How the human eye sees light

[Zhibo Lai]

It has always fascinated me how our human eyes can beat the top cameras in resolution, sensitive, dynamic range, FoV, etc.. Just curious, is there a camera/lens that beats the human eye in every respect?

But on to my real question. Say you are shooting an indoor scene with all indoor 32K lamps and your camera is white balanced for that light. But as soon as someone opens a window, you get blue light from it and blue spill onto your scene. But the same is not true with the human eye, correct? I don't ever recall seeing blue light coming from the window while I'm indoors, or orange light coming from a house while I'm outdoors.

What is it about the human eye that lets it white balance to both multiple light temperatures? Can the same be done with digital cameras?

[Joseph Hutson]

Originally Posted by Realogist

What is it about the human eye that lets it white balance to both multiple light temperatures? Can the same be done with digital cameras?

Maybe if God built a Digital Camera?

[Jason Murphy]

Well, at the end of the day, it's probably a good thing for all of us that God has many more important things to do than design a digital camera. Besides, Jim & Co. seem to be doing a pretty fine job, all things considered.

Seriously, though, there is no camera out there that beats the human eye in every respect. Obviously, some cameras and optics certainly can do many things that the human eye cannot; high speed cameras obviously sample time at rates that allow us to re-view it at a completely different speed than we ordinarily do. There are cameras/films that are sensitive to the infrared spectrum, and large format film cameras can often capture images at significantly higher resolution than we might be able to see normally, etc. So, many cameras/tools we use are superior to the human eye for specific functions.

But nothing made yet has the flexibility and/or adaptability of the human eye. Certainly in terms of quickly adjusting to different levels of light, or rapidly changing focus between two objects, etc.

Much of this is, of course, not the eye: it's the fault of the human brain, which processes what our retinas capture. It's essentially the brain which normalizes the color of light on the fly so that in most mixed-light situations, we don't even notice that the color temperature often radically shifts. (This is one reason that color correction can be tricky as all hell; we adjust to color casts. So, for example, a grey square on a green background will look different to us than the same grey square on a red background. It's all context, and our brain is pretty ruthlessly efficient at doing these adjustments.)

Another good example which you can try at home:

http://www.colorcube.com/illusions/chrmadpt.htm

Another way of thinking about it that might work better for this board would be to say that our eyes capture the image in RAW (upside down, as well) and our brain is the computer that does all the post-processing and color correction in real time. Assuming everything's working properly.

All that said, you can train yourself to notice relative color differences to an extent. When looking at a scene with mixed light sources, you can train yourself to recognize that one source has a bluer color cast (ie. higher color temp.) than another. It's just that we don't usually do this, and therefore don't notice it. But even with training, your brain will still adjust, and eyeballing is generally not a reliable method of color measurement.

[NoahK]

The eye is just very adapt at adjusting to wide dynamic range and has excellent fast white balancing. Think of it as the ultimate digital camera. in fact it's actually the one thing that makes most movie's lighting suck because it's very easy to fool your eyes into seeing light that looks good when in fact it has too much contrast or mixed color temperatures that will look bad on film or video.

Noah

[Dances With Cameras]

The eyes and our brain could be called "analog" "devices".

When we dig deep into the question how our "machinery" works and why, we might reach philosophical questions.

Personally, I think that we humans still know very little about ourselves.

Our know-how is increasing fast, but our know-why is falling behind.

Sooner or later, a camera will be developed that beats the human eye.

But the comes the question: "So what?"

I mean, life and art aren`t just about the perfect device.

What is life? What drives this bio-machine? Why? etc...

I recently re-watched Contact several times.

A VERY smart movie, highly recommended. It treats these problems in a unique way.

Makes you wonder, does science make life actually better?

Or, does my film become better now that I have a better camera?

Complicated stuff.

I think the path of reason and logic is certainly helpful, but it doesn`t solve everything...

Anyway, I think the sensor of digital cameras is supposed to be analog, if I'm not mistaken.

But then it feeds the signal to the analog-to-digital converter, which (somehow) transforms it into 001001100.

[Tim Hole]

Don't forget humans also see through association and imagination. Switch between creative and logic. Our brain conjurs up possiblilities and we chose one!

In some respects though the human colour correction function doesn't work at all because there is no standard just a variable.

[Dances With Cameras]

Yeah, it's true.

Actually I'd say that most of what we think we see is actually produced by our brain.

The Matrix has us.

[Jason Murphy]

Originally Posted by IndiEvolution

Don't forget humans also see through association and imagination. Switch between creative and logic. Our brain conjurs up possiblilities and we chose one!

In some respects though the human colour correction function doesn't work at all because there is no standard just a variable.

True enough. Though I think it's more true to say that our brain conjures up possibilities and then picks the most likely without our conscious input.

Perhaps "color correct" isn't the best term to use for what our brain does. "Constant chromatic adjustment" might be a bit better.

Originally Posted by Dances With Cameras

I mean, life and art aren't just about the perfect device.

...

does my film become better now that I have a better camera?

Of course not. I think (or at least sincerely hope) that most people will recognize this. Each device, be it camera, eye, brain, computer, whatever, comes with its own limitations; an important part of life and art is about figuring out how to work around those limitations.

That said, one thing that can be said definitively is that photography changes the way we see things. Some of the best photographs and films actually have the ability to show us things that we have not seen before (and no, I'm not talking about massive CGI-filled battles or anything here), or show us ways of seeing that we could never have come up with by ourselves. And in so doing, they can actually alter the way our brains perceive what we see.

[Bryan Arnold]

I think the eye is more like a lens with autofocus, auto-iris plus a sensor. The information from the sensor is processed and stored by the brains. So the actual capturing is done by the brains.

I read in "What the bleep do we know", I believe, that we're processing Terabytes/sec but are only aware of Gigabytes/sec or something like that. That's kinda like the background processes on my computer. Maybe human vision works in a similar way. We're seeing more than we're aware of and can therefore not copy this exactly with current technology. The answer may not lie in the resolution or sensitivity but in 3d vision or stuff that has yet to be discovered.

[MattN]

Originally Posted by Jason Murphy

Well, at the end of the day, it's probably a good thing for all of us that God has many more important things to do than design a digital camera.

I think you mean "evolve a digital camera"

We are definitely going to have screens with resolution higher than a human can perceive in our lifetime, we're already pretty close as it is. The thing to remember is that we don't really process much out of our central focus region. Unlike a camera which captures the entire image in uniform detail.