What is Focal Length in Cinematography?

Forget the technical definition of focal length, it’s unnecessary to understand it or practice cinematography.

In this video I explain only the useful features of focal length in cinematography and mainly how to exploit focal lengths for maximum impact:

The Angle of View

Lenses cut out parts of what’s in front of you, and only show a portion of it. You can actually measure the angle of it from the position of the camera, and you have what is called the angle of view.

Want to get a tighter shot? There are two ways. You can either walk closer, or you can get a different lens with a smaller angle of view.

The Focal Length

The number we give lenses to represent the angle of view, is the focal length. It does have a technical definition as well, but that definition is in no way useful to cinematographers. If you want to know what it is, wikipedia is a good place. For those who don’t want to waste time on unnecessary theory, all you have to know is the angle of view is always, always dependent on the size of the sensor.

A larger sensor will give you a wider angle of view for the same lens, while a smaller sensor will give you a tighter angle of view.

Since sensor sizes are all over the place nowadays, if you put the same lens on different cameras, you might get different angles of view. A Sony a7S II will be different from the Panasonic GH5 will be different from a Red Raven will be different from an Arri Alexa, becaue their sensor lengths are all different.

So what we really need is a gold standard. Some starting point from which to calculate the rest if we ever need to. I’ve written an extensive article on the 35mm equivalent and crop factors if you want to learn more, I’ve decided the 35mm full frame format is the best gold standard we have today. It’s been around long enough and is most relevant for cinematography. By 35mm full frame I’m talking about 135 or a sensor measuring exactly 36mm x 24mm. The Nikon D4, D850, Sony a7S II, a7R III and so on are all full frame sensors.

Wide Angle, Normal and Telephoto

So let’s say I want a wide angle of view. To get that I use what is very loosely called a wide angle lens. Let’s just say we’re using a 24mm lens for this example. What’s this “24mm”? It’s just a name. It’s not 24 degrees, but it represents a certain angle of view on a 35mm full frame sensor, and we call it wide angle, through tradition.

Focal lengths are written as XXmm, where XX is a number (single digit to as high as four digits)

Any number smaller than this is wider. So the wider you need to go, the smaller this number gets. It’s always in millimeters and is written on the front and sides of your lenses. This number is called the focal length.

The higher the number, the smaller the angle of view. Of course, this is only true if you’re using the same sensor for comparison. E.g., a 24mm lens on a full frame camera is wide, but the same lens on a Micro Four Thirds sensor would be the equivalent to a 48mm lens. If this is confusing to you, then please read my article on the crop factor and the 35mm equivalent. Now here’s the thing, a 48mm is not considered wide. In fact, in the full frame world, a 50mm lens is considered normal, by tradition.

So we have a range of lenses that go from super wide to wide angle. Through tradition, wides roughly end at about 35mm. From 35mm to about 70mm we have the normal range. And finally, anything above 70mm could be considered telephoto. When it goes beyond 200mm, people also call it super-telephoto. Beyond 2000mm, you’re looking at a telescope.

If you want to shoot a wide vista, say the grand canyon, you might love the ultra wide angle focal lengths. If you want to shoot mid shots or documentary-style, you might like the normal range, if you want to flatter your star, then pick a telephoto lens.

The Emotional Aspect

The angle of view of a lens is just one function of the focal length. Different focal lengths have different emotional impacts. If you shoot a closeup of a person with a 24mm, the emotional response will be totally different when compared to a 50mm, and that will be different to a 135mm. The more telephoto you go, the more the background comes closer. Wide angles make things appear more spacious than it actually is. Are you in a small room? Then use a wide angle lens to make it look bigger. YouTubers do this all the time to make their rooms look bigger.

When you use a wide angle lens, the faces tend to distort outwards, making them rounder. The nose looks bigger and more pronounced. Some cinematographers love the wide angle look. The most famous of them today being Emmanuel Lubezki. Check out my video on his cinematography:

Some cinematographers prefer the normal range, Roger Deakins is a great example. He loves a 32mm lens on the Super 35mm format, which would roughly be a 45mm lens on a full frame 35mm sensor. Watch my video on his cinematography:

A good example of consistent telephoto use would be Ridley Scott’s films, and many TV shows running today. They make the stars look good, so why not?

The Takeaway – the important things you need to know about focal lengths

So what do you really need to know about focal lengths when you’re a beginner? Just three things:

  1. Focal lengths by itself don’t really mean anything. You also need to know the size of the sensor it’s going to be used for.

  2. The smaller the number the wider it gets and more spacious everything looks. The larger the number the tighter it gets and more compressed or restricted everything looks.

  3. Most important. Different focal lengths tell a story differently. The entire emotional impact changes for the same sized shot with different focal lenses, so choosing the right focal length is hugely a matter of personal taste. Movies like Amelie have used super wides but still have faces look great, because the director knew when to stop. There’s a lot of personal aesthetics involved here.

How do you know which one you should pick?

Here’s a simple trick. Have you clicked photos? Go back to all the photos you have clicked, and see if you’ve cropped them mostly. If you’ve cropped most of your photos then you probably are not a wide-angle person. On the other hand, do you feel most motivated with a wide angle lens? Then maybe that’s the focal length range you should start out with.

The traditional range runs like this:

  1. 14mm is ultra wide.
  2. 24mm is wide.
  3. 35mm is between normal and wide, and many consider this to be close to what the eye sees.
  4. 50mm is normal, which means the face is not distorted, and it gives you the most unbiased look, if you will.
  5. 85mm is portrait, and flatters your subject. Telephoto distorts the other way, makes faces look thinner. Anything more will flatter them even more, but you are hit with the practical limits of space in cinematography. You have to move further back but there might not be room.
  6. If you need to shoot wildlife or birds, then go telephoto or even super-telephoto.

Primes or Zooms?

If you know exactly what you want, then you can work with prime lenses.

Prime lenses are lenses with just one focal length. If you know you like a range, say normal range, then pick a zoom lens in that range. That’s why you see most camera companies have three main zooms – 16-35mm, which is the wide range, 24-70mm, the normal range, and 70-200mm, the telephoto range. See? Other people have already done the thinking for you. The right question to ask about focal lengths is:

How do you see the world? I bet a focal length already exists that will make that come true.

If you’re interested in watching what famous directors prefer as their focal lengths, you’ll love this video:

Exclusive Bonus: Download my free guide (with examples) on how to find the best camera angles for dialogue scenes when your mind goes blank.