What is focal length
A great photo is a combination of many components. The so-called technical ones are no less important than creativity and a sense of taste. This article will attempt to have one of them, focal length, explained simply.
The focal length is an optical property of a camera lens. It describes the distance between the lens and the image sensor. Usually, it is represented in millimeters and you can find it on the barrel, for example, 50mm, 85mm, 200mm, 18-55mm, and so on.
The focal length can give you an idea about the two following characteristics:
- how much of the scene that we see can this lens capture (angle of view)
- how large or small the captured objects will be (magnification)
Angle of view
Let’s try to understand how the focal length affects your photo. The correlation between it, the angle of view, and magnification is usually the following:
- shorter focal length — wider angle (larger areas can be captured) — lower magnification (smaller objects)
- longer focal length — narrower angle (smaller areas can be captured) — higher magnification (larger objects)
A few examples will help you better grasp the difference:
This photo was made using a lens with 28mm focal length. You can see most of the scene — a river, grass, stones, trees, and mountains.
This photo was made using a lens with 63mm focal length. You can see part of a room and several objects — a camera on a pile of books, something else in the background.
And this photo used a lens with 400mm focal length. You can see just a couple of enlarged objects — a butterfly on a flower. The rest of the scene is not visible.
So now you understand when you might need a lens with a shorter or longer focal length. And based on your creative plans you can select its type from the following typical focal ranges:
- Ultra wide angle (8mm to 24mm): the so-called, fish-eye lenses that have the widest viewing area and can capture the scene of up to 180 degrees around. However, they distort the image quite significantly.
- Standard wide angle (24mm to 35mm): most popular wide angle lenses that can have lots of objects in focus. These are great for landscapes, interiors, architecture, and group photos.
- Standard (35mm to 70mm): this type of lens most closely reproduces what we see with our eyes. They are most common and suitable for many purposes: portraits and landscapes, still and action photos.
- Telephoto (70mm to 400mm): used to shoot something from a large distance, for example, when making wildlife or sports photos, as well as portraits with a natural perspective.
Field of view
It will also be good to explain the meaning of another term you might face when talking about focal length — the field of view. While it sounds almost the same as the angle of view, there is still a difference between them.
While the angle is the characteristic of a lens only and always stays the same, the field of view takes into account the camera crop factor (difference between the size of a camera sensor and a 35mm film frame) as well as the distance to the object. Thus it is not fixed and can be different when you come closer or when you use a different body, but the same lens.
By the way, when you shoot a photo, remember that it is absolutely ok to edit your images. You can always resize them or adjust various settings, like white balance, contrast, and brightness. Сreativity doesn’t end when you press the shutter.