Camera Lenses Explained

Camera lenses

Camera Lenses

Next to the camera body, your camera lenses are the second most important part of your camera. Selecting the right lens (or lenses) is essential for getting the shots you want. Selecting a new camera lens requires time and research because you have to consider several factors; desired focal length, lens speed, compatibility with your camera, and budget.

In this article on Camera Lenses Explained, our goal is to arm you with the information you’ll need to choose the most suitable lens for your needs. At some point in time, you may find yourself shopping for a new lens for either practical or creative reasons. The first step in the process is to determine the variables you need to take into account when selecting your new lens.

Criteria for Selecting Camera Lenses

You need to take several factors into consideration when selecting a camera lens;

  • Purpose (portraits, landscape, sports, architecture)
  • Focal Length
  • Speed (1.4, 2.8f, 4.5/f)
  • Format (Cropped APS-C or Full-Frame)
  • Quality
  • Features (image stabilization, silent autofocus)
  • Budget

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Lens Focal Length

The Focal length of a camera lens, usually represented in millimeters or mm, is a description of the lens, but is not a measurement of the actual length of the lens. Focal length is a calculation of the optical distance from the point where light rays converge to form an in-focus image of the subject to the digital sensor in the camera.

The focal length of a lens is determined when the lens is focused at infinity. It basically tells us the angle of view, or how much of a scene will be captured, and the magnification (how large elements will be in the image). Longer focal lengths have a narrower angle of view and higher magnification. Shorter the focal lengths offer a wider angle of view and the lower or smaller the magnification.

Here are five apertures and their most common use;

  • 17mm – Extreme Wide Angle (Architectural and landscape photography)
  • 21-35mm – Wide Angle – (Landscape photography)
  • 35-70mm – Normal Zoom (everyday photography)
  • 70-135mm – Telephoto Zoom (Portraits)
  • 135-300mm – Telephoto (Wildlife, Sports, and Bird photography)
Lens focal length

Camera Lens Types

You need to familiarize yourself with are the various types of lenses available for your camera and the various definitions. Before we go any further, we’re assuming you have or plan to purchase a digital camera the accommodates removable interchangeable lenses. There are five general categories of camera lenses;

Prime Lens

Prime Lens

A prime lens has a single focal length. They are smaller and lighter than other lens. The most popular focal length is 50mm, which is supposed to be a close match to the magnification of the human eye. Prime don’t zoom in and out due to their fixed focal length. But they produce sharper high quality images than zoom lenses.

Zoom Lens

Zoom Lens

Unlike a prime lens with a fixed focal length, zoom lenses have a variable focal length that can be adjusted. Some of the most popular zoom lens focal length ranges are 24-70mm and 24-85mm.

Wide-angle zoom lenses are usually 14-24mm and 16-35mm. Telephoto zoom lenses are typically 70-200mm.

Telephoto Lens

Telephoto Lens

A telephoto lens has a long reach, which allows you to shoot a subject that is far away. A lens is considered telephoto if it has a focal length of at least 60mm. Telephoto lenses come in a number of focal lengths from medium telephoto (70-200mm) to super telephoto (longer than 300mm). These lenses can be either zoom or prime lenses. Telephoto lenses make your subject appear closer to your camera and they help emphasize a blurred background.

Wide Angle Lens

Wide angle lens

Similar to a Prime lens, a Wide Angle lens has a fixed focal length. These lenses have a short focal length (usually around 35mm) and a wide field of view. Ultra-wide angle lens are about 24mm or wider. Wide-angle lenses allow your camera to capture more of the scene than a normal lens can and are ideal for landscape, real estate, and interior photography

Macro Lens

Macro lens

A macro lens is for extremely close focusing distances and are capable of taking highly detailed images of tiny microscopic sized subjects like flowers, insects, products, jewellery, coins, and wildlife. Macro lenses allow you to focus extremely close to your subject so it appears large in the viewfinder and image. Another use for macro lenses is portraits (especially headshots and studio portraits). It is hard to beat the stunning sharpness of a macro lens.

Camera Lens Apertures

Lens Aperture

Another factor to take into consideration is the aperture. There are several different types of camera lens available for a wide range of uses. Lenses are identified by two primary parameters; the maximum aperture and focal length. Shorter focal length prime lenses have maximum apertures ranging from approximately f/1.2 to f/2.8. Telephoto lenses often have a maximum aperture of f/2.8 to f/5.6.

Costlier high-end zoom lenses maintain the same maximum aperture setting throughout their focal length range, while less expensive zoom lenses use a variable aperture range. For example, a lens with an aperture range of “f/3.5 – f/5.6” will be noted on the actual lens barrel as “1:3.5-5.6”. Lens kits sold with many consumer DSLR and compact system cameras often have a maximum aperture of f/3.5-5.6.

Full-frame vs APS-C Cameras

Yet another critical factor you need to consider when shopping for a lens is the camera sensor size. Most of the consumer DSLR cameras costing under $1,200 use what is known as a cropped or APS-C sensor measuring approximately 22x15mm. Higher end professional DSLR cameras use a full-frame sensor that is the same size as 35mm film measuring 36x24mm. Before you go shopping for a new lens, check the specifications of your camera to determine whether you have an APS-C or full-frame sensor.

Lens Selection based on Sensor Size

Once you know what kind of sensor you have (full-frame or cropped), you can start shopping for the correct lens. Most lenses fall into two categories;

  • Camera Lenses for Full-Frame sensor cameras
  • Camera Lenses for Crop Frame sensors cameras

Lenses are made specifically for full-frame sensors or crop sensor cameras. Crop frame sensor lenses are designed specifically to match the smaller sensor size inside the camera. If your camera has a cropped sensor, you can use both full-frame and cropped frame lenses. However, if you have a full-frame sensor camera, you don’t want to use a lens for crop-frame cameras. Full-frame cameras should only use lenses designed for full-frame cameras.

Identifying Full-Frame vs Cropped Sensor Cameras

So how do you tell the difference between a full-frame sensor camera and a camera with a cropped sensor? Lens manufacturers label their APS-C format SLR lenses as follows:

  • Canon (EF-S)
  • Nikon (DX)
  • Sony (DT)
  • Tamron (Di II)
  • Pentax (DA)
  • Sigma (DC)
  • Tokina (DX)

Nikon Full-Frame Cameras

Nikon refers to their full-frame image sensor format cameras and lenses as their FX Series. Current full-frame Nikon camera models are; Nikon D750, Nikon D810, Nikon D850, Nikon D5.

Nikon Crop Sensor Cameras

Nikon refers to their crop sensor DSLR cameras and lenses as their DX Series. Current cropped sensor Nikon camera models are; Nikon D3200, Nikon D3300, Nikon D5200, Nikon D3400, Nikon D5300, Nikon D5600, Nikon D5500, Nikon D7100, Nikon D7200, Nikon D7500.

Canon Full-Frame Cameras

Canon refers to their full-frame image sensor format cameras and lenses as their EF Series. Current full-frame Canon camera models are; Canon EOS 6D, Canon EOS 6D Mark II, Canon EOS 5D Mark III, Canon EOS 5D Mark IV, Canon EOS 5DS, Canon EOS-1D X Mark II, Canon EOS-1D X.

Canon Crop Sensor Cameras

Canon refers to their crop image sensor format cameras and lenses as their EF-S Series. Current cropped sensor Canon camera models are; Canon EOS Rebel SL1, Canon EOS Rebel T5, Canon EOS Rebel T6, Canon EOS Rebel T6s, Canon EOS Rebel T5i, Canon EOS Rebel T6i, Canon EOS Rebel T7i, Canon EOS Rebel SL2, Canon EOS 80D, Canon EOS 77D, Canon EOS 70D, Canon EOS 7D Mark II, Canon EOS 6D, Canon EOS 6D Mark II.

Image Stabilization (IS)

Nothing ruins an image more than a blurry image resulting from camera shake. Camera shake is particularly problematic at slower shutter speeds or with longer focal length lenses (telephoto or zoom). Image Stabilisation (abbreviated ‘IS’) compensates for camera or lens movement and will help you to achieve sharper images at slower shutter speeds.

Some cameras have image stabilization built-in, while others use IS in the lens. Image Stabilization in the lens works by using electromagnets to move internal glass elements. When you turn on image stabilization, those electromagnets are activated to create a floating spring-like suspension system so the glass can absorb camera shake and make your images sharper. Each manufacturer has its own definition for image stabilization;

  • Canon (IS) Image Stabilization
  • Nikkor (VR) Vibration reduction
  • Sigma (OS) Optical Stability
  • Tamron (VC) Vibration Correction
  • Fujifilm | Panasonic | Samsung (OIS) Optical Image Stabilization

Image stabilization is available in a wide range of different lenses, but it’s particularly effective with longer focal length lenses because images taken with longer lenses require faster shutter speeds to keep them sharp.

Lens Mounts and Third Party Lenses

Each camera manufacturer uses its own proprietary lens mount that we refer to as first-party lenses.  This means camera lenses cannot be swapped with different brands; a Nikon lens won’t fit on a Canon body. Other manufactures, referred to as third-party, make lenses to fit different mounts on multiple brands. Third party lens manufacturers include Zeiss, Sigma, Tamron, Tokina, Meyer-Optik Gorlitz, Rokinon, IRIX, Lensbaby, Samyang, Venus Optics, and Voigtlander Nokton.

Lens Quality

Some lens manufacturers offer different qualities of camera lenses. When we talk about a higher quality lens, we usually mean the glass elements used in the construction of the lens are of a higher grade, resulting superior quality images. Higher quality lenses are usually weather sealed and as you might have guessed, more expensive. Canon “L” lenses (Canon Luxury Lenses) can be easily identified by a red ring or white body. Nikkor lenses have “ED” on the lens barrel to signify the “Extra Low Dispersion” glass used in the lens.

Putting it all Together

The pictures you take, or the pictures you plan on taking, will determine which lens is right for you. So first decide if you need a lens for photographing picturesque landscapes, travel, sports, close-up shots, capturing wildlife, a lens for wedding photography, or even for a traditional portrait.

Next, check for lens mounting compatibility and compatibility with the sensor in your camera. Decide whether you need a fast lens and what maximum aperture you desire. Decide whether you need a higher quality lens and what extra features you need (image stabilization, autofocus, weatherproof, etc.).

Camera lenses will be a good investment because lenses usually last longer than camera bodies and are less likely to become obsolete. So don’t be afraid to spend a little extra for a quality lens. Those of you who are just starting your journey in capturing photography with professional-level cameras – moving away from the phones or point and shoots – make sure you read up on our top camera lenses for beginners.


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