For some reason, almost everyone starting out in photography wants a big telephoto lens. Are we compensating for some inadequacy? Probably not, but they look darn impressive and lend a professional look to the photographer carrying one around in the field (Figure 1).
In the old film days it was common to have a camera come with a 50mm lens. This focal length gives you nearly the same field of view as the human eye.
Because a fixed focal-length lens isn’t commonly included with a camera these days, a 50mm is often an early purchase choice for many photographers. These lenses are normally inexpensive, small, lightweight, and have a fast aperture (f/1.8 is not unusual, and if you’re willing to spend more you can go as fast as f/1.2), making them ideal for shooting in low-light situations.
Wide-angle lenses (Figure 1) are a favorite of both landscape and indoor photographers because of their ability to capture large areas in a single image. Wide-angle is generally considered to be anything less than the 50mm focal length equivalent on 35mm film.
Zoom lenses are a popular compromise for many users. The advantages are obviousyou get the equivalent of many different focal lengths all in one compact package. Most “kit lenses,” or those that come with a digital SLR, are zoom lenses that cover the wide-angle to telephoto range (Figure 1)
Modern lenses are complex creations with specialized coatings on the glass to optimize color quality and image sharpness. Figure 1 shows a cross-section illustration of a zoom lens. As you can see, multiple lens elements make up a modern lens.
Many advanced compact cameras support raw image capture, but few are optimized for it All digital SLRs support raw, and many are capable of recording images in raw and JPEG at the same time. Which format is best?
For pure image quality, you can’t beat raw. The raw format is simply a recording of the light values as seen by each pixel when the image is captured on the camera sensor. There are no modifications made to the data, and it’s stored in the full bit depth supported by the camera (typically 12 bits) for the maximum color information.
If you’re used to shooting with a compact digital camera, you’ve probably learned to stay away from anything but the lowest ISO settings, such as 100 or 200, because of noise problems associated with more light-sensitive ratings of 400 or higher.
Luckily, digital SLRs are much better in this regard, and images shot at ISO settings of 400 and as high as 1600 are very usable. Why would you want to use these higher settings? There are two main reasons. The first is to give you more exposure options in low-light conditions, and the second is for creative techniques.
Shutter Priority, also known as Time Value or TV on some cameras, is the best choice when you want to control how long of an exposure you take and don’t care as much about the depth of field. An example of this type of image capture is sports photography, where you really want to freeze the subject in motion. Another is where the wind is blowing, and you want to avoid the blurring of trees, flowers, and grasses.
Aperture Priority, sometimes referred to as AV or Aperture Value, is used when you need to control which parts of your image are in focus. Landscape and portrait photography are almost exclusively shot with Aperture Priority and for exactly the same reason, even though the desired results are polar opposites.
Aperture controls depth of field in your images by changing the size of the diaphragm in the lens to control light. Smaller numbers, like 4.0, 3.5, and 2.8, mean a larger opening (Figure 1) which allows more light to hit the sensor in less time. This also gives you less depth of field, or range of focus.
The first stop for almost everyone is Program mode. Usually identified with a P (Figure 1), this mode puts all control in the hands of the camera. Both aperture and shutter speed are set automatically, based on how the camera senses the available light, which lets you concentrate on learning how to compose and focusideal for someone just moving into a full-featured camera.
