Learning photography by reading about it produces a specific kind of knowledge: technically correct, practically inert. You can explain the exposure triangle. You cannot reliably make a well-exposed photograph in a new situation.

The gap closes faster if you start narrower. Most of what you read about camera settings is true. Very little of it needs to be learned before the rest.

The Three Numbers

Every photograph is the product of three decisions:

  1. Aperture — how wide the lens opens (f/1.8, f/8, f/16). A wide aperture (low f-number) lets in more light and produces shallow depth of field: the subject is sharp, the background is soft. A narrow aperture (high f-number) lets in less light and keeps more of the scene in focus.

  2. Shutter speed — how long the sensor is exposed (1/1000s, 1/60s, 1s). Fast shutter speeds freeze motion. Slow shutter speeds blur it. Slower than about 1/60s while handholding produces camera shake.

  3. ISO — the sensor’s sensitivity to light (100, 800, 6400). Higher ISO means you can shoot in dimmer light, but the image accumulates grain (digital noise). Lower ISO means less noise, but you need more light or a slower shutter or a wider aperture to compensate.

These three numbers are linked. Change one and you have to compensate with one or both of the others to maintain the same exposure. This is the exposure triangle, and understanding it is genuinely the foundation of everything else.

What to Ignore First

There are entire books written about:

  • White balance
  • Picture profiles and color science
  • Autofocus modes and tracking
  • Metering modes
  • Custom function assignments
  • In-camera HDR and long exposure noise reduction

All of these matter eventually. None of them matter more than understanding aperture, shutter speed, and ISO, and none of them will make sense until you do.

Set white balance to auto. Set metering to evaluative (or matrix, or multi — the same thing with different brand names). Set autofocus to single-point. Leave the rest alone.

A Single Exercise

Set your camera to Aperture Priority mode (Av or A on the mode dial). Set your aperture to f/4. Shoot something. Look at what the camera chose for shutter speed and ISO. Now change the aperture to f/8 and shoot the same thing. Look at what changed.

Do this for one afternoon. You will understand aperture more from this exercise than from any amount of reading, including this post.

Then repeat the exercise in Shutter Priority mode (Tv or S), setting the shutter speed and observing what compensates.

Everything else in camera operation is variation on this.

When to Expand

The right time to learn something new about camera settings is when you encounter a specific problem that the thing you know cannot solve:

  • Subject is blurry when you want it sharp: shutter speed problem.
  • Background is distractingly sharp when you want it soft: aperture problem.
  • Image is noisy in a way you find unacceptable: ISO problem, or light problem.
  • Colors look wrong in mixed lighting: now white balance is worth learning.

Learn in response to problems. The alternative — learning everything before you encounter the problem it solves — produces knowledge that does not attach to anything and fades fast.