What On Earth Is Focal Length?
The focal length in photography is determined as the distance between the lens and the image sensor when you are focusing on a specific subject. Most focal lengths are measured in millimetres ranging from as low as 18 mm to 100 mm. The focal length may just be a number but when it is translated into a picture, you will know how different focal lengths give a different effect or impact to your picture.
While many seem to complicate the idea, Lunamik likes to keep it simple for those just starting out. So first, just familiarise yourself how focal length should be visualised, it is good to remember that a short focal length will result in a wider field of view while a long focal length will mean a narrower field of view.
There are different kinds of focal lengths that are associated with the different kinds of lenses. Extreme wide angle lenses have a focal length of less than 21 mm. Wide angle lenses have a focal length range from 21 mm – 35 mm. The standard focal length for the normal lens is usually around 35 mm – 70 mm. Short/Medium Telephoto lens have a focal length of 70 mm – 135 mm. A telephoto lens has a focal length ranging from 135 mm – 500 mm.
Aside from the focal length, the sensor size is also a factor when you are adjusting your lenses. There is a handy camera lens calculator that lets you have an idea about the field of view in major consumer cameras available in the market.
You can experiment or check how the different focal lengths affect the overall impact of a photo by choosing one subject and using different kinds of cameras to see how each focal length is different from one another. By changing the focal length of the camera, you can also change the dynamics of the composition of the photo. In effect, it also affects the psychological values on how you will perceive the photos.
Wide angle lenses
Wide Angle lenses usually have the illusion that the subject is farther than you’d perceive it to be. The depth perception in this kind of lens is usually heavily exaggerated with an enhanced movement on the z-axis. A standard lens on the other hand closely shows how we actually perceive the subject. The angle of view of humans is measured at around 40o while the standard lens has an angle of 39.6O. Lastly for telephoto, the effect is usually opposite of the wide-angle lens and shows the subject to be compressed compared to its foreground objects. As an effect, distant objects seem to be closer and can become a complete blur.
By adjusting the focal length of your camera, you can actually create visual scenes and footages that give a different impact. Study how you want a particular video is portrayed and you can choose the kind of lens you want to use. The effect is usually influenced by the psychological vibe that you want to convey on your film. Lunamik encourages you to try to experiment some different lenses and see which one you prefer the most.