Lens Basics: A Common Sense Guide

Telephoto Lens
(Canon EF 400mm f/5.6L)

This is the first in a series of posts on lenses.  As I've said in a previous post, for most types of outdoor photography, your lenses are far more important than your camera.  Even entry level DSLR cameras today can take great photographs when attached to great lenses.  There are good reasons to buy professional cameras, but if you're on a budget and you have to choose whether to sink your money into lenses or cameras, I'll always choose a lens. With this post, I'm assuming 1) that you're on a budget and need to plan your lens-buying, and 2) that you don't already know a lot about lenses.  This post will cover the basics of how you can plan your lens-buying future. Let me start with the basics of different kinds of lenses available to you.

Wide Angle Lens
(Canon EF-S 10-22mm)

1. Prime v. Zoom.  Prime lenses are lenses fixed on a single focal length.  If you buy a 50mm prime lens, you will only be able to shoot at a 50mm focal length.  Zoom lenses cover a range of focal lengths.  for instance, a 17-85mm lens will give you a zoom range that covers most types of general photography.  Prime lenses are generally sharper and faster than zoom lenses, so you are more likely to get better image quality with one of these lenses.  Zoom lenses are very convenient, and they can be very high quality lenses.  But generally speaking, they are slower (they have a smaller maximum aperture) and are not quite as sharp.
2. Wide Angle v. Telephoto.  Wide angle prime and zoom lenses let you cover a broad area in one photograph, and they tend to emphasize a feeling of depth.  Objects in the foreground will appear larger relative to objects in the background when compared to the way your eyes see things.  Telephoto prime and zoom lenses let you "get close" to objects far away.  These lenses tend to de-emphasize depth, since objects in the the foreground will not be as large relative to objects in the background when compared to the way your eye sees things.
3. Pro v. Consumer. Not all lenses are made equally.  Professional lenses use higher quality glass, they're faster and sharper, and they are built to be more sturdy. They are also larger and bulkier than consumer lenses.  Consumer lenses are more affordable and convenient for those on a budget, but not all consumer lenses are created equal either.  Some consumer lenses are fantastically sharp and useful.  Others, to put it bluntly, are not.  Unfortunately, many of these lower quality lenses are "kit" lenses that come with entry level cameras.
4. Full Framve v. APS-C.  If you have a full frame camera (many professional cameras are full frame), you need to make sure you buy lenses made for full frame cameras (Canon calls these EF lenses, and Nikon calls these FX lenses).  If you have a smaller, APS-C sized sensor on your SLR camera (this is true of most consumer DSLR cameras), you can use both types of lenses.  That is, you can use both Canon's EF and EF-S lenses or Nikon's FX and DX lenses.
5. IS/VR v. Non-IS/VR.  Most current lenses being made now have image stabilization (IS); Nikon calls this Vibration Reduction (VR).  This is a great newer feature of lenses that help you get sharper images when hand-holding.  If you hand-hold while shooting, this can be extremely helpful, especially in low-light situations.  If you only shoot on a tripod, this feature is pointless, and in fact, you'll want to make sure you have it turned off when shooting with a tripod.

The effect of a wide-angle lens on perspective
(Canon EF-S 10-22mm)

If you are new to photography and on a budget, you may not know exactly what your interests are. If that is true of you, my advice is to buy a good, solid mid-range zoom lens for more general use.  Go a step up from the "kit" lenses that come with your camera, and buy your lens separately from your camera if you can.  On a APS-C camera, a good zoom range beginning in the 15-18mm range on the wide end and ending at the 85-135mm range will suit you well for most uses.  There are many great websites that will tell you in detail the strengths and weakness of any lens.  My favorite is dpreview.  Make sure a reputable website positively reviews the lens you want to buy.  Don't trust user reviews on Amazon, etc.  Some user reviews are very good; others, well, are not.  Dpreview can be very technical, but the last page of the review has a no nonsense summary with pros and cons that will be very helpful to you as you consider what to buy.

Macro Lenses let you focus closely on your subject
(Canon EF 180mm f/3.5L macro)

As you grow as a photographer, you will develop interests.  You may decide you like expansive landscapes, and you want a wider lens.  You may decide you want to shoot wildlife, and you want a longer lens.  Or, you may decide you like portrait photography, and you want a super-great prime lens in the 50mm to 100mm range.  But the more you shoot, the more you learn about photography and your interests, so you can plan better buying choices in the future. Once you know those interests, you can save for that great 10-22mm wide angle zoom, the 180mm macro lens, the 85mm lens for portaits, or the 400mm telephoto lens.  This is just a sample of the kinds of interests you may develop, but your lens buying choices should be based on your shooting habits, rather than something you think you may like.  And it's here that you can save up and buy professional quality glass.  It's what you love the most about photography, so you can invest the most into that kind of photography.

Up Next: Mid-Range Zoom Lenses