always be 100% accurate. If you meter the light bouncing back from the subject then the reflective characteristics of the subject become part of the calculation. The meter in your camera does not know if you are photographing freshly fallen snow or a coal pile. As such the meter in your camera is programed to assume an average rate of reflectance. Right now you'll see lots of posts here where people are suggesting an exposure adjustment for snow photos. The camera meter assumes snow is a middle grey tone (the average it's programmed for). The camera meter then get's the exposure for snow wrong.

The perfect accuracy of an incident meter is nice, but using an incident meter is often impractical if not impossible. So we use the reflected light meters in our cameras which will always make errors when the subject deviates from average. We see that deviation and we compensate using the camera's exposure compensation feature.

In full manual you would likewise compensate by not zeroing the meter when you know the meter will be wrong.

Joe