Exposure values (EV) - What does it actually do?

[herc182]

Ok, so I know OF it but dont know what it actually does. Say for example I set it at +1 ev what is it acually doing. It overexposes/underexposes depending on what side of 0 you go. If it underexposes the shutter stays open for less time. if it overxposes it leaves the shutter open for longer. So why not just change the shutter speed?

I dont understand :( going onto google but would like to know your thoughts and how you use exposure.

[VTEC_EATER]

If you are in full manual, then playing with exposure compensation is the same as changing the shutter speed.

But what if you are in Shutter priority? Do you risk changing your shutter speed and possibly missing the effect of slow shutter speeds that you were planning on using for the shot? No, you wouldn't want to do that. You adjust the exposure compensation, and the camera will change the lens aperture ( I believe... I dont think it would change ISO, thats too drastic). Unless you are at full open on your lens, there shouldnt be any problems. But if you are, you can not get more exposure without changing the shutter speed or changing the ISO, the latter of which will have less fine tuning.

If you are in Aperture priority, the metering of the camera will set the shutter, but depending on reflections or the other surfaces around your subject, the metering could be off, hence the reason for exposure compensation.

[tcadwall]

A couple of light reads...

http://www.dpreview.com/learn/?/key=exposure_compensation
http://www.photoxels.com/tutorial-exposure-compensation.html

[herc182]

thank you for your replies. I apologise for not getting back to you sooner. I am now in the know with EV! sort of cleared me up!

thanks