Why the tiny iii, you ask? This formula holds for all the three possible directions on the sensor: horizontal, vertical, and diagonal.

Using angles, it is 26.5° × 17.7°, vertical and horizontal angle of view, respectively. To calculate these values, input them in the angle of view formula:

The Canon EOS 550D has a sensor size 22.3×14.9 mm22.3\times14.9\ \text{mm}22.3×14.9 mm, which allows us to calculate both the horizontal and the vertical angle of view. Let's not be extreme and use the 24 mm24\ \text{mm}24 mm focal length.

The field number of typical eyepieces varies between 6 and 28 millimeters and (in general) decreases with the magnification of the eyepiece. For example, an eyepiece having a magnification of 10x typically has a field number ranging between 16 and 18 millimeters, while a lower magnification eyepiece (5x) has a field number of about 20 millimeters. Presented in Figure 2 is a comparison between the view fields available with similar eyepieces, one having a field number of 20 and the other a field number of 26. Note the greater range of specimen features visible through the eyepiece having the larger field number.

Field of viewformula

That is an extremely wide angle of view: it covers 170017001700 square degrees! However, you need almost 20 of these fields to capture a true 260°260\degree260° picture.

The diameter of the field in an optical microscope is expressed by the field-of-view number, or simply the field number, which is the diameter of the view field in millimeters measured at the intermediate image plane.

In most cases, the eyepiece field diaphragm opening diameter determines the view field size. The field size in the specimen plane is then defined as the field number divided by the magnification of the objective:

Field of viewmicroscope

Take the diverging lines from the sphere's center to the corner of the scene, and stop them at a certain distance ddd. Now, draw the corresponding rectangle: you will obtain a set of measurements we call the field of view at a distance ddd.

Michael W. Davidson - National High Magnetic Field Laboratory, 1800 East Paul Dirac Dr., The Florida State University, Tallahassee, Florida, 32310.

Field of viewin games

It's impossible to define a typical field of view of a camera: it depends on the lens you are mounting at the moment. However, we can give you some practical examples.

The angle of view of a camera is an absolute measure of the horizontal and vertical angles captured by a combination of camera and lens. The field of view measures the same concept but uses lengths. Since the angles don't change, the field of view depends on the distance: specifically, it increases alongside it.

📷 Cameras are our way to create memories — instants preserved forever — from what we can see. However, their electronic eyes have some limitations when it comes to how much of those memories they record. We may need to think beforehand about what we want to include in our pictures, and many photographers find it helpful to know their cameras' field of view.

If an auxiliary lens is inserted between the objective and eyepiece, the magnification factor of this lens should also be employed in the equation by multiplication with the objective magnification (prior to the division operation). Although the field number is usually limited by the magnification and field diaphragm (stop) size of the eyepiece, there is clearly a limit that is also imposed by the design of the objective lens system. In early microscope objectives, the maximum usable field diameter tended to be about 18 millimeters or considerably less, but with modern plan apochromats and other specialized flat-field objectives, the maximum usable field can sometimes exceed 28 millimeters.

Field of viewcalculator

In all modern eyepiece designs, the field lens is placed a sufficient distance away from the intermediate image plane to ensure that dust or other surface debris and defects on the lens surface are not visualized along with the specimen. The top lens in both eyepiece designs is referred to as the eye lens because it is closest to the eye of the observer.

Field of viewexample

When we use angles to define the dimensions of a picture, we talk of the angle of view. The angle of view is pretty easy to visualize: your camera lies at the center of a sphere, and connecting the angles of the scene you are capturing to its center gives you a set of three angles:

Nikon offers a range of eyepiece options featuring magnification and field of view combinations tailored towards a variety of applications.

Here is the lack of absoluteness of the field of view: its value varies with the distance between the camera and the subject. That's why in the same angle of view, you can fit both the Moon and a passenger airplane.

Humanfield of viewSketchUp

Refine your photographic knowledge with our dedicated tools like the depth of field calculator and our magnification of a lens calculator. Cheese! 📸

A camera captures a rectangular portion of the real world, projecting it onto its sensor. We identified two possible ways to measure the size of that portion:

The Huygens eyepiece, illustrated on the left in Figure 1, is designed with the field lens positioned before the intermediate image plane, which coincides with the field diaphragm. Unlike the Ramsden eyepiece, the Huygens design has a focal point (at the intermediate image plane) residing between the eye and field lenses. In this case, the eye lens acts as a loupe to magnify the intermediate image.

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On the other hand, let's calculate the camera field of view for a typical telephoto lens set-up. We keep the same camera but mount a 200 mm200\ \text{mm}200 mm lens. Insert the values in the appropriate fields of our camera field of view calculator and calculate the angles of view in this case:

Do you want to learn more about the fundamental of photography with a slight technical twist? We made the right calculators for you: the aspect ratio calculator and the crop factor calculator!

The concept of field of view is not unique to photography: check how it differs for astronomers at our telescope field of view calculator. 🔭

🙋 You can use our camera field of view calculator to find the values of the angles and fields of view and to calculate the needed focal length of the lens you need to mount to obtain a particular field of view. We locked the variables associated with the sensor's size: it's unlikely you will change it instead of the lens!

The basic concept underlying the entire matter is that cameras can capture a single, defined portion of the real-world at once. How significant this portion depends on the camera set-up, particularly on the type of lens and camera body used by the photographer.

As a rule of thumb, the higher the magnification of the lens is, the smaller the angle of view. If you manage to fit the Moon in your picture, the vertical angle of view would be around half a degree, but this feat requires a pretty high magnification. On the other hand, a 55 mm55\ \text{mm}55 mm lens on an SLR (single-lens reflex) camera will give you a horizontal angle of view of about 20°20\degree20°.

The size of the eyepiece field diaphragm opening is also dependent upon the correction for off-axial aberrations (coma, astigmatism, and lateral chromatic) of the objective. Recent eyepieces feature highly corrected glass that enables wide-field designs having field numbers of 26 millimeters and greater.

The sensor size of your camera significantly affects the quality of your pictures. A camera with a larger sensor will give you a wider field of view for the same lens, maintaining the same magnification: your subject will be surrounded by more background. The advantages are relative, though: when printing the photograph in the same format, a larger field of view will necessarily translate to a lower magnification.

Even if angles are easy to visualize, they can be hard to estimate (how wide is 5°5\degree5°?). The field of view comes in handy to complement the idea of the angle of view.

What can you capture with this lens? For a distance d=200 md=200\ \text{m}d=200 m, the angle of view converts into the respective linear field of views:

Field of viewcamera

Whether you are planning a photoshoot or just a photography enthusiast, our camera field of view calculator will help you learn the whole picture.

A rectilinear lens is a lens that preserves orthogonality: two straight, perpendicular lines in the real world are depicted as straight, perpendicular eyes by a rectilinear lens. A fisheye lens, on the other hand, distorts them — a small price to pay for an extremely wide field of view!

With our tool, you will be able to calculate the camera's field of view (any camera!), and not only that, there is more to it. Keep reading to discover:

The two first ones define the width and height of the rectangle corresponding to our sensor. Notice that these quantities are absolute: you can place the "sphere" as far as you like (even at an infinite distance), and the angle of view will still be the same.

We define both quantities for three spatial directions, which allows us to calculate a vertical, diagonal, and horizontal field of view for a camera set-up, alongside the respective angles of view.

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Canon produces a rectilinear 11-24 mm\text{11-24 mm}11-24 mm lens — which is insane — that allows capturing sharp wide-angle images. How wide? Let's mount the lens on a Canon EOS 550D and calculate this camera field of view!

⚠️ There is quite a bit of confusion online (and not only) on the matter, with various definitions and interpretations. Here we gave the one that makes the most sense for us, but feel free to disagree and let us know!

Field of viewhuman eye

That is more than enough to fit the whole Colosseum in Rome in a single picture. And all of this standing barely more than the diameter of the arena itself away!

The concepts are used almost interchangeably, as they define the same concept. However, their definitions are different. Let's discover them in detail.

🙋 To find the size of your sensor, search on Google "[your camera model] sensor size": you will easily find the correct values!

The solid angle covered by this set-up is about 272727 square degrees for the vertical one! If you want to take a 360°360\degree360° picture, you'll need more than 150015001500 shots! But at a distance of 200 m200\ \text{m}200 m you would be able to picture an area of 45 m×30 m45\ \text{m}\times 30\ \text{m}45 m×30 m: good enough to take some exciting wildlife pictures without disturbing anyone!

In modern microscope eyepieces, the field diaphragm either precedes the optical system or is located between the lens element groups, as illustrated in Figure 1. This figure presents cutaway diagrams of a Ramsden and Huygens eyepiece showing ray traces through the field lens, eye lens, and field diaphragm. The Ramsden eyepiece (illustrated on the right in Figure 1) has an optical system consisting of two plano-convex lenses having a fixed separation distance according to their focal lengths. The first lens is termed the field lens because it is closer to the plane where the intermediate image is formed in the microscope. The field diaphragm is located between the tube opening and the field lens in the Ramsden eyepiece design.

As for the angle of view, you can identify three quantities associated with the field of view: a horizontal length, a vertical length, and a diagonal length. To calculate the field of view fovi\text{fov}_ifovi​ of a camera in each of the three possible directions, use the following formula:

You already know what the iii means and ddd is the distance at which the field of view is measured. Remember to use the correct dimension of your sensor: you want to use its length to calculate the horizontal field of view of your camera, not the vertical one... unless you are taking a portrait picture.

Think about the Moon for a second more. You managed to fit it into your picture — your sensor! We are talking of a 3,500 km3,500\ \text{km}3,500 km body. You can take a picture of a plane passing between you and our satellite with some luck and good timing. A B747 flying at 6.5 km6.5\ \text{km}6.5 km would almost eclipse the Moon, fitting perfectly in the picture together. Does it mean the jumbo jet is really that jumbo, or that the field of view can be a relative concept, too?