Understanding The Difference Between Digital Cameras And The Human Eye

Being able to capture a significant moment in your life and look back on it is one of the best feelings that you can have. Over the years, we’ve attempted to do this with photography, doing the best job that we can to replicate what we see and preserve it. However, our eyes are an incredibly complex piece of natural wonder.

The human eyes really are a masterpiece of nature that we are still a lifetime or two away from being able to understand fully to the point that we can reproduce them. From the iris to the pupil to the retina, they are nothing short of spectacular in the way that they are perfectly designed to perform their function, giving us a near-perfect visual understanding of what we see in front of us.

The closest thing that we have to imitate the human eye is the camera, a piece of technology that has been honed over the years to get the image that is captured as close as possible to what our own eyes perceive. We have pushed closer and closer to that goal with modern digital cameras, but we still have a long way to go.

Much of digital camera design uses the way that our eyes function as a blueprint for how to capture images. The lens of a digital camera and the “lens” in our eyes capture light similarly. In a lot of ways, the digital camera is a pale imitation of our eyes. So, where do the camera and the eye differ in the way that they produce an image?

The difference in the lens

One of the first steps of capturing an image is the way that light is handled. Light will bend through the lens of both our eyes and the digital camera to create a clear vision. The first thing to address is the way that the human eye captures light. An excellent method of explaining the difference in the way the lenses operate is to look at low light scenarios. A camera will have a very static way of handling light and a finite limit on the lower limit of light it can handle. This limit is what will cause a camera to take an incredibly poor picture in a more moderate light scenario, versus what we see.

Our eyes have various muscles in them that make them adept at altering focus and shape to adapt to those situations. Just, generally speaking, this is what makes the lenses in our eyes so unique. They will always be adjusting to the various levels of light, shapes, and colours in real-time, with those muscles constantly tweaking to suit the environment.

Where this can get confusing is when you begin to introduce the concept of ISO, which determines the sensitivity of a sensor to how well a camera will capture light vs. how much noise will be present in the image that is presented. It’s borderline impossible to compare the ISO of a camera to the lens of the human eye. However, it’s fair to say that while the human eye is far more adaptable, there are, in fact, cameras that are capable of incredibly high ISO levels. Such high ISO levels mean that they can capture images more effectively at extreme levels of low light, even beyond what the human eye can see.

Image processing

While a camera will record the light being reflected on the lens and essentially “save” the image as a digital file, our eyes work very differently. It isn’t so much that our eyes produce the pictures that we see, but that our eyes deliver the information to our brain. The retina is where the difference is and is responsible for much of the magic that takes place. The retina will send all of the information from the lens and the eye muscles to the brain in the form of electrical signals. Our mind will then process these signals to provide the image that we see. This process brings us to another interesting area of difference between a digital camera and the human eye.

Both what we see and the images created by high-end digital cameras can appear to be “perfect.” In the case of the digital camera, it works very hard to produce this image accurately without any noise or issues. Interestingly, even though what we see looks perfect, it’s anything but that. One of the jobs that the brain is responsible for is weeding out any “incorrect” information that it receives from the retina. If the lens of our eyes collects any information that is hard to understand or process, our brain will simply fill in the gaps. This difference is one of the biggest differences between our eyes and a digital camera.

A lot of the way the images we see are produced is based on a kind of visual memory, leading to a digital camera often capturing things that we don’t notice or see.

More similar than different

Although there are a fair number of differences in the way our eyes and a digital camera function, there is an incredible amount of similarity in the theory behind the way they operate. One of the most substantial similarities, and perhaps a strange fact about your eyes in general, is that the images we see are initially received upside down. We simply don’t see them upside down because of the way the retina and the brain compensate for this. Strangely, cameras also operate in the same way, which is because camera lenses mimic the same curved shape as our lenses to refract light.

The greatest difference is…

Above and beyond all of this, is the fact that whilst we might see a picture with our eyes, we are seeing it in 3D. We see the differences in the scale of things and our brain and other senses add to the memory we have in our mind. Things like the smell of a place, the feeling of heat or cold and even that sense of trepidation when you stand on a cliff can’t be replicated in an image. That is why to replicate this in a photo you need to work harder. For example to convey a sense of scale you need to place a point of interest in the composition. Or you may need to show a plate of food for the viewer to get a feeling of the smell. But however hard you try, there are some things that simply can’t be replicated.

The human eye is an incredibly complex “camera” that we may never be able to replicate. But high-end DSLR cameras have come a long way since the invention of photography equipment and even from the days of film. The inspiration behind it all was our eyes which is why it’s important to understand the theory behind the differences between them.

Photo credits: Kav Dadfar – All rights reserved. No usage without permission. Dreamstime.