Levels dialog - used for maximizing tonal range and rough brightness adjustments.
Curves dialog - fine tuning the tonal balance and contrast.
When viewing the histogram of an image, if the left side (shadow) ends abruptly this means that the image was "clipped" and that the darkest areas of the image will be rendered as solid black. This happens when the darkest areas of an image are below the image sensors detection range.
The Levels dialog is a quick and easy way to adjust the exposure of your image. Open the Levels dialog by selecting Image...Adjustments from the menu. From here you can either do Auto Levels or Manual Levels. The Auto Levels command will automatically stretch the histogram so that there is a better distribution from shadows on the left to highlights on the right. If you prefer to have more control over the results, you can use Manual Levels. With Manual Levels, you adjust the sliders under the histogram until you get your desired results. Typically, when adjusting an underexposed image you will adjust the middle and right sliders.
Indicates what lens mount the camera has.
Controls the amount of light reaching the film or light sensor. Cameras that don't have an aperture ring often have an electronic control to adjust the aperture.
Depth of Field Scale
Indicates how much of the subject will be in focus.
Indicates the distance from the subject.
Used to focus on the subject when in manual mode.
A threaded ring to attach filters.
A threaded ring at the front of the lens for attaching filters.
For adjusting the focal length.
Conveniently, most SLR cameras have an Auto Exposure Bracketing (AEB) feature that will automatically take the 3 pictures for you. You simply set the EV value and the camera will take a picture that it thinks is properly exposed, a picture that is slightly under-exposed and a picture that is slightly over-exposed.
Factors that affect Depth of Field:
- f-number: Increasing f-number (reducing aperture diameter) increases DOF (foreground & background are all in focus). Decreasing f-number (increasing aperture diameter) decreases DOF (soft/blurred backgrounds).
- Focal length of the lens: The smaller the focal length number of the lens, the greater the DOF.
- Distance: The greater the distance of the subject from the camera, the greater the DOF.
A shallow DOF is ideal for photos where you want to call attention to your subject and not be distracted by the background, for example, portraits. A large DOF is ideal for landscape photos where you want everything in focus.
A simple way to improve the composition of your photos is to follow The Rule of Thirds. Divide your view into thirds, both horizontally and vertically. Imagine drawing horizontal and vertical lines so that you have 9 evenly sized rectangles. The 4 intersection points are your optimal points for placing your subject. More and more point and shoot cameras now offer a feature where you can turn on gridlines on your display screen. This helps to quickly compose your shots.
The Rule of Thirds helps you to compose well balanced shots that will make your photos more interesting and more pleasing to the eye. This same technique is often used by artists. Even though it's called the Rule of Thirds, keep in mind that it is more of a "guideline" than a fixed "rule". Depending on your photo, sometimes the Rule of Thirds should be ignored. Each photo is unique and should be composed in a way that suits the photo.
Aperture is expressed as an F-stop. Here's where it gets confusing:
-The larger the F-stop number, the smaller the lens opening.
-The smaller the F-stop number, the larger the lens opening.
This takes some getting use to, but you need to remember that as the F-stop number increases, the lens opening decreases. Another term to be familiar with is a "fast lens". This refers to a lens with a large maximum aperture (small F-stop number).
A large aperture provides:
-Shallow depth of field (blurred backgrounds).
-Fast shutter speeds.
-Reduces camera shake.
A small aperture provides:
-Large depth of field (foreground and background are all in focus).
-Slow shutter speeds.
Here are the recommended settings for the Unsharp Mask Filter:
Radius: 0.3 pixels
Threshold: 0 pixels