Archives: 2008 July

Objects in good focus in a digital photo is a very basic requirement for high quality photography. There are two different ways to focus on such objects: manual or automatic. There are a few automatic focus methods – combined auto focus systems use more than one such method.

It takes a combination of many optical parameters being set perfectly to create a high quality sharp and crisp photograph. One of the most vital optical parameters is focus. A photograph with objects out of focus appears blurry and lacks details and clarity. When objects are in focus the result is both sharp and crisp.

While the photographer can manually set the focus, most of the time the digital camera’s automatic focus is much faster and easier. There are many different methods and algorithms to automatically establish the right focus for the situation that a digital camera uses. Passive and active auto focus are two of these algorithms. These two algorithms in particular are used in one type of combined auto focus system to provide excellent automatic focus.

Active auto focus systems use distance sensors measuring the distance from the camera to the objects in the scene. Typically the camera measures the distance to the object or objects at the center of the photo. Once determining that distance, the camera can then set the camera lenses to attain good focus. The ability to work in total darkness is one of the biggest advantages of active auto focus. This feature does have its challenges in unique situations. Active focus can fail to work when objects that emit certain energies (like infrared) are photographed or when surfaces in the scene absorb the energy used to measure the distance.

Photoshop can seem overpowering at first glance due to the program’s lack of simple tutorials and seemingly challenging interface. Cast your worries aside, because the basics of Photoshop are much easier than they might appear.

Upon first inspection you will see that Photoshop is basically made up of four areas: the menu bar, at the top, the toolbar just below it, the toolbox on the left and the palettes on the right. The different modes and options you can choose are located in the menu bar and toolbox which always stay the same. The toolbar will change with the context.

The palettes are there to show the current status of your image, including the history of all the actions you have used and a thumbnail overview of how the ‘big picture’ currently looks.

As an example of how the interface changes as you use it, select the type tool from the toolbox (looks like a capital T). Note how the toolbar changes completely to permit changes to the font name, size etc.

In the history palette, your use of the type tool will be added to your history, and a new layer will be created for your text and shown in the layers palette.

Whatever you’re trying to do in Photoshop, then, the chances are that your starting point will be either the toolbox or the menus. While the toolbox contains everyday tools such as selecting, filling and making shapes, the menus have more complicated functions like blurring, sharpening, and all the other effects Photoshop can achieve (mostly to be found under the Filter menu).

With the spot healing tool, you simply click on or drag across the flaw you want to remove and it disappears. The retouched area is blended into the surroundings seamlessly – most of the time anyway. It takes a little practice getting a feel for how brush size and healing work together, but most of the time it does an impressive job.

RESOLUTION. The “Auto” resolution button on the right of your Image Size dialog box will resize your image to small, medium and larger sizes. Under “Document Size” in your Image Size box, you’ll see a place to enter the desired resolution. For the Web, normal resolutions will be 72 pixels per inch. For print work, the resolution should be at least 300 ppi. When you increase the resolution, you increase the image size, and may need to resize it, but the resolution will stay the same. COLOR CASTS. Go into your Image > Adjustments menu and try using the automatic presets there: Auto Levels, Auto Contrast, Auto Color and/or Variations. This last option is especially fast and flexible, offering fine-tuning for shadows, midtones and highlights as well as saturation.

You’ll see a variety of preset gradients displayed, from the default Foreground to Background gradient to the more complex Chrome gradient. All these preset gradients can be edited to create new gradients. You’ll notice that some gradients have more colour ’stops’ than others; the Foreground to Background gradient has two colour stops – black and white – while the Spectrum gradient has seven colour stops. You can modify a gradient by changing the colour of the stops – simply click on one and choose a new colour from the Color Picker. Alternatively, click on an image and sample a colour for your customised gradient using the Eyedropper Tool.