November 1, 2011

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Jon's DSLR Buying Guide: Part 2 – The Lens

This is part of a multipart series on buying a DSLR. For the camera, see Part 1.

Once you’ve selected a camera, you need to get a lens (or two, or three ^_^ ). If you’re buying a Nikon, you don’t need to worry about them fitting. All Nikon cameras that we care about (and most of the lenses) since 1959 use their F-mount system. Canon isn’t so lucky, but they’ve been pretty good about standardization too (from what I understand). As with the camera, lenses come in a variety of shapes and sizes with their own classifications of “types” and their own set of numbers/features/doodads.

First, let’s quickly look over the typical classes of lenses (and what each means):

  • Wide Zoom — These are zoom lenses that are the widest angle you can get, typically between 10-40mm.
  • Zoom — These are the standard lenses that most people will get and run between 20-120mm, but sometimes as high as 200mm.
  • Telephoto Zoom — These are the fun stalker mode (or sports/wildlife) zoom lenses. They’ll run in the 70-300mm range.
  • Single-Focal Length — Also known as “Fixed Focal” or simply “Normal”. These are the good old fixed lenses. If you’re not used to it, they are strange to work with because you cannot zoom at all. You have to move yourself around your subject.
  • Special Purpose — This is basically anything that isn’t covered in the above list. Such as: Macro, Fisheye and Perspective Control (aka Tilt shift).
If you’re REALLY new to photography, you’re probably confused by the measurements used above. The numbers I’m giving you are called the Focal Length (warning: Wikipedia link is not human friendly) and are measured in mm (millimeters). All you really need to know is that smaller numbers means more zoomed out and bigger numbers mean more zoomed in (example). If you want to take pictures indoors (close up), you’ll want a smaller focal length and if you plan to be far away from your subject (sports, nature, stalking people) then you want the biggest focal length you can get. The bigger the range of the lens, the more expensive.

The other feature you’ll want to keep in mind is the F-stop. Your typical F-stop range is between F/1.4 and F/22. F-stop effects the depth of field in your pictures. You can read about the technical differences on Wikipedia, but the simple version is that a smaller F-stop means less of the picture is in focus (shallower depth of field) and a bigger F-stop means more is in focus (example). Those really small F-stops give you the fancy art look as demonstrated by my self-portrait on the right. Any lens you buy will list an F-stop number, that is the lower end limit (the upper end is always F/22). The lower the F-stop, the more expensive the lens.

Let’s take a look at the lenses I carry:

  • Nikon 18-135mm f/3.5-5.6G ED-IF AF-S DX Zoom-Nikkor Lens — This is my “every day” lens. It has a good focal range (18mm to 135mm) meaning that I can use it indoors and get a wide angle, but still use it at a distance if I need to. The f-stop is variable between f/3.5 and f/5.6 (the more zoomed, the higher the f-stop) — as long as I’m zoomed all the way out I can use f/3.5 and that isn’t too bad. You’ll also notice a bunch of letters and acronyms after the F-stop, those are specific to each lens manufacturer and you’ll just need to look up what they mean. In this case ED means extra-low dispersion and IF means internal focusing.
  • Nikon 50mm f/1.8D AF Nikkor Lens — This is my fun artsy lens. It is a fixed (or single) focal length of 50mm, but in trade I get a really low f-stop of 1.8.
  • Sigma 70-300mm f/4-5.6 DG APO Macro Telephoto Zoom Lens — This is one of the original lenses I purchased and is a big telephoto. When I go to events like the Reno Air Races, I use this lens for the races themselves. Though, if I were to get a new telephoto now, I’d get a Nikkor lens with vibration reduction.
If you’re not looking to get too fancy with your lenses, I’d recommend a zoom lens and not worry too much about the f-stop. Something like the Nikon 18-105mm f/3.5-5.6 AF-S DX VR ED Nikkor Lens gives you a nice range. If you were interested in more range (perhaps you’re predominantly taking pictures at Little Bobby’s soccer game) then the Nikon 55-300mm f/4.5-5.6G ED VR AF-S DX Nikkor might suit you better.

While one of the major features of a DSLR is the fact that you can change the lens, most people don’t use it. If you’re new to the game, don’t bother getting multiple lenses unless you’ve got more money than sense (or are taking a once in a lifetime trip and an extra grand on lenses is nothing). If you buy multiple lenses you need to worry about switching them out in the appropriate situation (and learning what those situations are) AND carrying them with you. I had a single lens for many years before I bought a second (followed by a third, and a fourth). Once you’ve spent some quality time with your camera, you can decided if you REALLY need that new glass.