The lens is undeniably crucial for a camera. Without this component, obtaining an image is simply impossible. The lens frames the scene and determines what will be available to you, what will be in focus, and what won’t be. Depending on the focal length, you’ll get different images.
Based on focal length, there are two main groups:
Zoom lenses;
Models with a fixed focal length (also known as primes).
What exactly is meant by focal length? It refers to the distance from the surface of the sensor, where the image appears, to the center of the lens (optical, which doesn’t always coincide with the physical center). This interval is measured in millimeters. A longer focal length reduces the angle of view, which is crucial to consider.
Furthermore, based on focal length, lenses can be divided into three groups:
Short or wide-angle lenses;
Normal lenses;
Long or telephoto lenses.
Wide-angle lenses are convenient for emphasizing perspective and space in the frame. They are excellent for capturing landscapes and scenes that encompass a wide angle of view. These models can be ultra-wide-angle or simply wide-angle. There’s also an intermediate option known as a moderately wide-angle lens.
What do these different options provide? Normal lenses don’t imply any particular effect; they simply show what the human eye typically sees. They are a good choice for portrait photography. As for telephoto lenses, they provide a magnifying effect. As a result, the frame composition becomes very tight, and the angle of view captured is too small. Essentially, they are ideal for wildlife photography (shooting animals from a distance) and any subject that can’t be approached closely for various reasons.
Focal length not only affects perspective but also plays a crucial role in displaying the distance between elements, giving the image a sense of volume. Telephoto lenses compress perspectives, reducing the distance between objects and separating them from the surroundings.
The diagram below shows how the angle of view changes depending on the focal length: as the focal length increases, the angle narrows.
Additionally, don’t forget about the crop factor. The standard frame size is 35mm. These are the so-called full-frame cameras, which are among the most expensive models. If you’re buying a camera with a sensor smaller than the specified frame, it will have a crop factor other than one. To understand the actual focal length, you need to multiply this factor by the lens’s focal length.