So you’ve entered the world of photography with your new digital SLR – congrats! It’s can be a very rewarding hobby, and with practice, knowledge, and tools, you can produce great images. I’m often asked by family, friends, and guests at weddings I’m photographing about digital cameras and equipment. One of the things people are often most confused about is the topic of lenses. Focal length, aperture, wide, telephoto, zoom, prime – it’s a dizzying array of technical terms that might seem like a foreign language if you’re starting out. In this article, I’ll give you tips on what to look for in a lens, ‘decode’ all the numbers and letters on the side of your lens, and offer some recommendations for starter lenses.
Your DSLR might have come with a lens as part of a ‘kit.’ It may even have come with two or more lenses as a bundled package. Most people starting in digital photography opt to buy a camera with the smaller APS-C sensor (Canon Rebel series, 60D and 7D) rather than a full frame sized sensor (5D and 1DS) because they are less expensive. For the purpose of this article, the information and recommendations are based on a camera with the APS-C sensor.
There are three main categories lenses can fall into: wide, normal, and telephoto. A wide lens is one that has a focal length of less than about 35mm. These lenses will take in more of a scene, good for large landscapes and fitting a group into your frame in a tight space or small room. 35mm-70mm is generally considered to be a normal focal length, and is good for general purpose photography and is approximately the perspective of the human eye. Lenses over 70mm are considered to be telephoto, meaning that they make far away objects seem closer, much like looking through binoculars or a telescope.
Lenses can also fall into two other types of categories: zoom and prime. A zoom lens has a range of focal lengths, such as 18-55mm or 55-250mm. Many people confuse ‘zoom’ with ‘telephoto’. A telephoto lens has a long focal length (like 100mm or 200mm), whereas a zoom lens merely means that the focal length is adjustable. For instance, you can have a wide angle zoom lens, such as a 10-22mm, or you can have a fixed focal length telephoto lens, such as a 200mm lens. A prime lens is one with a fixed focal length that cannot be changed, such as a 50mm lens or 35mm lens. So why would someone buy a prime lens at all if it can be covered within a zoom lens’s range of focal lengths?
There are basically three reasons why a prime lens would be advantageous over a zoom lens. Since primes don’t require the extra moving parts or pieces of glass needed to zoom in and out, their design is simpler, which generally equates to higher quality and sharper images. They can also be made with a larger maximum aperture more easily, allowing more light into your camera, and thus making low light photography easier. They are also often smaller and lighter than a zoom lens covering a range of focal lengths. However, since they are at one fixed focal length, they are not as versatile as a zoom lens, and therefore you must move closer or farther away from your subject rather than just twisting a zoom ring.
As far as Canon lenses are considered, there are two more categories still that lenses can fall into: EF and EF-S. Simply put, EF lenses will fit on all Canon DSLRs. They have a small red dot on the base of the lens. If your camera has a red dot on the body, the lens will mount. EF-S lenses are designed for the smaller APS-C sensor SLRs, and are denoted with a small white square at the base of the lens. If your camera has a white square near the lens mount, simply align the white square with the white square (or red dot with the red dot) and mount the lens. EF-S lenses will not mount on Canon SLRs with full frame sensors. So a Canon Rebel. 60D or 7D (any SLR with the APS-C sensor) will accept any Canon lens, whether it’s EF or EF-S. A full frame Canon (5D or 1DS) will only accept EF mount lenses.
Another feature you might look for with a lens is image stabilization. This feature allows you shoot as slower shutter speeds and still get sharp images. A small motor inside the lens compensates for camera shake and “holds the lens still” while you’re handholding. Another useful feature is called USM – ultrasonic motor. These autofocus motors are faster, smoother, and quieter than non-USM lenses. This is useful for sports, wildlife, or if you want to be inconspicuous, like in a quiet environment or around subjects that can be easily startled like animals and children.
There’s a lot of numbers and letters on a lens, sometimes on the side, sometimes on the very end. It can look like a cryptic code if you don’t know how to read it. As an example, I’ll use the 15-85mm lens, a great “do it all” lens. On the front of the lens, you’ll see it reads “Canon Inc.” – simple enough, it’s a lens made by Canon. You’ll also see “Canon Zoom Lens EF-S 15-85mm 1:3.5-5.6 IS USM”. “Canon Zoom Lens” means that it’s a zoom lens with a range of focal lengths. “EF-S” means that it’s an EF-S mount lens, not an EF mount. “15-85mm” is the range of focal length the lens covers – this lens is a general purpose lens, covering a pretty wide 15mm, and zooms into a short telephoto 85mm focal length. “1:3.5-5.6” refers to the widest maximum aperture. At its shortest focal length, the widest the lens’s aperture will open is f/3.5, and at its longest focal length, the widest the aperture becomes f/5.6. “IS” means that the lens is equipped with image stabilization, mentioned earlier, and “USM” if you haven’t already guessed, means that the lens is equipped with USM for faster and quieter autofocus.
An example of another lens is the 50mm f/1.8. On the end of the lens, it reads “Canon Lens EF 50mm 1:1.8 II” Basically, it means that it’s a Canon EF lens (not EF-S), it has a focal length of 50mm, and it has a maximum aperture of f/1.8. “II” means that it’s the second version of this particular lens. There is less information on this lens than the 15-85 because it is a simpler lens; it is a prime lens, so there’s no range of focal lengths, only one. Being a prime lens, it doesn’t have a range of maximum apertures based on zoom, so simply, f/1.8 is the widest it will open. There is no IS or USM with this lens either, so they are not listed. Separate from all the other information, you might see a number, such as “58mm” or “72mm” – this refers to the size of the threads on the end of the lens to accept a filter. If you plan on using a filter, you must get the filter that matches the size of the filter threads on the lens – a 72mm filter will only mount on a lens with 72mm filter threads. A step-up ring allows you to use larger filters on a lens with smaller threads so you can use one filter for two lenses. For instance, with the use of step up rings, you can use a 77mm filter on a lens with 77mm threads, 72mm threads, 62mm threads, etc. Just be sure the filter size is the same size or larger than the corresponding threads on your lens.
So what lens should you buy? It’s largely dependent on what you shoot and your budget. Shooting landscapes and interiors? A wide angle lens will likely be your best bet. Sports and wildlife? A telephoto lens is probably a better choice. Do you want the versatility of a zoom lens, or the quality and speed of a prime lens? How much do you want to spend? These are all questions to think about before you decide to plunk down hundreds of dollars on a lens. My advice is to decide what features you want in a lens before you go shopping. Below are several recommendations for good beginner lenses. None are overly expensive, but they can provide very good image quality.
18-55mm f/3.5-5.6 IS II – sold as the kit lens for Canon’s Rebel series, it’s a great place to start, with a normal range of focal lengths and surprisingly decent good image quality
55-250mm f/4-5.6 IS II – a great match for the 18-55, it offers a long zoom range, and a long telephoto focal length. If you’re looking to get in close on a budget, this is the lens for you.
18-135mm f/3.5-5.6 IS – a great do-it-all lens, it covers everything from wide to telephoto, and makes for a great general purpose use.
28-135mm f/3.5-5.6 IS USM – 10mm longer on the wide end than the 18-135, but it adds USM, so autofocus will be faster and quieter, which is always welcome.
A myriad of prime lenses will offer wider maximum apertures, sharper and higher quality images, and a compact, lighter size than most zooms. Here are a few that I recommend for someone looking to get into shooting at a fixed focal length: 24mm f/2.835mm f/2, 50mm f/1.8, 85mm f/1.8 USM, 100mm f/2.8 Macro USM.