How to Choose a Camera Lens

Criteria s for Choosing a Camera Lens

Camera lens options are many and picking one can be more difficult than anticipated. However, knowing the right things to look for when making a lens choice can reduce the lens options from thousands to mere tens. Here are some important criterias to consider when making a lens choice.

• Lens Mounts

The first thing to know about lenses is that lenses can only be attached to cameras through an interface called lens mounts(1). Also, note that lens mounts are found on both cameras and the lens itself. 

Cameras can be primarily differentiated by brand, design, and sensor sizes. Most brands create their digital cameras in either DSLR or mirrorless designs, which is irrespective of the sensor size in the cameras.

These camera classifications are important to lens choice because every camera type, class, and brand uses a unique lens mount. For example, a mirrorless, MFT(micro four-thirds) sensor Panasonic camera’s mount is different from a full-frame DSLR Sony camera’s mount. Basically, the difference in the two camera types implies that the same lens can’t work for both cameras, and this translates to all the different camera brands available.  

The good news is that every camera brand produce suitable lenses for their different cameras. In addition, some third-party producers also make lenses for different camera brands. To make choosing a compatible lens for your camera easier, lenses carry nomenclatures that signify the model(s) of camera they are compatible with. Another option is to use an adapter (helps with connecting different lens mounts). Adapters are only advised as a last option because they also have limits, and are not guaranteed to work. 

The most important part of knowing how to choose the right lens for your camera is choosing the right lens mount because every other feature of the lens is hinged on the lens being compatible with a camera. 

• Focal Length

Another important criteria to choosing the right lens is the focal length of a lens. The focal length of a lens determines the type and class of the lens. These differences also influence the best use cases of individual lenses. 

There are two types of lenses. Lenses with fixed focal lengths (Prime lenses) and those with variable focal lengths (zoom lenses). All things being equal, prime lenses produce better images than zoom lenses because their efficiency is concentrated to a single focal length. On the flip side, zoom lenses can work at different focal lengths which is quite useful for covering different distances without actually moving the camera. 

Zoom lenses and prime lenses are further classified based on the focal length they can effectively work in. Here are the classes of lenses based on operating focal length.

• Wide-angle

These lenses provide users with the largest viewing angle available. Their base of operation is at the lower end of the focal length spectrum. Wide-angle lenses can be from 8mm to 35mm with the widest FOV being the 8mm. In fact, at the 8mm focal length, the lens will be experiencing extreme distortion, resulting in what is known as fish-eye lenses. 

• Standard lenses 

These are lenses ranging from 35mm to 50mm. They are the lens favored for filming majorly because the FOV is close to that of the human eye. Standard lenses, as their name implies, are good for general videography. 

• Telephoto lenses

These are lenses with focal lengths above 80mm. They are specialized at viewing distant objects. Telephoto lenses can reach focal lengths over 600mm. Basically, the higher the focal length, the more distance the lens can cover, and the smaller the field of view (FOV). 

Also read: Best focal length for video

• Aperture

The lens aperture(2) is another primary lens feature that determines the amount of light the camera’s sensor is exposed to. The aperture works in collaboration with the shutter. The impact of the aperture on lens choice lies primarily in the aperture range and the maximum aperture. 

Lens apertures are represented with “f” followed by a number. E.g. f22 or f/22. With aperture, higher numbers mean smaller diaphragm openings while smaller numbers mean larger diaphragm openings. An f/1.2 aperture is larger than an f/22 aperture. 

The aperture range comes in handy when a user is trying to change an image’s field depth. The depth of field of an image, in simple terms, refers to the area of the image, in focus. Wide aperture ranges give more room for control over the depth of field. Generally, smaller f-numbers result in smaller depth of field while larger f-numbers result in a bigger depth of field.

The lens mount is the foundation for every lens feature, without which the lens can not function.

Now, about a lens’s maximum aperture, lenses with wider maximum aperture are usually better because they can work with little lighting. Furthermore, good max aperture provides better subject isolation in an image frame. For example, a lens with a maximum aperture of f/1.2 will offer better subject isolation and be able to work with little lighting.

Also read: How to clean a camera lens without a cleaning kit