Lens Basics: Wide Angle Zooms

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Tree at Orlando Wetlands Park
Wide angle zoom lenses can be a great addition to your lens arsenal.  On a full-frame camera, wide angle zooms usually begin around 15-16mm and continue to 35-40mm.  On an APS-C camera, wide angle zooms usually begin around 10-12mm and continue to 22-24mm.  APS-C cameras need wider lenses to give you the wide angle experience because the sensors are smaller than full-frame cameras.  Thankfully, both Nikon and Canon make lenses specifically designed for APS-C cameras, and both have great wide-angle zooms to choose from.  In fact, Nikon has two:

Nikkor AF-S 10-24mm f/3.5-4.5G DX ED
Nikkor AF-S 12-24mm f/4 G DX ED
Canon EF-S 10-22mm f/3.5-4.5 USM 
Effects of Wide-Angle Lenses on
Relative Sizes of foreground and background
Make sure you read reviews of these lenses to make sure they are right for you.  Wide-angle zooms are fantastic because of the way they mess with your perception.  Because they take in such a wide angle of view, they emphasize a sense of distance between the foreground and background.  This has two wonderful effects:
  1. Objects in the foreground will appear to be much larger than objects in the background.  Put a leaf or flower in the foreground and a mountain in the background, and the leaf may seem larger.
  2. When the camera is pointed either up or down, objects will appear to bend toward the center of the frame the farther away they are from the focal plane of the camera.
Wide-Angle Lens Looking Up
In reality, your eyes have the same "problems" as these lenses.  To your eyes, objects in the background appear smaller relative to objects in the foreground (that's one way we judge relative distances), and tall objects tend to bend toward the center when we look up.  But these things do not happen as dramatically as in wide angle lenses, and we're accustomed to the way our eyes see things.  Wide angle lenses make things look a little strange because these effects are more pronounced at wider angles.

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Notice the Lighthouse Bending toward the Center of the Frame,
and notice that it doesn't appear to be perfectly round
Sometimes we use wide angle lenses simply to include a wide angle of view in one photograph.  But I think that wide-angle zooms are best used when you exploit at least one of the two effects listed above.  Put something in the foreground or intentionally make things bend toward the center. When choosing a wide-angle zoom, there are some issues to look out for:
  1. These lenses often have problems at the wider angles of the zoom: barrel distortion (straight lines look curved), color fringing (the wrong color appears along the edges of objects), vignetting (the corners and edges are darker than the center), and loss of sharpness along the edges of the frame.  Many of these can be improved with software, but you still want to make sure that you start out with a good image.
  2. Your circular polarizer (CP) filter may not work well for two reasons.  1) If you'll remember from my post on CP filters, they work best when shooting at right angles to the sun.  Because wide-angle lenses take in such a wide field of view, the effects of a CP filter will be uneven. 2) You may have increased vignetting.  You can buy special CP filters that are extra thin--there's no threads on the front to let you stack filters.  You may find this type of polarizer necessary at the wider range of your zoom lens.