Picking the right lens for the job is like picking the right club in golf. Just as you wouldn’t necessarily pick a 9-iron to tee-off, you wouldn’t pick a 35mm lens to make a portrait. Pardon me for using a golf allegory, if you are not familiar with the sport, but you get the general idea. You can’t fit a round stone in a square hole; you need the right tool for the job.
The lens of your camera (and this goes for all cameras regardless of make, model and type), is the eye through which it sees. Light traveling through the lens and then through the aperture exposes the scene to create the image. One of the key aspects of this is a thing called focal length. You will hear more about it as you progress. The focal length determines how far a lens can see. It is a numerical number that represents a measurement of distance from the point which is considered an optical center of the lens and the imaging plane, which can be film or the digital sensor. You can read up more about lens construction in our Understanding camera lenses article.
The focal length determines the angle of view of the lens. Angle of view is simply how much the lens can see, left to right. Any lens that can see roughly what the human eye does is considered a standard lens. That would be your 50mm lens (for full-frame cameras).
Typically every category of lenses, be it wide angle, standard or telephoto, have certain classical uses which I’ll describe below. Knowing these basic uses can be very helpful when selecting the right lens for a job. But don’t let nobody tell you that you CAN’T use a certain lens for something, there are no judicial laws about it. Once you know your way around your perspective, you can easily bend the rules and create unique imagery by using the “wrong” focal length.
So, standard lenses are those which you should use for capturing anything that you wish to be captured at the same perspective as the human eye. Standard lenses like the 50mm primes are sought after by hardworking candid photographers because they can’t be zoomed and thus you have to rely on your intuition and feet to be at the right place at the right time. This actually helps you to become a better photographer.
You wouldn’t necessarily shoot portraits with a 50mm though. This is because any lens 50mm or wider will distort facial features when used at a close range. For portraits a slightly longer focal length is better suited. A very popular lens is the 135mm. For some photographers that’s the go to lens for portrait photography. 85mm and 100mm are also considered excellent lenses for portraits.
Anything wider than 40mm would typically be considered a wide angle. Cameras with a full frame sensor would produce wider images than those with a crop sensor. A crop sensor would capture smaller frame and thus give an illusion of a narrower focal length. So a 24mm lens on a 1.6x crop sensor would look like 38mm (1.6×24=38.4) on a full frame sensor. If that confuses you, check out our Deciding on Full Frame Sensor vs Crop Sensor article.
Wide angle lenses are great for capturing landscapes, interiors and anything else that benefits from a wide field of view. While these lenses are great at capturing indoor events, especially in tight places, keep in mind that they also skew perspective. The wider the focal length, the larger the distortion would be. By using wide angles you can easily make people look like a caricature of themselves and even make straight walls look curved. They can be great for capturing unique moments, but at a cost of making people and architecture look a bit unrealistic. Some of the distortion can be fixed in post-processing by applying a specific profile for your lens in editing software, but any substantial distortion can rarely be fixed flawlessly. This is also why many professional architecture photographers prefer using tilt-shift lenses (described further).
Wide angles that go beyond ultra-wide length are also referred to as Fisheye. An 8mm lens, for example, would create an image circle in the middle of a frame and leave the rest of it black.
Telephoto lenses, 200mm and above, are used predominantly to shoot wildlife, sports and action, basically anything that needs tighter framing, but is difficult (or dangerous) to get close to. Telephoto lenses have a larger magnification making it possible to bring the image ‘closer’. Because of this, telephoto lenses have a smaller angle of view, meaning the left to right frame coverage becomes smaller.
Telephoto lenses are also great for background compression. Background compression happens because telephoto lenses tend to pull more of the frame towards the camera when they lock focus on something further away. The longer the lens, the more exaggerated is the result.
Tilt-shift lenses are very specialized. They have been designed primarily to correct distortion associated with perspective. For example when shooting a tall building from the ground your perspective will make it look like the top of the building is narrower than the bottom. With the tilt-shift lens you can calibrate its plane of view so that this distortion is corrected.
It can also aid with depth of view. When shooting at wide apertures, such as f/2.8 or f/4 a certain area of the image would be in full focus while there rest will not. By changing its angle once again, you can make everything be in full focus while taking advantage of wide aperture.
Many people, however, take this to the other extreme and change the plane of a tilt-shift lens to make almost everything out of focus except for a very narrow area. This creates an illusion that you are looking at toy miniatures, rather than real life objects.