Vision – Eye vs Camera

Here one recent high dynamic range photograph:

And here the underlying individual images:

I think it’s time to clarify another myth about photography.

As a continuation of my last article, I thought I’ll explain a bit more about the differences between eye-vision and camera vision, and a bit about <reality> (=perception) itself.

At first glimpse, the human eye and a camera seem to have a lot in common. Both have a lens, an aperture (iris) and a sensor (retina).
But that’s where similarities end.

A camera <sees>, or records, an instant. A status quo of its environment. This instant is a certain amount of time, longer or shorter doesn’t matter, when the sensor is exposed to light. All the information is <written> onto the sensor.

The human eye, though, sees a continuous video. It doesn’t record anything, so everything we see is real-time.

This gives the camera the ability to show things you can’t see without a camera. Here some examples:

Water droplets in mid-air, very short exposure, 1/1000 second or so.

<Milky> water (or waterfalls), longer exposure, 1 or more seconds.

Stars, Milkyway, star-trails, very long exposure, some 15-30 seconds or longer.

Thing is, the human brain can’t really distinguish individual images within very fast image flows. So you see splashing water, but not really individual droplets. The brain also isn’t designed to <collect> image information over a longer period of time, so in a waterfall you see also just splashing water, not the trails of droplets.
Stars in the night sky aren’t very bright. Not for human eyes anyway, because they are not designed very light-sensitive (we aren’t nocturnal creatures). Collecting the light on an electronic sensor enables you to see the light accumulating over several seconds, which makes the whole sky brighter.

Camera and eye focus different.
The human eye has a focus range of roughly 1-2 degrees. If you hold out your thumb, and look at your thumbnail, concentrating on it, you will notice that everything around it is actually blurry. The sharp part is your actual focus window. The rest of the environment is filled in by the brains' memory of the environment.

A camera, on the other hand, can show the whole range of its vision in perfect focus, unless you flatten the depth of field to mimic human eye sight. I have a fish-eye lens covering 180 degrees diagonal in one image.

Another big difference is dynamic range.
The human eye has a high dynamic range (=HDR) compared to a camera. Dynamic range is the capability to see details in shadows as well as in bright parts of a setting.
A good example is a sunset with a person in the foreground. In such a setting, you will see the sunset in all its beautiful colors, and are still able to recognize the person in the foreground. This happens due to the slim focus range I mentioned above. You look at the person directly and the brain adjusts the background lighting, so you see both – person and the light show in the background.

A camera, however, would either adjust to the person or the sky. You might have noticed if you ever tried to take a photo in such a setting. Either the sky looks awesome but the person is just a silhouette, or the person looks good but the sky is blown out (means far too bright, even just white). It depends where you point the focus point, either to the person or the background.

To overcome this issue, one can take multiple images with different exposure times, usually 3. One under exposed, one normal, one over exposed. Then those three images can be combined to one single image. The result will show the foreground as detailed as the background. The image above shows such a final image, and the three individual images.

Things like that aren’t <tricks>. What I said about HDR is done by your brain as well, hence you are able to see as you do. It also does not mean these other techniques I mentioned above are <tricks> or they weren’t <real>. It only means you use a different type of vision, one your eye can’t reproduce by itself.

Both, camera and human eye see <reality>, but they have different ways of seeing it.
Both, camera and human (or any other known) eye produce not an image, but electric signals. In both cases those signals are interpreted (actually edited), to make sense and create a visual image. In a camera the first part of this process happens within the camera, in its operating system, the second part, if needed, on a computer. In a human these things happen within the brain, which technically is pretty much a computer as well.

There are a lot more different ways of seeing in nature, like cats seeing much better in darkness. Insects see a compound image delivered by some hundreds of individual eyes. Most insects can’t see infra-red light, but they see ultra violet light, so colors look entirely different for them. Most bats <see> via ultrasound, snails see only bright and dark.
Even for some humans <reality> looks different, a colorblind person still sees <reality>, only in different colors, but nonetheless real.

You see, reality is a pretty subjective thing. It’s also a purely human concept, not a natural one. It becomes only important due to a form of language. Without communication reality, as we define it, has no meaning whatsoever. It’s utterly nonrelevant for a fly to know how a cat sees or the other way around.

Humans, on the other hand, have the ability to talk and to share their individual perceptions of their environment. One way of doing this is via art, visual, musical, verbal etc. Because every individual experiences their environment different, there are always some who like some piece of art and some who don’t.

However, this has no effect, whatsoever, on the way the actual creator experienced the reality they <reproduced> or that inspired them to create a certain piece of art. That makes the job of an art critic pretty redundant.
It also has no effect on the underlying reality itself.
So saying something were not <real> is a pretty bold statement, based on one single opinion of one single individual, who wasn't even present, nothing more and nothing less.

The same is true for any piece of art. You can say you like or dislike it, but stating something is art or not, is just an individual opinion. A single opinion, however, can’t be a universal fact.