[wp_ad_camp_1] A common question when starting out is, “What’s the best lens to get for my Canon DSLR?” Frustratingly, the answer always is: It depends. . . Everyone’s situation is unique and your lens choice is dependent on a number of factors and what you’re looking for. So instead of giving you a specific lens to go out and buy, let me provide you with a Canon lens buying guide to understand lens specifications so that you can go about choosing your own best lens.
Lenses may be the most important pieces of equipment that you can buy for your camera. You can have the most expensive camera body, but paired with bad glass and you’ll end up with sub par footage. For the most part, lenses will outlast your camera body so it’s a good idea to spend some time learning about lenses and what all those crazy acronyms mean. You can also consider renting lenses online or at a local photography shop. You don’t need to only buy Canon lenses. There are many other lens brands, such as Zeiss and Tokina, which produce lenses compatible with Canon bodies. You can even buy adapters for lenses that weren’t specifically made for Canon DSLRs or are older lens models. But for simplicity, I will just refer to characteristics of Canon manufactured lenses below:
EF (Electro-Focus) vs EF-S (Electro Focus-Short Back)
EF and EF-S are the types of camera mounts (the connector of the lens and camera body) for modern Canon DSLRs. Electro focus means that there is a small motor in the lens that controls the focus.
EF mounts have been around since 1987. EF-S lenses were designed for crop sensor camera bodies and have been around since 2003. Crop sensor cameras (such as the Canon Rebel line) can use both EF and EF-S lenses. However full frame cameras (such as a Canon 5D) are NOT compatible with EF-S lenses, and can only use EF lenses.
You can differentiate between EF and EF-S lenses by the red or white dot on the lens. A red dot means the lens is an EF lens and is compatible with full frame and crop sensor cameras. A white dot means it is an EF-S lens. There will also be matching red and/or white dots on the camera body itself.
Focal length refers to how far the lens’s optical center is from the camera’s image sensor when focused on a subject at infinity (very far away). The focal lengths are identified by the “mm” numbers, for example a “Canon EF 50mm f/1.2 L USM Lens” has a focal length of 50mm. The focal length determines the field of view you’re able to capture with your camera. The larger the focal length, the more magnification the lens will produce and the larger the subject will be.
Focal lengths are usually broken into 3 categories: wide angle, standard, and telephoto. You’ll generally want a lens from each category to round out your collection.
Wide angle lens
A lens is considered wide angle if the focal length is below 35mm. Wide angle lenses are often used for landscapes as they are able to capture a great expanse, from everything right in front of you to way into the horizon and up high in the sky. You can also use wide angle lenses for interior or tight spaces where you wouldn’t be able to move far enough away from the subject to capture everything with a normal lens. Wide angle lenses also produce a greater depth of field.
Standard lenses are those with a focal range near 50mm (35-70mm). A 50mm lens on a full frame sensor is about equivalent to what the human eye sees. Standard lenses are commonly used for street or documentary style shots.
Lenses with focal ranges larger than about 70mm are considered telephoto lenses. Telephoto lenses bring distant objects closer and are useful for capturing wildlife or sports where it’s difficult to get close to the subject. Longer telephoto lenses have a shallower depth of field.
Minimum focusing distance
For each lens, there’s a minimum focusing distance, meaning that if you shoot a subject closer than the minimum focusing distance, no matter what you do, your camera won’t be able to find focus and you’ll end up with blurry footage. Generally, the further away your lens is from the sensor the closer it’s able to focus, which is why you may see your lens extending when you are focusing. The minimum focusing distance is usually printed on the lens or listed on a dial.
Focal length and the image conversion factor
As mentioned earlier, there are different sizes of camera sensors. The focal lengths listed on camera lenses apply to 35mm film format or a full frame sensor. If you are using a camera body with a crop sensor this means the image sensor size is smaller than a 35 mm film format so you’ll need to multiply the lens’s focal length by the crop factor. For example, if using a T3i with a crop factor of 1.6, a 50mm lens will actually act like an 80mm lens (50 x 1.6 = 80).
Focal length also affects perspective
Although you may keep the subject the same size, using different focal length lenses will produce different results by altering perspectives. When using smaller focal lengths, more of the background will be captured. Alternatively with telephoto lenses, the background view will be narrower and appear closer to the subject. The larger the focal length, the more the scene appears compressed with less of a visual separation between foreground, mid ground, and background. Consequently, the distance between objects appears to be minimized, and objects that are far apart appear to be closer together.
Secondly, lenses can create an exaggerated perspective by making subjects located closer to the camera appear significantly larger while subjects farther away appear smaller. Lenses with shorter focal lengths can increase this exaggeration to make close subjects appear even bigger and farther subjects appear even smaller.
Zoom vs Prime
Prime lenses have a fixed focal length and so will only list one mm number (for example, the EF 50mm f/1.4 USM lens). On the other hand, zoom lenses allow the camera person to vary the focal length within a pre-defined range. For example, the EF-S 18-55mm f/3.5-5.6 IS II lens, has a focal range from 18mm to 55mm. (You can find a list of available Canon Zoom lenses here.) The benefit of more flexibility with a zoom lens is obvious so why would anyone choose prime lenses over zoom lenses? Prime lenses are usually cheaper, lighter, and offer larger maximum apertures, the benefits of which are explained in the next section.
Aperture numbers, represented by f numbers, correspond to how big or small the lens can open up or close down to in order to let in more or less light. The larger the f number, the smaller the lens opening is. Aperture is a very important concept for DSLRs so we’ll spend a whole different section on the topic. For now, just know that the aperture numbers listed in lens descriptions refer to the maximum aperture (how wide the lens can open up to). Zoom lenses may come with fixed or variable maximum apertures. For example, if your lens listed the aperture as f/3.5-5.6, that means the maximum aperture will gradually decrease from f/3.5 when fully zoomed out to f/5.6 when fully zoomed in. Constant apertures are preferred to maintain exposure settings when changing between focal lengths. Larger maximum apertures allow more light to reach the sensor for better low light performance and to create a shallower depth of field.
The filter size indicates the filter ring diameter. The filter size is indicated with the Ø symbol. Everything that you screw on or place on your lens (lens caps, filters, lens hoods) have different filter sizes to match different lenses. You’ll want to match the accessory’s size with the lens filter size. You can also buy step up or step down rings to fit your lens to a mismatched accessory filter size.
Image Stabilization (IS)
When movies are all about keeping the image as shake free as possible, lenses with image stabilization are a huge asset. IS lenses are able to detect movement and offsets it to create a more stabilized image.
USM: Ultrasonic Motor
Lenses with USM (Ultrasonic Motor) have quieter auto focusing. When you need to be discreet, this lens is good for the job. For example, when working with animals, you don’t want to miss the perfect shot because you scared the animal away with the whirring noise produced from auto focusing. There are two types of USM: Ring-type USM and Micro USM. Ring type USM lenses are used in large aperture super telephoto lenses and offer full time manual focusing. Micro USM is used more in compact lenses. USM lenses are much faster to focus than non-USM lenses. The motor starts instantaneously and instead of overshooting, it will immediately stop when focus is achieved. Whether you’re filming action sports or trying to capture your kids running around, a faster focusing lens is always better. Finally, USM lenses require minimal battery power enabling you to shoot for longer periods. Unfortunately, these conveniences come with a price. . . a more expensive one.
STM: Stepping Motor
STM lenses are designed for video. These lens are even quieter than USM lenses and focus more smoothly. More STM lenses are being released for compatibility with the recently added function of continuous auto focus during movie shooting.
The II or III means that there are multiple versions of the lens. I hope you remember your Roman Numerals from elementary school days or from watching the Super Bowl. II means version 2. III means version 3 and so on. The bigger the number, the more recent version it is. Canon may have decided to update a lens to add another feature and so produced another version of the lens.
L – Luxury Series Lenses
L lenses are considered the best of the Canon lenses and are recognized by the familiar red stripe around the lens. Among other things, they produce sharper images, are more solidly built (most often weather proof), and have larger maximum apertures (remember that means a lower f number). That said they come with hefty price tags. (A list of available L lenses can be found here.)
DO: Diffractive Optics
DO lenses have a reduced weight and size compared to other lenses with similar focal lengths.
UD: Ultra-Low Dispersion
UD lenses can achieve enhanced image quality and sharpness by reducing chromatic aberration or “color fringing” around subjects.
Theses lenses are able to create super sharp images, but they also have the option to add soft focus to create a smooth dreamy aesthetic.
Full-Time Manual (FTM) Focus
Some lenses may be described as having full time manual focus which allows for manual focus even when the auto focus (AF) switch is on. This is useful when you want to use auto focus but then quickly make some manual adjustments without having to switch back and forth between auto and manual focus. On non-FTM lenses if you try to manually focus while your lens is on auto focus, you could damage the motor.
TS: Tilt Shift
Tilt shift lenses allow you to manipulate vanishing points. For example, when shooting buildings usually the vertical lines will appear to tilt. You can correct the tilted lines by using tilt shift lenses. Tilt shift lenses are also used to selectively focus an image where two subjects can be on the same plane but only one subject is in focus. Tilt shift lenses are also commonly used to make your scene appear miniaturized.
Macro lenses are mostly used for extreme close up shots of small objects such as flower petals. Macro lenses can capture minute details that would ordinarily be looked over.
Fish-eye lenses are extremely wide angle lenses that provide a 180° view but with a circular distortion where straight lines become curved.
So now that you know how to pick a lens, it’s time to check out the Canon lens lineup.
If you’ve already got some lenses in mind, I recommend checking out the image quality comparison tools at the-digital-picture.com. But if you still need help deciding which lens to choose, you could also check out the great resources at LensHero.com.