EXPOSURE COMPENSATION

[Jeff Donald]

Can the people who develope my photos override this automated processing system?

Some labs can and some can't.  It depends on the equipment being used and the training of the personnel operating it.  Your question is best directed to the lab you use for processing.

[mebow]

For additional reading try this page

http://www.photozone.de/bindex4.html

good luck. Mike

[Aaron Reynolds]

Andrew,

The light meter in your camera works on the assumption that your subject is neutral mid-tone grey so if you are photographing snow or very white sand for example then the exposure determined by the camera will render it darker than it appears in reality. This is where the photographer must intervene by dialing in an appropriate amount of exposure compensation. This is easier once you are familiar with the idiosyncracies of your camera's light meter. The best way to learn is to shoot a roll of your favourite transparency film on a few different scenes, dialing in varying amounts of exposure compensation and taking detailed notes with a pencil and paper. There are also many great books and resources on the web if you search for the "simplified zone system." Best of luck and welcome to the wonderful world of photography.

[Joe Hardesty]

Andrew,

Don't get hung up thinking about snow and sand--those were only examples. Think about it this way:

Your camera meter is giving you the proper exposure based on the metered area being approximately the same light value as middle gray. If you are shooting general landscapes, flowers, houses, or even light-skinned people, this value is fairly accurate, but in other cases it is not.

If you point it at a white lilly, the camera says "OK, you want the lilly to be middle gray". If you point it at a black dog, the meter says "OK, you want the dog to be gray". In these cases, you have to compensate for the meter's thinking. Light measurements are all about shades of gray and not about color.

If you want to know what middle gray looks like, go into photoshop and fill a new document with a color that is R=192 G=192 B=192. That is middle gray.

Now take some of your photos and convert them to grayscale images and you should be able to see how the camera views light values. Look for areas of the photo that are like the 192-192-192 document you made and you should see that they are in the general center of the exposure.

This is one of the most important concepts in photography. I suggest you do some experiments to see exactly how it works. Take some bracketed shots of white and black objects to see how the camera handles them. In reality, bracketing is just a lazy method of exposure compensation.

[-Andrew-]

G'day


I'd just like to thank everyone again for their reply.
I still need some basic information on exposure compensation:
-more light can be let in by opening up the aperture (&vice versa)...
-a longer Tv will pro-long the entrance of light (&vice versa)...
-exposure compensation...?

What exactly does exposure compensation do to the settings?
What goes on in the camera when you set exposure compensation higher or lower?

Andrew

[Willowroot]

... and in manual mode it will only affect your meter reading.

willowroot,

So, do you mean the exposure "change" will only be displayed in the meter reading, and won't actually change the Tv or Av until the shutter button has been activated?

No, it won't change the Tv or Av at all in manual mode, since you're the one that's controlling them . . . put it this way, if you are metering a scene and you have your settings at 1/30 and f/5.6, and the meter says that is right, when you dial in +1 stop compensation, your meter will now tell you your settings are underexposing by 1 stop - so now you set the shutter to 1/15 (or your aperture to f/4) and it will show you that your exposure is correct again.  Hope that made some kind of sense . . .

Jason

[francois]

Andrew,
When you choose Av or Tv mode you are imposing a specific value to your camera. In Av mode (aperture priority) you decide what aperture value you want to use then your camera will automatically give you a speed value resulting in a "correct" exposure. This is why it's called Aperture Priority! In Tv (time value or shutter speed) mode, you decide to set shutter speed and then your camera gives you an aperture value.

Exposure correction/compensation modifies the value computed by your camera while leaving aperture (in Av) or shutter speed (in Tv) as you set it.

what situations you would use it?

Generally, you use compensation for difficult or complex subjects such as snow, white sands, lava beds, heavy backlit situations. This is true for scene that are not middle-toned.
In other words when you feel that your camera meter will be fooled.
Other situations are when you want to have a personal spin to your photos. Sometimes you want to under-expose to get darker photos and more deeply saturated colors.

Michael has an excellent tutorial about exposure.

By the way, use slides to experiment.

Hope this helps - write back if it doesn't.

Francois

[francois]

By the way, use slides to experiment.

I saw you're using an Elan-7 (EOS 33) camera!

francois

[-Andrew-]

By the way, use slides to experiment.

I saw you're using an Elan-7 (EOS 33) camera!

Francois, what do you mean?

Can't i use slide film?  
Or were you implying i am capable of using slide?
Andrew

[-Andrew-]

BJL,

the automated processing brings the overall lightness up to average, to "correct my mistake"

Can the poeple who develope my photos override this automated processing system?