How a Video Camera Works, a Detailed Breakdown

How a video camera works can be a complicated question to answer. A video camera used to be devices operated only by skilled technicians working at media companies. But today, everyone with a cell phone (and that is just about everyone, everywhere) carries a video camera in their pockets.

Yesteryear, only skilled technicians shot videos; nowadays, no expertise is needed. Despite the differences, the process of opening up the lens and capturing the action remains essentially the same.


Let There Be Light

The first step in recording a video image is to open the lens and focus on whatever you want to shoot. Much of your success or failure depends on the lighting, so you want to move the lens toward the light when it is dark and vice versa when it is bright.

Many cameras nowadays include an autofocus feature. Here, an infrared beam typically bounces off objects in the center of the frame and returns them home to a sensor in the video system.

The device is smart enough to calculate how long it takes the beam to make its trip. It then controls two parts to create the best images possible. The aperture is the size of the opening in the camera. The shutter speed controls the amount of time that light passes through the aperture.

The Record button begins the shooting. Varying degrees of light are sent into the lens and shined onto a small semiconductor image sensor. A sensor measures light in a half-inch (about 1 cm) panel of 300,000 to 500,000 tiny light-sensitive diodes called photosites.

Each photosite measures the number of photons that hit each point and translates it into electrons (electrical charges): A brighter image is represented by a higher electrical charge, and a darker one by a lower electrical charge.

In the past, video was captured by analog devices, but the industry moved to digital technology and storage systems. Key features ultimately define the quality of a video. 

  • A Codec (Compression/Decompression Module) is a program that encodes and decodes video signals. Typically, it stores videos in more than one – but not all – file formats.
  • Resolution is the number of pixels in a single frame of the video. The higher the resolution, the sharper the picture. Common resolutions are 480, 720, 1080, 4K, and 8K. But picture quality also depends on the size of the device. A 720-pixel video may look amazing on a mobile phone but blurry when viewed on a 75 inch TV screen.
  • Aspect Ratio is the ratio of width to the height of the video on a screen.
  • Frame Rate is the number of frames captured per second (fps). Moving to higher frame rates provides richer viewing experiences but also requires more storage space, is more complex, and usually carries a higher price tag. A 24 fps system is typical for commercial items, like movies and TV shows; HD systems operate at about 60 fps.
  • Bitrate is the data transferred per second and is measured in bits per second. This attribute is key when you view streaming video. Higher frame rates require higher-speed connections or else the picture may stop or jump when moving from frame to frame.
  • Digitize Your Video 

Initially, a video camera uses the device’s internal memory to store its images. Video is a complex and hefty media. Through the years, a number of formats emerged to mitigate its potential problems. Here are a few popular ones.

MP4, which has been widely available for more than a decade, is quite common. Apple developed it, and it gained popularity with the iTunes player because it delivers high-quality video and requires relatively little storage space.

Apple also created MOV, which is used in Apple’s Quicktime video player and also runs on Microsoft Windows. This format was designed to deliver high-quality videos but requires high performance and robust storage systems.

Adobe created the Flash Video Format (FLV) that works with the Adobe Flash Player. It can be embedded or added as a plugin tor web browsers.

WMV, short for Windows Media Video, is both a codec format and a video file container.  Developed by Microsoft as part of the Windows Media Framework, this format was initially created for hosting streaming websites and applications. It creates very small files compared to other video formats and is popular with platforms, like email, where file sizes are limited.

Store Your Content 

Digital camcorders record information digitally, as bytes, which means the image can be reproduced without losing any image or audio quality. Digital video can also be downloaded to a computer, where you can edit it or post it to the Web.

Initially, users stored their videos locally, but they often took up too much space. A variety of memory cards emerged, such as memory sticks, SD cards, and flash memory. Increasingly, consumers house their videos in the cloud, with services from vendors, like Apple, Amazon Web Services, and Google.

As network bandwidth and system processing have increased, video has become a popular type of content. Social networking sites, such as Instagram and TikTok, gained popularity because of their rich arrays of video content.

Consequently, new twists will emerge, and current formats, speeds, and capabilities evolve, but essentially the process of shooting and storing video will remain the same as it has been in the past.