Photography is a subject where you can easily get lost in jargon and technicalities. But some of the concepts are fundamental to understanding how a camera works. One such concept is Field Of View or FOV for short.
In this guide, I will demystify the concept of Field Of View and how it differs for various lenses, cameras, formats, and distances. All this will be illustrated using video tutorials throughout.
The first question you might ask is why Field Of View is important. Well, in terms of photography it describes the amount of scene captured by the camera.
This is important because to some extent it determines what we can see in a photo. A camera with a very small FOV will only capture a small part of the total scene, so we won’t get to see much.
On the other hand, a camera with a very large FOV can capture almost everything, so we’ll be able to see a lot more details and relationships within that scene.
What Is field of view
What Is field of view (FOV)?
Field of view is a measurement of the area that a camera lens or eyepiece takes in at one time and is expressed in degrees. This may be known as angle of view or panoramic viewing angle.
Taken from the context of telescopes, it refers to the size of the image captured by an instrument’s optics.
The field of view is also dependent on the magnification power of the instrument since this has a direct effect on the angle at which an object appears to be viewed.
What’s Field Of View (FOV)?
Field of view is the area that a lens can see through at once. You can see it if you hold an object close to your eye, then move it around and note the angle at which you lose sight of it. That’s your angle of view.
The term field of view is usually associated with cameras but can also relate to telescopes, microscopes and other optical instruments.
The human eye has a field of 170 degrees horizontal, 180 degrees vertical, and a diagonal field of 220 degrees.
For this reason, one degree is taken as the basic unit for all fields of view. *(see note below for more information)
To give you an idea, let’s look at some common fields of view:
If you’ve ever used a camera with an optical viewfinder then you will be familiar with this concept. If the angle was slightly wider, then the image would be slightly distorted. There would appear to be more space between the top and bottom lines.
This would make reading text very difficult as there would be less space between each line than there actually was in real life.
The field of view can be measured by dividing a circle with a diameter equal to the distance between the observer’s eye and the optical center into sections that are each equal to 1 degree.
With this method, the total field of view will vary according to the distance between observer and lens.
In photography, field of view is used to describe how much of a scene can be seen in a single image.
It’s important for photographers to know what their equipment can capture so they can decide how much area they want in their shot.
The wider the field, the more area will be captured and potentially more can be included in one picture.
Lens Focal Length Examples
Let’s take a look at how far away the camera is from the subject when using different focal lengths. This will give you a better idea of which focal length you need to achieve the shots you’re going for.
There are two ways to get a sense of what any given focal length will do — use your own body to help demonstrate what each lens does, or use something else that has roughly the same dimensions as your body and move it further away from the camera for each focal length. Let’s start with this first method.
The first thing we need to do is establish what the various focal lengths actually are. The table below shows common short (wide angle), standard and long (telephoto) camera lenses and their equivalent focal lengths on a 35mm camera:
We’ll be using common, consumer-grade lenses here, but high-end Canon and Nikon lenses have their own names for their equivalents in the table above.
In particular, Canon refers to its wide angle lens as “ultra-wide angle” (16 – 24mm), while it calls it’s 35 – 70mm lens a “normal” lens.
Similarly, Nikon calls its ultrawide angle lens “very wide angle” (10 – 24mm) and its 35 – 70mm lens a “normal.”
What Is Focal Length And Field Of View?
The focal length of a lens is the distance from its optical center, where light rays converge, to the film or sensor.
The shorter the focal length, the wider the angle of view and vice versa. For example, a 40mm focal length has a narrower angle of view than an 80mm one.
Determining the right focal length for a lens is the key to making panoramas work. Most photographers use overlapping images taken at different focal lengths to make panoramas.
Photographers can also change their point of view by moving forward or backward from their shooting position.
In either case, keeping the camera level means you can stitch your images together seamlessly with no distortions or parallax errors.
A good rule of thumb for creating immersive panoramas is to take photos at least 10 degrees apart in terms of viewing angle.
For example, if you’re taking photos around a 90-degree arc, you’ll need to move your camera 10 degrees in order to shoot all the images necessary for stitching into a panorama.
The only exception to this rule is when you’re shooting architecture: You can use shorter intervals between shots because buildings are typically symmetrical, so small errors won’t matter as much as they would with other subjects.
How Is Field Of View (Fov) Calculated In Photography?
The field of view depends on several factors, including the focal length of the lens and the distance from the camera to the subject.
All lenses have a specific angle of view, which is generally expressed as an angle. A lens with an angle of view of 45 degrees will capture a scene very similar to what you see when you look at an object with your eyes.
When this angle decreases, less is visible to the camera. If you use a wide-angle lens with an angle of view of 15 degrees, more than three times as much can be photographed than if you use a normal lens with an angle of view of 45 degrees.
FOV also depends on the distance between the camera and its subject. The closer objects are to the camera, the wider your FOV becomes.
This is because shorter focal lengths require shorter distances between the camera and its subject for proper focusing.
The Importance of Field Of View In Filmmaking
It is important to understand the basics of film field of view. Field of view is the amount of your shot that is visible to the camera.
It’s also referred to as angle of view or coverage. It’s important to know that different lenses have different fields of view. You could have a wide angle lens or a telephoto lens for example. Each one will show a different field of view.
This can be very useful in filmmaking, as you may want to use a wide angle lens when filming something close up and then switch to a telephoto lens when filming something further away.
Field of view also depends on what format you are filming in, whether it is 35mm, 16mm or Super 8 mm for example.
This can be confusing for many people trying to work out what format they should use when making their films.
Generally speaking, if you want your film to look like it was shot on a larger format, such as 35mm, then you should use 16mm or Super 8 mm and vice versa.
The amount of information you can capture within the frame will depend on your field of view. A wider angle lens will capture more information.
Lens Field Of View Comparison
Aperture is the opening in a lens that controls the amount of light entering the camera. The size of the aperture is measured using an f-number (or f-stop), which is the ratio between the focal length and the diameter of the aperture.
In other words, it’s a mathematical way to express how much light enters your lens when you take a picture.
The lower this number, the more light enters your camera. The higher the number, the less light.
An f-stop of 1.4 means that one unit on your lens (which could be 1 mm or 1 cm) lets in as much light as an aperture of 1.4 meters in diameter, while an f-stop of 22 means that one unit on your lens lets in as much light as an aperture 22 meters (72 feet) in diameter.
It’s not uncommon for photographers to refer to f-numbers by their actual diameters: “f/1”, “f/2” and so on refer to an aperture 1 unit wide, 2 units wide and so on. Since these numbers can get pretty big, it’s common to use “f/” instead of spelling out “focal length”.
For example, saying “the circle of confusion is 0.03 mm.
Why Is Field Of View Important?
A typical focal length on a standard lens for most DSLRs is roughly 35mm. If you’re not familiar with photography terminology, 35mm is actually just a focal length.
It’s not really telling you anything about the field of view. To figure that out we have to do some math.
The 35mm lens is roughly equivalent to our eye’s vision when we look at something straight ahead, so it makes sense that most people think it’s how we see (and therefore how our cameras see).
This isn’t the case though since there are other factors involved such as crop factor (1.5x for Canon, 1.6x for Nikon, 1.3x for Sony), perspective distortion, and angle of view (which I’ll explain later).
Fixed Focal Length Lenses
Many people are unsure what Fixed Focal Length Lenses are, or if they should be using them. This article will help you decide if Fixed Focal Length Lenses are right for you.
Where Optical Zoom Is Used?
Optical Zoom is used in cameras to allow the photographer to adjust the angle of view without having to move closer or further away from the subject.
This is usually done by moving lenses closer together or further apart and changing the length of the lens through extension tubes or bellows.
These movements change the focal length itself. The difference between optical zoom and digital zooming is that optical zooming is done with moving lenses while digital zooming is accomplished with image manipulation software to make the image bigger, at the expense of detail in an image.
What Is A Fixed Focal Length Lens?
A fixed focal length lens does not have any moving parts within it that allow you to adjust the angle of view. It will remain fixed at one focal length throughout its usage. These lenses produce some of the most beautiful photographs since they do not distort reality like zooms do.
A great example of this can be seen when using a wide-angle lens on a close object as shown below.
Using WD And FOV To Determine Focal Length
I’ve seen a lot of confusion online about what WD and FOV mean in photography, so I figured it was worth posting an article to explain them.
The term Focal Length (often abbreviated FL) is used by photographers to describe the effective focal length of a photographic lens.
It is often useful to distinguish between the optical focal length, which is the physical length of the lens, and the effective focal length, which takes into account the orientation of the sensor or film plane with respect to the optical axis of the lens.
If a camera has a sensor that is rectangular, as opposed to square, then this distinction becomes important because it changes the angle of view, making a 35 mm lens have an effective focal length around 32 mm on a 6 by 4.5 cm sensor and around 28 mm on an APS-C sized sensor.
FL and WD are related in that they both use different units of measurement (meters and degrees on one hand vs inches and degrees on the other). They are also both representing different aspects of how wide your lens can see.
FL tells you how wide your picture will be.
Calculating FOV Using A Lens With A Fixed Magnification
Calculating field of view (FOV) using a lens with a fixed magnification is easy to do. All you need is the angle of view, focal length and camera-to-subject distance.
Trying to work out the FOV for a given camera and lens combination can be tricky, so here’s a simple formula you can use to calculate it:
A = H x Focal Length (L) / D where:
A = Angle of View (in radians).
H = Height of Camera above subject (in meters).
D = Distance from Camera to Subject (in meters).
Focal Length (L) = Fixed focal length of the lens.
You can also use this formula to calculate A if you already have the height of the camera over the subject and the distance from the camera to the subject.
Dividing Height by Distance gives you the height per unit distance, which is important if you want to determine how large an object will appear in your photo.