Trying to understand focal length in photography? Focal length refers to two things: the angle of view and the magnification. Learn more about focal length, discover tips, and find the right lens for your next shoot.
In this article, we’ll cover:
What Is Lens Focal Length?
What is focal length in photography? Focal length refers to two things: the angle of view and the magnification. The former refers to how much of the scene will be captured. The latter lets you know how large the individual elements will appear in the frame. Focal length is important in photography because it determines what your pictures will look like.
The focal length is generally represented by millimeters on the lens. It also acts as a shorthand for describing a lens. The focal length of a lens is determined by the optical distance between the focal plane and the center of the element when the lens is focused at infinity.
If you are shooting on an analog camera, the focal plane is the piece of film. If you are using a digital camera, that focal plane is the camera’s digital sensor.
Lenses with shorter focal lengths will have a wider field of view. Lenses with longer focal lengths will have a narrower field of view, but increased magnification.
How to Find and Determine Focal Length
Not sure what focal length your camera lens might be? Luckily, you don’t have to make any tricky optical measurements to figure it out.
Lens manufacturers include the focal length of a lens within its name and include it somewhere on the lens barrel.
Canon’s mirrorless 35mm lens is officially called the RF35mm F1.8 Macro IS STM lens. Here’s what all of those letters and numbers mean.
- RF35mm: This refers to the lens mount type and the focal length. The focal length is easy to spot because it will be followed by “mm” to indicate millimeters.
- F1.8: This tells you that the lens has a maximum aperture of 1.8. The aperture is how much light the lens can let in when you make your exposures.
- Macro IS STM: Macro means that the lens can be used to shoot details extremely close up. IS means it has built-in image stabilization. STM is an abbreviation for stepping motor technology, which is what makes the lens focus smoothly and quietly.
On the barrel of this particular lens you will find the numbers 0.17m/0.56ft – ∞. These markings refer to the distance that the lens will be able to focus in AF mode.
This online simulator is a great visual tool for focal length comparison. Play around to see how lenses with different focal lengths will capture the same scene.
Types of Camera Lenses
Camera lenses are divided into categories that are defined by focal lengths. These are the basic types of camera lenses and focal lengths they generally cover:
- Fisheye: 4mm-14mm
- Wide-angle: 14mm-35mm
- Standard: 35mm-85mm
- Short telephoto: 85mm-135mm
- Medium telephoto: 135mm-300mm
- Super telephoto: 300mm +
Comparing Camera Lenses
Choosing which lens and what focal lengths you are going to use when taking pictures is one of the most important decisions you can make as a photographer.
The camera focal length determines what is going to be in frame, but it also determines just how close you will be getting to your subjects when you’re taking the picture.
Here’s a quick guide to figuring out the differences between popular types of camera lenses.
Prime Lenses vs Zoom Lenses
Prime lenses only offer a single focal length, meaning you will need to physically move your body if you want a different perspective.
Popular focal lengths for prime lenses include 35mm, 50mm, 85mm, but they are available with super-wide fisheye perspectives and super telephoto lengths, too.
Prime lenses tend to offer wider maximum apertures, which is why photographers refer to them as being fast. The technology inside of a prime lens is quite simple compared to a zoom lens, which makes them more affordable.
Zoom lenses offer a range of focal lengths within a single lens. A 24-70mm is a classic camera focal length for a zoom lens and a popular choice that comes bundled with a camera body.
Zoom lenses can be more convenient and versatile than a prime lens because you can cover a wider field of view without having to change the lens.
The technology inside of a zoom lens is more complicated, and the price of a standard zoom reflects that. Generally speaking, they also have maximum apertures that don’t open quite as wide as a prime lens.
Wide-Angle Lenses vs Telephoto Lenses
Wide-angle lenses are lenses that cover up to a 35mm field of view. This field of view is wider than the human eye and will increase your scope.
A wide-angle lens is a good choice for shooting sweeping landscapes, large group portraits, or for off-kilter street photography.
Lenses with a focal length that is below 24mm are sometimes called ultra-wide lenses and encompass fisheye lenses.
A telephoto lens refers to anything with a focal length of 85mm and above. These lenses produce a tighter field of view and mean that you can photograph subjects without getting super close.
Short telephoto lenses are popular choices for photographers capturing live music, weddings, and portraits. Medium telephoto lenses cover a range of 135mm-300mm and are an important lens choice for sports and bird photographers.
Super telephoto lenses are anything with a 300mm focus length and above. Lenses on cameras with such long focal lengths are typically only used by the pros.
This style of lens can regularly be spotted on the sidelines of sporting events or by photographers who specialize in photographing dangerous wildlife, where keeping your distance is crucial.
Telephoto lenses get more expensive and much heavier as the focal lengths increase to account for all the elements on the inside of the lens. Wide-angle and telephoto lenses are available as both prime or zoom lenses.
Short Focal Length vs Long Focal Length Lenses
Short focal length is an umbrella term to describe any lens that falls in the category of wide-angle or standard. A lens with a short focal length can include anything that falls between 4mm – 85mm.
Long focal lengths include all telephoto lenses—anything that captures a field of view that’s tighter than what the eye can see.
Short focal length lenses will give you a wider field of view, but offer less magnification of the subject. Long focal length lenses give you a narrower field of view, but magnify whatever is in the frame.
Long focal length lenses are popular choices for weddings, wildlife, or sports photography. Short focal length lenses are good for architecture, landscapes, street photography, or photojournalism.
Most photographers rely on a mixture of long and short focal lengths to capture images.
Choosing the Right Focal Length
Choosing a focal length is one of the most important decisions you can make as a photographer. There’s a reason that professional photographers have a collection of lenses at their disposal to make sure the focal length matches the moment.
Considering what you are shooting and where you will be working is an important first step. If you’re covering a massive concert at an outdoor venue, a telephoto zoom lens will help you grab detailed shots of the performers, but also shots of the general atmosphere.
If that same performer is doing an intimate night at a club, a prime lens with a fast aperture and a wider field of view might be a more appropriate option.
Headshot photographers generally use focal lengths of at least 85mm to capture flattering portraits of their subjects.
However, an environmental portrait photographer capturing an artist in their studio might want a wider field of view to help bring additional elements into the frame.
Types of Specialty Lenses
Certain photography styles call for a unique specialty lens. Here’s some of the unique properties of these lenses and reasons why a photographer might choose to use them.
Fisheye Lens
The fisheye lens offers a super-wide field of view that’s almost circular. A true fisheye lens has a field of view between 4-16mm. A fisheye lens will offer a super distorted view of the world.
It’s a popular choice with action sports photographers and portrait shooters looking to channel an early-90s aesthetic.
Wide-Angle Lens
Wide-angle lenses offer an ultra-wide view of the world, without the level of distortion found in a fisheye. A wide-angle lens can range from 16mm-35mm and is a good choice for photographing landscapes or group photos.
Standard Lens
These are the lenses that almost every photographer has in their kit. Standard lenses cover a focal length range of 35mm-85mm and can be a prime or zoom lens.
These lenses are versatile tools that are good for a variety of styles of photography. Standard lenses are a great choice for events, portraits, food photography, and still lifes.
Telephoto Lens
Telephoto lenses are anything with a focal length of about 85mm. Short telephoto lenses are a popular focal length for all styles of photographers because of their versatility.
These are a more specialized tool used by pros photographing major sporting events or out in nature capturing dangerous wildlife.
Practical Tips for Choosing Lenses
Choosing the right lens for your photography ultimately comes down to personal preference, but it can be useful to consider what you are shooting. It’s also important to consider how much you are willing to spend.
Lenses with longer focal lengths tend to be much more expensive, so before you buy consider your needs. There is absolutely no reason to break the bank on a super-telephoto lens if you’re primarily interested in portrait or still life photography.
If your passion lies in photographing weddings and corporate events, an ultra-wide fisheye lens won’t be very useful to you.
We recommend keeping it simple if you’re just getting started with photography. A standard 24-70mm zoom lens and a 50mm prime lens are a great place to begin your exploration with focal length.
License this cover image via Cacio Murilo and v_kulieva.
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