Everything to Know About Camera Lenses

Camera lenses are arguably the most important part of your camera setup. They control the image projected onto your imaging sensor, acting like your eyes into the world of photography and ultimately shaping the photos you take.

A new lens offers such amazing potential and possibility, but choosing the best type of lens for your camera can be difficult sometimes. They’re a real investment and it’s worth doing your research.


This camera lens guide brings together the main things you should consider when getting a camera lens:

  • Lens mount
  • Focal length
  • Aperture
  • Format
  • Creative lenses

Ensure the camera lens fits

Firstly, it’s important to ensure the lens is compatible with your camera. Most of the major brands apply their own lens mounts to their cameras, meaning that a Canon lens won’t work with your Nikon DSLR.

Check the camera lens specs to make sure it fits. An ill-fitting lens, even if it’s only ever so slightly larger, can cause adverse effects to both the lens and the camera.

Get the right focal length

A key thing to consider is the focal length, defined as the distance between the lens and the image sensor when the subject is in focus, measured in millimetres by the range between the minimum and maximum focal lengths.

The smaller the focal length measurement, the wider the angle of view will be. For example, an 18mm focal length lens will produce a wide shot while a 200mm lens will produce a much closer shot.

Focal Length (35mm equivalent) Lens
<20mm Extreme wide angle
21-35mm Wide angle
35-70mm Normal
70-135mm Telephoto
135-300mm Extreme telephoto

Did you know? The human eye sees at roughly a 50mm focal length.

If you’re after a beautiful landscape shot, you’ll prefer a wide-angle/low focal length lens. If you’re after portraits or a close-up of a bird, the small angle/high focal length lens will suit you better.


Be sure about aperture

Aperture is often displayed as, say, f/2.8. This number refers to the maximum amount of light the lens can gather. Lenses with larger maximum apertures (but the lower numbers) are capable of gathering more light.

An f/1.8 lens is able to use more light, which means it can be used in lower-light situations without having to use a flash, and is capable of producing a shallower depth of field.

Some zoom lenses have a variable aperture number and changes depending on focal length. Take an 18-200mm, f/3.5-5.6 lens. Although the maximum aperture is f/3.5 at 18 mm, it would change to f/5.6 with the zoom at 200 mm.

Photographers who like to take night shots should pay special attention to the lens aperture and whether they’re designed for lower-light situations.


At this point, if you’re wondering why we don’t all just use 15-400mm, f/1.8 lenses, the two main reasons are size and price. A lens of this magnitude would be massive and cost a fortune.

Camera Lens Format – DX v FX

Displayed on the lens is either the DX or FX format symbol. This describes the sensor size that the lens is designed to work with.

While FX format lenses work with full frame size sensors, DX lenses will work only with the smaller of your camera’s sensors. Essentially, this means that a DX format lens may crop your photo due to the differing size sensors of the camera. Read more about the differences between DX and FX here.

Creative lenses

Beyond the standard zoom lenses lies a treasure trove of creative lenses you might be interested in.

One popular example is the fisheye lens, which produce a strong visual distortion to generate a hemispherical image. Its circular angle of view produces an image similar to the peepholes commonly found on front doors.

Tilt-shift lenses allow you to extend or shorten the depth of focus of what you’re photographing (see picture below). Architects and artists who deal with miniatures, in particular, love this type of lens.

There are even 3D lenses to really get your creative juices flowing.

Next steps

Whether you’re a traveller looking for an affordable, all-rounder lens or a landscape photographer on the hunt for a wide-angle lens with a shallow depth of field, there are so many camera lenses out there.

The more you know about lenses the better. Here at Camera House, we offer a great selection of lenses and all the necessary accessories, so feel free to browse our range with your newfound knowledge.

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