You can make a pinhole camera yourself. It's easy. Just get a box with a tiny hole such that it projects an image on the inside wall of the box. Then you need to make some type of viewing hole so you can peek inside to see the image. You have to be careful with the viewing hole, because if you let in any extra light, it will wash out the dim pinhole image.

The sensor size of the camera also plays a significant role in determining the field of view. A larger sensor size will provide a wider field of view for the same lens, capturing more of the scene.Conversely, a smaller sensor size will result in a narrower field of view. The crop factor, which is the ratio of the sensor size to a standard full-frame sensor, further impacts the FoV. A larger crop factor means a narrower FoV, effectively magnifying the image. Understanding how sensor size and crop factor affect your FoV can help you choose the right camera and lens combination for your camera hardware design project.

Now let’s take it up a notch. What if I have two lights? Suppose I put an orange light above a green light, about 6 inches apart. What will appear on the screen? This isn't too hard to set up. I taped two LEDs to the ends of a pencil and used button cell batteries to light them up:

People have been building image viewers with this trick for hundreds of years; it was originally known as a camera obscura, which means “dark chamber.” The idea was, you get some people in a dark room with only a tiny hole open to the outside. It seems magical, but the light from that hole would project an image of the outside world onto a wall in the room.

Angle of view calculator

This calculator provides the camera's field of view based on an image sensor and a lens. The field of view of a camera is dependent upon the focal length of the lens, the image sensor size, the lens distortion, and the lens image circle. We also have a wide angle lens FoV calculator which provides the field of view for our lenses on your camera's sensor.

Now, a question: What's the difference between a pinhole and the lens in a modern camera? If you want to know how a lens or a mirror makes a "real image" that can be recorded on film or a sensor, check out this older post. But basically, the lens bends light from a source so that the rays converge at a particular spot, forming a coherent image at that spot.

Fov calculationcalculator

No, the image quality isn’t great. And yes, I realize I could have just used my phone to take the video without putting it in a box. But where's the fun in that? Honestly, this is a great project for you while you’re stuck at home. In this video, I show you how to build one of your own—it only takes like five minutes—and for a bonus you get a pinhole tour of my backyard.

© 2024 Condé Nast. All rights reserved. WIRED may earn a portion of sales from products that are purchased through our site as part of our Affiliate Partnerships with retailers. The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of Condé Nast. Ad Choices

Those crescents of light are essentially pinhole projections of the sun during the 2017 solar eclipse, at a moment when the sun was mostly obscured by the moon. The holes are formed by tiny gaps in the leaves of an overhead tree. Although the sun looks very small from Earth, with an angular size of about half a degree (note: never look at the sun, you fool), the images are quite large due to the distance from the "pinholes" to the ground. It's pretty cool.

1.) The effective focal length of the lens (EFL)The EFL of a lens is a first order optical parameter. It should not be confused with the Back Focal Length (BFL) or the Flange Focal Distance (FFD) which are mechanical parameters. 2.) The image sensor active area The image sensor active area is calculated by using the pixel size and the total number pixels in the resulting image/video. If the output image or video is cropped, the field of view will change. 3.) The relative illumination of a lens The relative illumination is the reduction of light transmitted through a lens, as a function of position in image space. The camera industry loosely uses the term “Image Circle” as the position in image space where relative illumination is ~50%. 4.) The distortion of a lens Lens distortion is an aberration that occurs in optical design. Distortion is common in wide angle and fisheye lenses, but can occur in normal field of view lenses. Distortion increases the Field of View of a lens by compressing the angular resolution.

I used a piece of aluminum foil mounted to some cardboard. The foil is nice because it's easy to make holes in it, and the holes have nice clean edges. So let's see it then. Here is what I get on the screen:

Fov calculationcamera

Oh, but the big spot is on the right, just like the big hole is on the right. Why aren’t they reversed like the colors? This next diagram should make it clear. It’s a view from above showing just the green light and the green spots on the screen:

How to calculateFOVmicroscope

Of course, later on, if you didn’t want to get in a dark room, you could replace the people with chemical film, and boom: You had a pinhole camera. I’m going to go one further today and build a pinhole video camera. You can do it too! I have a video at the end of this article that will show you how, using basic materials you have at home.

But wait! There's a better way to do it. Instead of cutting a second hole, you can just put your phone inside the box, positioned so it's pointing at the screen. In fact, why stop with still images? You can use this setup to make a pinhole video camera. Here’s what the footage looks like—that’s me (upside down) waving:

I'm honestly surprised this picture turned out so well. I give credit to the iPhone camera's performance in low light. But why are the colors now reversed, with the green spot above the orange spot on the screen? It's easy to see with a simple light-ray diagram:

What does all that have to do with a pinhole camera? Instead of two LEDs, imagine you have a person standing in bright sunlight. The light hits them and reflects in all different directions. But some of it will go through the hole. Light from their head will pass through and make a spot on the bottom of the screen. Light from their feet will make a spot on the top. And so on for all the rest of their body. Put it all together and you have an upside-down image of the person.

Fov calculationonline

The camera field of view (FoV) is a crucial concept in photography that determines the area visible to the camera lens. Measured in degrees, the FoV is influenced by both the lens focal length and the sensor size.

So, there are two big differences with an image formed from a lens. First, the hole (or aperture) can be much bigger than a pinhole. Really, you could make it as big or small as you like. This bigger size means that a lens can collect more light and form a much brighter image. You don't even need to be in a dark room to see it.

Second, the lens forms an image only at a specific location. The location of the image depends on the properties of the lens (the focal length) and the distance from the object to the lens. That means your screen has to be at the location of the image in order to see anything. With the pinhole, the screen can be anywhere. If you move the screen farther from the hole, you get a bigger (and dimmer) image.

CalculateFOVfrom focal length

Surprise! I didn't draw light rays. Instead, I made some light cones. Since the holes aren’t infinitely tiny, there are many light rays that can pass through. The light cone represents all of these rays.

FOVto focal length calculator

The lens focal length is a critical factor in determining the camera’s field of view. A shorter focal length, such as 2mm, provides a wider field of view, allowing you to capture expansive scenes. On the other hand, a longer focal length, like 50mm, offers a narrower field of view, which is perfect for zooming in on distant subjects. It’s important to note that the focal length of the lens is used to calculate the FoV. Changing the focal length of the lens will directly alter the FoV, even if the sensor size remains the same.

CalculateFoVfrom image

OK, how about this: What if there’s a second, bigger hole next to the first hole—side by side. What pattern would you see on the screen with the orange and green lights? Go ahead and draw your answer somewhere, I'll wait. Meanwhile, here’s a picture of the setup:

Most of the light rays go off in different directions and have their own story in some other blog post. Some of them hit the barrier and bounce off or get absorbed. But a few, at just the right angle, get through the hole to the viewing screen. These rays then reflect off the screen and give the appearance of a bright spot.

The simplest way to project an image onto a screen is with a pinhole. What the heck is a pinhole? It's a hole so tiny it has to be made with a pin. See, science isn’t that hard.

Couldn't you just use a bigger hole? Yes, but the image would be blurry. To see why, look back at the diagram with the LEDs shining through the two holes: The bigger hole made a bigger spot. If you had a human who was made of 100 colored LEDs (which would be both weird and cool) going through one big hole, there would be 100 big spots on the screen, all overlapping with one another. The tiny pinhole projects tiny spots, so we get a higher-resolution image.

In fact, let’s go back to the simplest possible case. What happens if I have a point light source in front of a barrier with a pinhole in it. Here is a diagram:

Admittedly, it’s a very dim image. If there’s any other light leaking into your device, you won't even be able to see the image. Why is it so dim? Because the hole is so tiny—only a little bit of light from the person makes it to the screen.

Since the orange light on top can only go through the hole one way, the only option is for its spot to be on the bottom. And vice versa for the green light. All clear now?