What is Focal Length and How Does it Affect Your Photos?

What Is Focal Length?

The focal length, which is frequently specified in millimeters (mm), is the essential description of a camera lens. It is calculated from the optical distance from the focal plane of the camera's digital sensor or 35mm film to the point where light rays converge to form a sharp image of an object, rather than being a measurement of the actual length of the lens. It is possible to determine a lens' focal length when it is focused to infinity.

Both, the magnification and the angle of view, or how much of the scene will be caught, depend on the focal length of the lens. Magnification increases and the field of view narrows as the focal length increases. More expansive angles of view and lower magnifications result in a shorter focal length.

How Does Focal Length Affect an Image?

Field of Views

The focal length affects how much of a scene is captured in a photograph. Shorter focal length wide-angle lenses provide a greater field of view in a single image. Lenses with a long focal length and a small field of view are referred to as telephoto lenses.

Perspective Compression

The focus length may also alter the perspective and scale of your images. A lens with a shorter focal length "expands" perspective, making it look as though things are farther away in your photo. Telephoto lenses, on the other hand, commonly group things together to "compress" perspective.


The amount of a scene that will fit into the image area of a particular size film depends on the focal length of the lens being used. An image that has a greater focal length is larger. The portion of a scene that will fit in the image area decreases as the image size increases. Just have a look at these images, which were taken at the same location with lenses of various focal lengths from the same camera position. Keep in mind that the focal length has a direct correlation with the size of the image. All other things being equal, doubling the focal length doubles the size of the image. Assume that you are photographing something from ten feet away using a 50mm lens. Switching to a 100mm lens now makes the thing appear twice as large.

Depth of Field

Long focal length lenses frequently feature tiny depths of field, allowing them to focus close-up on little objects—even those in the distance. Conversely, short focal length lenses have a greater depth of field, allowing them to focus on a wider variety of objects.


The blurriness and degradation of image quality that result from the vibration of depressing the shutter release are known as image shake. Your lens and camera will be more sensitive to even the smallest movement when using a lens with a long focal length and close perspective. A tripod can be used to reduce image shaking.

Suggested Focal Length Based on Type of Photography

With all the many kinds of lenses available on the market, getting started in photography can be a minefield.

Even a seasoned photographer may find it challenging to articulate the precise distinctions and purposes of each individual lens, but being more knowledgeable about a lens's capabilities, focal lengths, and applications can help you use it effectively in a variety of shooting situations.

Besides than understanding the different functions and purposes of lenses, one of the first steps in becoming a far better photographer is understanding what focal lengths to use based on the type of photography. Moreover, there is a time and place for every focal length of the lens, and it isn't simply about how much of the scene it captures. The focal length that isolates the subject, or hero, in your image and keeps out the distractions, or villains, is the optimal focal length.

Portraits Photography

If you are into taking portraits, the suggested lens type would be standard with a focal length of 35 mm – 85 mm. You could also opt for a short telephoto lens with a focal length of 85 mm – 135 mm. These focal lengths are flattering because they do not distort the subject's facial characteristics.

Street Photography

Standard and short telephoto lenses are also applicable for street photography with focal lengths of 35 mm – 85 mm and 85 mm – 135 mm, respectively. These focal lengths are great for taking pictures of streets and landmarks because it's wide enough to include all you need in the picture. It's great for candid pictures as well because the picture will make you feel as though you were there with the subject.

Architecture Photography

Architectural photography is frequently about capturing every last detail. So, if you are looking to capture the intricate details of picturesque architecture, we recommend a wide-angle lens with a focal length of 14 mm – 35 mm.

Landscape Photography

Photographers of landscapes frequently enjoy getting down low. However, everything that is close to the camera will be out of focus when utilizing a long focal length lens. You will need to focus stack your photographs or switch to a wide-angle lens if you require the foreground elements to be in focus. Scenic landscapes, similar to architecture, would require a wide-angle lens with a focal lens of 14 mm – 35 mm.

Wildlife Photography

Long focus lengths are required for wildlife photography since wild creatures typically won't allow you to approach them up close. Wildlife photographers who frequently capture images of distant animal species choose super-telephoto prime lenses, which typically have a starting focal length of roughly 600mm. The depth of field in these long-lens pictures is frequently rather shallow.

Sports Photography

Similar to wildlife, you can use a medium telephoto lens with a focal length of 135 mm+ for sports photography. However, for sports from a distance, consider using a super-telephoto lens with a 300 mm+ focal length.

In conclusion, you'll be better equipped to select the right focal length for your next assignment after you comprehend the practical mechanics of how focal length works in photography. Ready to upgrade your gear with the most appropriate focal lengths for your photography type?