As a photojournalist, it is important for things to look as realistic as possible. Some photojournalists prefer to use black and white (James Nachtwey for example), and some like to use color (Remi Ochlik). I shoot both black and white and color because I believe there is a time and place for both.
HDR, retouching, etc. have traditionally been considered taboo in the photojournalism field, but are they wrong? Again - my standpoint on this issue is that there is a time and place for everything. Have I composited a more interesting sky into my images? Yes. Have I used HDR? Yes. Have I retouched someone's face? Yes. Have I sold an image straight out of camera? Also yes. A few times.
Wait... what? Am I crazy? (Click read more if you can't see rest below.)
Neither the HDR photo or the Giza photo have been used on a magazine cover. I also am limited a bit on where I can show them because some galleries and magazines still consider techniques like that as big no-nos. For example, National Geographic, Outdoor Photographer, and the New York Times.
Digital editing software is a great gift that we now have available at our disposal for a relatively-reasonable price. In the past, film was "edited" with dodging and burning, and it did indeed take people a while to come around to these techniques when they were first used. Yes, enlargers are expensive, and developer, film, and other chemicals also not cheap in the long run, and neither is software.
However, too often do I hear other photographers say things like "it's okay I can fix that in post." Don't fall into that hole! It helps to know how to do things correctly in camera, because then you can use the software for what it is for: to enhance the photograph, and you may not have to buy as much of it.
Are you planning to shoot portraits? I get a lot of clients asking me to "fix" things about them they don't like. Lighting and wardrobe choice will also "fix" those things for them, and those tools are a lot less time-consuming for the same price.
-----Apertures / F-Stops------
If you're going to photograph something that is far away and you want the whole image in focus, you want to use a smaller f-stop. Most landscape lenses go down to f-22 or smaller. Using a bigger aperture might make either the foreground or background blurry. Likewise, if you want that effect, use a big aperture. Most portrait lenses go as big as 2.8 or bigger.
A smaller aperture is a smaller opening in the lens, and therefore less light passes into the camera. A larger aperture is a bigger hole, and lets more light into the camera. The depth of field for a bigger opening is shorter, but for a smaller opening, it is longer. (With apertures, the smaller number is a bigger opening, and the bigger number is the smaller opening.)
If you're photographing something that is moving and you want to freeze it in place, you want to use a fast shutter speed like 1/8000. If you want to blur the motion a bit, you might want to use a slower speed like 1/50 (depending on how fast the object is moving.) Advanced photographers might utilize a method called panning where they move the camera in line with the object to make it clear and crisp but everything else will have a motion blur.
A smaller shutter speed allows the aperture to be open for a shorter amount of time, often a fraction of a second. A larger shutter speed has the shutter open for a longer period of time. This is also known as exposure time. Some photographers can have their shutter open for an hour or more if they are photographing stars, clouds, or water movement. Whereas, sports photographers sometimes have their shutters open for as short as 1/8000 of a second.
ISO and ASA are the same thing. ASA is the older name for the current ISO film speed. If you are shooting digital, you can still set the ISO speed to simulate the speed the film would have. Typically an image taken with bright sun would require an ISO speed of 100 or 200. An image taken in the shade would usually be at 200 or 400. An image taken in low light or night time would need 800 or 1600. Some digital cameras go lower than 100 and some go higher than 1600. The lower the ISO number, the lower the noise you will see, and the higher the number, the more noise will be in the frame. Some photographers shoot low light at a low ISO and just leave the shutter open longer to alleviate the noise problem. Some use software to get rid of it. Some people embrace noise and even enjoy it.
Lower ISO values in low light are often used when photographing flowing water or the earth rotating under the stars.
Most DSLR cameras have the option to change the white balance. When photographing people, I like to use one of the normal settings that agrees with the lighting I am using. Sunny white balance can be used with direct, hard sunlight. Cloudy can be used when it is overcast or if the subject is in the shade. Some cameras also have a shade setting. Tungsten light is red light, so there is a setting on your camera to accommodate that and help skin tones to appear normal instead of red. Tungsten light is used inside most buildings. Fluorescent light can have a blue hue, so likewise there is a setting on the camera to accommodate that. If your camera has a K function, remember that the smaller the number the more blue the hue will be in the finished image. The larger the number the more red the hue in the finished image.
Depending on the lighting, you might not choose a dead-center setting, though. For this reason I have seen many photographers bracket even if they don't intend to make an HDR image.
At a later date, I will put out an ebook describing how to use lighting techniques to create a great image "in camera".