What the Camera Sees

lighting, DOF, shutter speed considerations

One of the important things every photographer has to learn is to see what the camera sees. It is a different process from painting or other visual art. It is a technical process, not only of how the sensor works but the transform of a 3 dimensional world to a 2 dimensional representation. This is part of our art. We have to understand it and be able to predict the results.

Static image

Unless you are shooting video, the end result of the camera’s capture is a static image. That seems like a “duh” to most of us, but it is significant. The entire image is recorded “in one instant”. Yes, I’m ignoring moving shutter slit, HDR, panoramas, time exposures, and other exceptions that can bend the rules.

This “in one instant” is significant because our eyes work in a totally different way. We can only see a small spot at a time. We continually “scan” around a scene to “see” it all. Our brain stitches all these scans together marvelously to give us the impression of a complete scene. We are not aware of it happening.

What difference does it make? Well, there are subtleties. If something moves in real life, our eyes jump to the movement and study it. Movement has a higher priority in our brains than static things.

Our photograph no longer has that movement or flashing lights. It is a flat and static collection of pixels. We have to learn techniques to stimulate the viewer’s eye in other ways. We learn that the eye is drawn to the brightest or highest contrast areas. That informs how to capture the scene and process it to end up with results that help direct our viewer to the parts of the image we want to emphasize. It helps a lot to anticipate what we are going to want to do. This is part of learning how the camera sees.

Depth of field

The static image we create may or may not seem in sharp focus throughout. This is known as depth of field. It is referring to which parts of the scene are in “acceptable” focus. The aperture setting controls the range of this good focus area.

Remember that the 3 main things controlling the exposure of an image are the aperture, the shutter speed, and the ISO setting. The aperture controls the amount of light coming through the lens at any instant. How long the sensor is exposed to the light is the shutter speed. And the ISO setting is the sensitivity of the sensor to the light. A side effect of the aperture setting is the control of effective depth of field.

In real life we do not see limited depth of field. Our eyes focus on one small area at a time. Each spot we focus on is in sharp focus. The resulting image our brain paints is that everything is in focus. Try it. Look around where you are now. Then close your eyes and try to remember which parts were out of focus. Spoiler – there aren’t any. We remember it all in focus.

So this is a big disconnect between what we perceive of a live scene and what we record in a photograph. Some photographers see this as a problem if they cannot keep the entire scene in sharp focus. But intentionally making non-subject areas blurry can also be used for artistic effect. Since this is different from how our eyes see, this creates something that stands out. It can change our perception.

But like it or not, it is something that the camera sees differently and we need to learn how to handle it.

Shutter speed

To our eyes, things seem to be either frozen sharply or “just a blur” moving by. Things are usually only perceived as a blur if we are not paying attention to them.

But for the camera, the shutter is open for a certain amount of time and things are either sharp if they are still or blurred if they are moving. The camera does not understand the scene and it is not smart enough to know what should be sharp.

Let me give an example. Say you are standing beside a road watching a car go by. If we care about the car (wow, a new ______; that would be fun to drive) we are paying attention to it and we perceive it as sharp. To the camera, it is just something moving through the frame while the shutter is open. It has no name or value. The photographer has to determine how to treat this motion. What it should “mean”.

So the photographer may pan with the car to make it appear sharp while the rest of the image is blurred. Or the intent might be for the car to be a blurred streak in the frame. Either way, it is a design decision to be made because the camera records movement differently from us.

The lens

Unlike us, our cameras let us swap out a variety of “eyeballs” – the lens. We have a certain fixed field of view. That is why camera formats have a particular focal length designated as the “normal” lens. For a full frame 35mm camera like I use, the “normal” lens is in the range of 45-50mm, because for this size sensor this corresponds to the field of view we typically see.

But most of our cameras are not limited to that. We can use very wide angle lenses to take in a larger sweep of scene. Or we can use a telephoto lens to bring distant subjects close or to restrict our view to a narrow slice. Or we can use macro lenses to magnify small objects. All these things give us a new perspective on the world that would not be possible with our regular eyes. This is another way the camera sees that we need to learn to use.

Mapping to 2D

The world is 3D. Pictures are 2D. It seems obvious. Yet we must be aware of the transformation that is happening.

In the 3D space we move in, we are acutely aware of depth and movement in many axes – length, width, height, pitch, roll, yaw, and others. We use this information automatically to interpret the world. But it is lost when the scene is captured on our 2D sensor.

We sense depth. “In front of” or “behind” come automatically to us. Our camera is not as smart. The camera sensor records everything in front of it as a flat, static image. The scene is mapped through the particular perspective of the lens being used and onto the flat sensor.

An example to illustrate. This is a classic. You take a picture of your family downtown. The scene looks perfectly fine and normal to you, because you intuitively realize the depth and separation of things. It gives you selective attention. But when you look at the picture there is a very objectionable telephone pole poking out of Uncle Bob’s head. You did not pay attention to that at the time because you “knew” the pole was far behind him and you dismissed it. The camera doesn’t know to ignore it. All pixels are equal.


This is fundamental to our cameras. There has to be a light source. The camera sees only light from a source or light that is reflected or transmitted by objects. But being humans, we interpret the real world as objects. They are “there”. They have mass and form and value and color. Not so to the camera. It doesn’t ascribe meaning to a scene. All a camera can record is light. Our fancy sensor doesn’t see a red ball. It detects, but doesn’t care, that there is a preponderance of light in the red band being recorded.

By its very definition – photo-graphy means writing with light – photography is dependent on light. Our modern sensors are marvelous products. We can shoot at very high ISO and make exposures in almost total darkness. But if any image was recorded, there was some actual light available.

Everything in every image we make is a record of light. More than almost any other art form, photography is dependent on light. Photographers must be intensely sensitive to the direction and quality and color of the light sources that are illuminating our scene. Likewise we must be very aware of the objects the light is falling on, their shape and texture and reflectivity and color.

Learning to see, again

Art in general, and photography in particular, is a lifelong learning. We learn to see creatively. We learn to see compositions and design. And we have to learn to see the way the camera sees. This is the way we capture the image we want.

Note, after writing this I found this good article by David duChemin. He is a great writer.


Bad light photo

Maybe it seems silly to talk about light and photography. It seems obvious. But light is one of the things many photographers obsess about, worry about, plan around. Good light, bad light, golden hour, etc.

As photographers we need to need to be very aware of light. We cannot make photographs without light. The light we have at any given time strongly influences the pictures we make. Let’s talk about awareness of it rather than trying to tell you what light you should or shouldn’t use.

“Good” light

Good light. Ah, the holy grail. Many people search for it all the time. I know photographers who will not take their cameras out unless the light is “right”. Sometimes, I confess, I do it myself. You know, its a blizzard out, I won’t bother. The light isn’t right.

This very elitist view is unfortunate, but people come to the attitude honestly, because that is what many instructors teach. They say you have to research a location, find the exact right time of year and angle of light for a particular landscape subject. Then hope the weather cooperates on the one hour window have you allowed yourself to shoot your subject.

And “golden hour”, the prime time for all outdoor photographers. Many people are taught that it is worthless to even try to shoot after the sun has been up an hour and until an hour before it sets. Learn to think different. You are needlessly limiting your opportunities.

If your thing is shooting portraits perhaps you prefer an overcast, soft light day. This makes gentle, even, predictable light for excellent results. No doubt, but how many of those ideal times do you have? And how many good opportunities do you miss because the light is not exactly the way you want?

“Bad” light

Photo instructors teach, or at least imply, that there is bad light that should be avoided. The harsh light of midday is a prime example. It is made to seem that no self respecting photographer goes out to try to shoot when the sun is high overhead. The shadows are harsh and the light is flat and boring. At least, that is what they say.

Or maybe it is a uniformly overcast day with a bright but featureless sky. Terrible we are taught. There is little tonal separation and the sky is flat and boring. You can’t shoot good landscapes then.

Or after sunset when there is no direct light and the exposure times are getting long. That is another time people pack up their equipment to leave.

Or even if you are shooting in midday (shame on you) but you forgot to being your 11 stop neutral density filter to being the light levels down enough to do a 10 second exposure of that waterfall to streak the water like you intend. That must mean the light is bad. Or…


OK. If you have held on this long you will probably get that I’m suggesting that light is not good or bad, it just is. Use the light you have. Embrace it and figure out the best way to use it. In most of the examples I cited above the photographer had a fixed expectation of what they wanted to see and shoot. If the light did not match their expectations, it must be “bad”.

Most of us do not have the resources of, say, National Geographic funding our shoots. If we take a trip to a location we have been wanting to photograph, we can’t just hunker down and wait it out for a week or 2 if the weather is not what we wanted. We have to be flexible and adaptable.

If we get to our location and it is closed for some reason, we cannot change that. But we can find something else maybe even more interesting. Same with the light. Figure out what works right now. What you end up with may be better than what you planned.

Try practicing this flexibility. It is a great creativity exercise. An attitude and practice is what Jay Maisel calls “going out empty“. That is, leave your expectations at home. Just wander around and learn to see things that are interesting. Things the light works for. Things that excite you. In doing this you develop the skill to be able to work with what you have before you. To let the conditions, including the light, guide what you do. But no matter the conditions, to be able to make interesting pictures.

Street photographers are probably better at this than most of us. They have to be adaptable. Light not working here? Move. Can’t find the subject you had in mind? Get interested in what is there. They are used to letting their creativity guide them to good shots.


I’m afraid too many instructors train their students to be internally focused. To have a preconceived idea of what they are going to shoot and to reject anything else. There are certain times when a fixed idea of what you want is required, but for most of us, it does not have to be the normal pattern.

I encourage you to instead be aware of the light, of the surroundings, of the activity or the scenes around us and flow with it. Use your creativity to make something interesting out of what you find rather than coming home disappointed because you did not find exactly what you intended.

Take the photo at the top of this article for example. Midday, flat light, hazy, featureless sky, not what I would usually look for. But I think this works. 🙂

Maybe it is too far of a stretch, but it seems to be an attitude of gratitude. Be thankful for what you have and learn to find surprises that delight everyday. Who knows where it will take you?