you can set the Av and Tv by turning the dials until the meter is zeroed. a raw image is a format used by high end SLR cameras to produce high quality images. just like JPEG, PNG, or BMP.. it is just a format name. you can convert it using photoshop and save it to JPEG to process, and print it. :sweat:
exposure is determined by 3 factors on a dSLR. shutter speed, aperture, and ISO.
shutter determines how long the shutter is open for - longer means more light. aperture means how large the opening is, and ISO is film sensitivity - the higher the ISO, the more sensitive.
if you want to read more, there are plenty of tutorials and explanations on the net...
as for RAW. this is the format that the camera stores the information take in.it doesnt do anything in itself. but in order to print email the image etc, you will need to convert it using a raw converter.. any camera that comes with RAW ability, should have a software converter as part of the package. photoshop can also convert raw.
Sound like you need some basic photography books or basic photography courses. Main thing to take note is metering, shuttler speeds, aperture and sensor setting or films choice. These basic make or break a picture.
The relationship between shutter speed and aperture can be imagine as a calculation on the amount of volume, in photography sense, it is the amount of light.
If your aperture is big (f1.8) and your shutter speed is slow (8"), you get a large volume which in turns a large amount of light which might lead to overexposure. On the other hand, if your aperture is small (f22) and your shutter speed is fast (1/8000), you get a very small volume which means a small amount of light which might lead to underexposure. The aperture also controls the Depth Of Field. The bigger the aperture (f1.8), the shallower the DOF. The smaller the aperture (f22), the greater depth of field.
For ISO, the higher the ISO, the more reactivity it is to light, but at the expense of noise. So if you combine the 3 factors together, it is very much the fundamental of photography.