Understanding the Different Types of Lenses

Photography without lenses is possible, but rather impractical. At its most basic we can identify a camera as a separated space with a small hole in one side which allows like to converge and project onto a surface, this is called a camera obscura. However, these pin-hole cameras produce soft pictures with little detail. That’s where lenses come in. By placing a single, or a series of glass elements in said hole, the light can now be focused to reach the surface with greater clarity. The movement of the glass elements can be interpreted as the lens’ ability to focus.

There are many types of camera lenses. The main difference between lens types is their focal length. Prime lenses have a fixed focal length, and contain few glass elements making them cheaper and sharper with wider maximum apertures. Prime lenses require the photographer to move the camera to recompose an image. Zoom lenses are simply multiple glass elements stacked inside a lens casing that also has the ability to shift the elements back and forth in order to adjust the focal length between lens and projected surface (usually photographic film or an image sensor). They are more complex, contain much more glass and are difficult to produce cheaply without issues like chromatic aberration (colour fringing around subjects).

Lenses are first and foremost, categorised into focal length, maximum aperture rating and also on additional attributes such as their ability to focus closely or containing image stabilisation. Let’s take a look at some ideal uses for each focal length and then clear up the jargon with some simple descriptions.

Focal length: The focal length of a lens is the determination of the range between the image sensor/ focal point to the center of the given lens. The lens predetermines the extent of image magnification from a position and the angle of view.

Aperture: An aperture is the size of an opening. In photography this is measured in f/stops. The lower the number (wider aperture) the more light it lets through the lens. The higher the number (narrower aperture) the less light it lets through the lens. F/stops are measured at full stops, half stops and even one third stops. An aperture of f/2.8 will produce twice as much sunlight than f/4 because it is a full stop wider.

Depth of field: The depth of field refers to how much of the scene is in focus once correct lens focusing has been achieved. This is determined by two things: the aperture and the focal length of the lens. A narrower aperture (e.g. f/16) will increase the depth of field, meaning more of the scene front-to-back is in sharp relief. A longer focal length (e.g. 100mm) will reduce the depth of field.

Image stabilisation: The glass elements in the lens are controlled by a motor which notices tiny shifts in camera movement and keeps things steady in the viewfinder/rear LCD screen. New camera bodies are now using in-built stabilisation where the image sensor itself is stabilised, instead of the lens stabilising the image. This can make lenses smaller, and lighter.

Focal length: 50mm

Ideal usage: documentary, street and portrait photography

It’s supposed that the human eye has an approximate focal length of around 50mm, that’s why the 50mm lens is referred to as ‘standard’ or ‘normal’. This direct lens-to-eye comparison serves as a reference point against which pincushion and barrel distortion as measured. That is, the apparent bending, and distorting, of a scene as a result of a change in focal length.

The ‘nifty fifty’ is an excellent lens for beginners because they are generally very sharp, light, small and cheap. Professional models don’t differ much, but often have wider maximum apertures, image stabilisation and improved optical clarity.

Key advantages

• Suitable for lowlight photography

• Lightweight device

• Higher quality image production

• Good beginner’s choice

Focal length: any lens that has a focal length range, i.e. 11-16mm, 18-200mm or 100-400mm

Ideal usage: travel, wedding, portrait, wildlife, reportage

A zoom lens affords the photographer the option to alter composition without having to move the camera. This is particularly helpful when changing the shooting position is difficult or impossible, such as shooting a seascape from a cliff, capturing a wedding, or photographing wildlife. They are useful for travel photography because it means the photographer only needs to carry a single lens, rather than a set of fixed, prime lenses.

More expensive options have a constant aperture, such as f/2.8 which means it can shoot as wide as f/2.8 no matter how far zoomed in or out the lens is. However, more affordable versions have an aperture range, for example f/4.5-5.6 as the lens is zoomed through the focal length range. That means one or two stops less light coming through the lens, and therefore would require either a slower shutter speed, higher ISO or increased light.

Key advantages

• A photographer can take different focal length shots while maintaining the same shooting position

• The lens is suitable for when changing lenses is difficult. For example, a wedding, in dusty/sandy/wet locations, or when travelling and want to carry minimal gear

• Cuts the stress of readjusting positions before taking subsequent pictures

Focal length: 70-600mm

Ideal usage: sport, wildlife, action, motorsports, portraiture

Longer focal length lenses, telephoto lenses, are used to get perceptibly close to subjects while keeping the camera far away. This is especially useful for wildlife photography because it allows the photographer to capture animals behaving naturally, without disturbance. A sports photographer will find telephoto lenses crucial to capturing action from across a pitch or in an arena, whilst ensuring the subject remains large and the focus point in the composition. Some portrait photographers also favour telephoto lenses because of the perspective compression they inherently have. They appear to ‘flatten’ the subject’s features and help isolate subjects from the background, helping them stand out in an image. The longer the focal length, the shallower the depth of field, and because of this telephoto lenses often create beautiful bokeh, (out of focus background/foreground elements) which improve some imagery. Good telephotos are often heavy, big and cumbersome to carry, that’s why they’re often used in conjunction with monopods and tripods.

Key advantages

• Photographers do not need to move around; they can take shots while maintaining the same position

• Rids unwanted details by creating a blur in the background surrounding images but produces a high-quality clear picture of the subject

• Reduces the perceived distance to make the image look closer than it should be

• Lens’ with image stabilisation helps to automatically reduce vibration and shake inside the lens, preventing blurring

Focal length: 45-200mm

Ideal usage: detailed Photography (nature shots, wedding detail, products)

A true macro lens reproduces the subject on the image sensor at life size, by which we mean the size a subject takes up in real life, will be how much space it takes up on the image sensor at the minimum focusing distance. The reproduction ratio is often referred to as 1:1. Other lenses with ‘macro’ capabilities are not true macro lenses and often have reproduction ratios of 1:2-1:4 which means subjects only take up half or a quarter of their actual size, on the image sensor. Whilst some macro lenses go the other way, making them appear larger for even more detail, such as 2:1 or 5:1. The greater the reproduction ratio, the higher the magnification, and therefore the more detail can be recorded by the camera.

Key advantages

• Excellent image sharpness and quality

• Close-focusing means small subjects are rendered with high level of detail

• Also good as portrait lenses

• Good for product photography in the studio or for small wildlife on location

Focal length: 24-35mm

Ideal usage: landscape, architectural, and interior photography

A wide-angle lens typically shows a wider field of view than the human eye can. Therefore any lens below 50mm focal length is generally considered wide. These types of lenses are good for any photographic genre, despite the myths associated with this kind of lens. But generally, photographers use wide-angle lenses to fit more of the scene in and provide context to subjects. They can suffer from pincushion distortion where straight edges appear to bow towards the centre of the frame, but rectilinear lenses correct this bending. It’s important to realise though, that the closer to the edge of the frame one puts the subject, and the wider the lens, the more warped the subject will appear. Wide-angle lenses are usually smaller than most lenses because of the shorter focal length, and are lighter than other lenses, too, making it easier to travel with them. They also have an inherent ability to increase depth of field in an image, so things will appear sharp front-to-back when correctly focused.

Key advantages

• Pictures contain more depth and contextual information due to wider field of view

• It provides a greater depth of field for sharper front-to-back images

• Lightweight lenses in smaller packages make them easier to carry

• Great for a wide range of subjects

Focal length: 8-24mm

Ideal usage: sports, landscape, advanced science, and architectural photography

Otherwise known as super wide-angle, ultra wide-angle lenses compromise a small range of lenses that are known for their extremely wide field of view. These lenses can also suffer with pincushion distortion with straight edges appearing bent, but like wide-angle lenses, there are rectilinear versions available to keep lines straight. It is a common misconception that all ultra wide-angle lenses are fisheye. Although fisheye lenses do fall under the ultra wide-angle category, they very specifically attempt to include as wide a field of view as possible, often 180 degrees or greater. Their front elements bulge out far in front of the lens casing and never give straight lines in a scene. Ultra wide-angle lenses in general suffer from bulging of front glass elements, which can make it difficult for photographers who wish to use filtration - with additional adapters sometimes required. They’re fantastic for night sky photography and in situations where maximum field of view is desirable, for example in scientific, architectural or landscape photography.

Key advantages

• It is useful for scientific photography, to determine solar radiation and observe plant canopy geometry

• Wide field of view makes them great for landscapes

• Perfect for abstract photography

• Useful for astrophotography

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With a few myths dispelled, and some technical guidance outlined in this article, you’ll hopefully now have a better understanding of what each type of lens does, and how to implement them in your kit bag. Of course, after snapping with your preferred lens, you will need an excellent photo editor to give your pictures a final perfect blend. Try the guide Photo Editor by Movavi; it arguably has all the necessary components to make your pictures look great.