The Camera's Eye: What Does It Truly See?

The human eye and the camera lens see the world differently. While the eye sees the world in video format, cameras capture still images, freezing motion in a way that the human eye cannot. Cameras can also see very faint light, use a very narrow or wide field of view, and view the world from cramped or dangerous places. Understanding how a camera works and how it differs from the human eye can help photographers take better pictures.

Cameras can freeze motion

To achieve this, it is recommended to select a shutter priority mode, which allows the photographer to set a minimum shutter speed, leaving the camera to select the aperture and ISO accordingly. This is a semi-automatic mode, which is useful when photographing moving subjects, as it saves time making manual adjustments.

In addition to shutter speed, other settings can also impact the ability to freeze motion. For instance, a higher ISO can enable a faster shutter speed, although this may negatively impact the sharpness of the image. A smaller aperture can also help to capture the whole subject in focus during movement, but this will also result in a slower shutter speed.

By mastering these techniques and making adjustments according to the specific scenario, photographers can effectively freeze motion and capture sharp images of moving subjects.

Cameras can see a wider field of view

The human eye cannot achieve a very wide field of view. A fisheye lens gives you an extremely wide field of view. Some even offer over 180 degrees of vision, meaning they can see behind themselves! The view is also distorted, so items in the centre of the frame appear larger than those near the edge.

With our eyes, we have neither such a large field of view nor such strong distortion. Fisheye lenses are very good for giving a view of the world quite different from what we see. Note that because of the wide field of view, you need to get quite close to your subject for maximum effect.

Wide-angle lenses can capture a broad landscape, but they can also be helpful in showing your subject (flower, animal, etc.) embedded within its surroundings.

Cameras can see very faint light

The human eye and a camera are very similar in their design and functioning, but the camera beats the eye when it comes to seeing the unseen. There are faint stars in the night sky that are invisible to the naked eye, but when you point a camera towards the same area and take a long exposure shot, you will see many more stars.

The main reason for this is exposure time. It is a measure of how long the shutter of the camera is exposed to light. In the case of our eyes, the exposure time is the time for which our retina is exposed to light without being 'refreshed'. Cameras have the feature of increasing the exposure time to hours, thus making them better at capturing faint stars and objects.

CCDs (charge-coupled devices) in cameras are highly sensitive to light, capturing 60-70% of photons, and the best ones exceed 90% sensitivity. This enables the detection of objects much fainter than what the human eye can perceive. CCDs can efficiently count photons in millions of pixels (megapixels), providing more accurate measurements and digital output that can be immediately analysed by computers.

Additionally, cameras have larger detectors, more pixels, and larger lenses than the human eye.

Cameras can see in black and white

In such situations, the camera's infrared lights and sensors are activated. The camera uses infrared light to illuminate its field of view, and this light falls outside the visible spectrum, beyond what we perceive as red. As a result, the camera sensor can only measure the brightness of the infrared light reflecting off objects, with brighter lights appearing white and dimmer lights appearing as shades of grey.

Additionally, some cameras, such as security cameras, are equipped with infrared sensors and lights that specifically enable them to capture black-and-white footage in low-light scenarios, such as at night or in a dark room. This feature can be toggled on and off, and when turned on, the camera will display a series of infrared LEDs glowing red to indicate that it is in infrared mode.

It is worth noting that even humans see mostly in black and white in very dark conditions. This is because our eyes have separate black-and-white-sensitive cells (rods) that function in low-light environments.

Another reason for a camera displaying in black and white could be a technical glitch. For instance, if the camera's infrared sensor gets stuck in the "on" position due to a glitch, it may continue to capture black-and-white images even when there is ample light. Performing a power cycle or checking the camera lens, sensor, cable, and power source for any issues can help resolve this problem.

Cameras can see small details

Even everyday objects can look very different when captured at the macro level, opening up image opportunities you may not have considered before. For example, you can count the hairs on a spider's leg or the scales on a butterfly's wing.

The focal length is the most important factor in determining how far your security camera can see. The larger the focal length, the narrower the field of view and the larger the objects seem.

The field of view is very important for surveillance camera projects as it describes which part of the scene you can see. The wider the field of view, the more you can see of your scene, but fewer details are available as objects appear smaller and farther away from the camera.

High-resolution security cameras can increase their ability to deliver usable images and videos from a distance. For instance, 4MP or 5MP cameras can provide surveillance videos with clear and vivid details, which is what you want in a security camera.

The quality of your security camera also matters when determining the range of outdoor security cameras. Top security camera brands are more dependable when it comes to reliability, durability, and quality.

Frequently asked questions