Exposure Compensation

[Necroist]

Will using the +ev -ev settings on a camera cause any sort of problems? Like additional grain, bad colour and stuff?

 

[Tweek]

not in general, but yes it may cause some problems if you use it erroneously. Exposure compensation merely makes the camera take the shot at an exposure higher/lower than the metered one. So if the metering is correct, but you -vely compensated by too much, the image will be underexposed. If the film is negative, the developer might push/adjust it for you and it will be grainy.

So in summary, ev compensation only changes the shutter speed or aperture value which results in a different exposure, and any problems that may arise from it will be due to the incorrect use of it.

 

[Necroist]

changes the shutterspeed?!

If all it does is change the shutterspeed, why use it at all?

 

[mpenza]

Originally posted by Necroist
changes the shutterspeed?!

If all it does is change the shutterspeed, why use it at all?

perhaps this article could help:
http://www.shortcourses.com/using/exposure/chapter3.htm

An extract:
You shouldn’t, however, always leave the exposure to the automatic system. Automatic exposure works well in most, but not all, lighting conditions. At times the lighting can fool any automatic exposure system into producing an underexposed (too dark) or overexposed (too light) image. Although you can make adjustments to a poorly exposed image in a photo-editing program, you’ve lost image information in the shadows or highlights that can’t be recovered. You will find it better in some situations to override the automatic exposure system at the time you take the picture.

Typical situations in which you might want to override automatic exposure include interesting and unusual lighting situation. For example, if you want to photograph into the sun, record a colorful sunset, show the brilliance of a snow-covered landscape, or convey the dark moodiness of a forest, you will probably need to adjust exposure, rather than let the camera make exposure settings automatically.

 

[Tweek]

Originally posted by Necroist
changes the shutterspeed?!

If all it does is change the shutterspeed, why use it at all?

exposure is determined by mainly three variables: shutter speed, aperture size and sensitivity of film.

So when you do exposure compensation, the camera will adjust exposure by changing one of these variables. For a film camera, ISO can't be changed so that's left untouched. In shutter priority mode, shutter speed is fixed by user, so camera changes aperture size. In aperture priority mode, the opposite happens, camera changes shutter speed. Try it out on your camera, most cameras refresh the exposure information immediately once you compensate, and you can see the shutter speed/aperture change.

Of course, you can change shutter speed/aperture yourself, by going into full manual mode. That's why in full manual, there is no such thing as exposure compensation.

You can put it this way, exposure compensation is a convenience for users using shutter/aperture priority mode to override the camera's metering, as they do not have to go into full manual mode to do that and count the fstops.

 

[Necroist]

So Apeture Piority and Shutterspeed Piority == forms of exposure compensation? But I was referring to the -ev +ev

 

[mpenza]

Originally posted by Necroist
So Apeture Piority and Shutterspeed Piority == forms of exposure compensation? But I was referring to the -ev +ev

no. when you +ev -ev in any mode = exposure compensation. read the article and you would probably understand a lot more.

 

[Tweek]

Originally posted by Necroist
So Apeture Piority and Shutterspeed Piority == forms of exposure compensation? But I was referring to the -ev +ev

no, maybe I wasn't very clear, what I meant was doing exposure compensation while in shutter/aperture priority mode, and not that shutter/aperture priority modes are exposure compensation.

Read my post above again and see if it makes sense.