What happens when you take a picture with a digital camera?

Some digital cameras have a device called a CCD (Charge Coupled Device) and others have something called CMOS (complementary metal oxide semiconductor).  This device converts light into electrons. Each pixel responds to red, green or blue light. The "raw" image produced by the CCD or CMOS device has a lot of data in it but doesn't look that good (yet).  It requires some kind of computer manipulation to make it look "good". Not all digital cameras allow you to save this RAW image, but most do.

JPEG Images
If you shoot JPEG images, the camera does four basic things to make the image look good before it saves it:

In doing these things, you lose some of "data" in the image.  Every time you apply some form of computer manipulation (i.e., color balance, sharpness, etc), you change the image and in doing so, lose a bit of image data. One other thing happens when you take a JPEG image - that's compression. The camera compresses the image to make it smaller.  This JPEG compression is a "loss" compression - in other words, more image data is lost to make it smaller.

The result most of the time is a pleasant looking image.

RAW Images
If you shoot a RAW image, the camera does not perform any manipulation and saves the image in its RAW form. One drawback of saving RAW images is that they're BIG - very BIG (that's your first indication that they contain a LOT of data - much more data than JPEG images).  They take up a lot of room on your memory card and take longer to save. Here's an example of an unprocessed RAW image:

It resembles the image taken, but doesn't look very good.  It NEEDS to be adjusted!  I could have done it painlessly by taking a JPG image in the first place, but I chose to take a RAW image because I trusted my ability to manipulate the image more than I trusted my camera to do this.  It's similar to taking a picture with FILM and sending it to a lab that has a MACHINE make your print. It may come out OK - but it ALWAYS could be better. Give the same negative to a PERSON to make the print and you'll always get a better print.  Same analogy here - a person (who knows how to manipulate the image) is almost always better than a machine (i.e., camera).

Here's the image after some very simple adjustments (less than one minute).

You may not want to do this to all of your digital pictures, but, it's a labor of love! It's all a matter of how much you love your images :).

Histograms are charts that show how much black, white, red, green and blue is in a picture. They can be very useful to view an image "graphically". Below are two histograms - the first is of the RAW image and the second is of the manipulated image. On the far LEFT of the histograms is "black". On the far RIGHT is "white" and the middle represents all the tones in-between. The HEIGHT of the histogram indicates the "quantity" of each tone. As you can see in the RAW image, there is NO black or white - just mid-tones. In the manipulated image, I adjusted the tonal "levels" to s-t-r-e-t-c-h them out, creating black from the darkest value and white from the lightest value. When shooting JPEG images, the camera does this for you (plus other manipulations as well). The camera's JPEG manipulations rarely create the image you really want!