There are two types of photographers when it comes to a discussion about exposure. One type believes that they know all that there is to know about exposure, and the others think it is a subject way too complicated to be bothered about.

No matter where you fall in the spectrum, I am sure you agree that to do anything well, you need to be thorough with the basics (I apologize for quoting your eighth-grade math teacher). Well, exposure is the basic building block of good photography.

I think I have made my point here, so let’s proceed to answer the burning question– what is camera exposure?

What is camera exposure?

Exposure is usually thought of as the brightness of the photograph that you just took. And that is absolutely incorrect. While the brightness (or darkness) of the picture is affected by the exposure, it is not exposure.

Exposure is the amount of light that actually enters the lens of your camera. Now you see the difference?

What is underexposure, and what is overexposure?

A photograph, as I have established in previous articles, serves the purpose of capturing details. As a rule, a picture with hardly any details is considered (for the most part) to be useless. This is where underexposure and overexposure play a role.

Underexposure occurs when a photograph is too dark. The photograph, in this case, appears to be mostly black and you can hardly make out any details.

Overexposure is the other extreme where a photograph is too bright to see any details in it. A major portion of the picture is just white, which obviously would not make it the best photograph. Unless, of course, there was an artistic reason to do so, but I have only seen a handful of professional photographers succeed in doing that.

What is the best level of exposure?

Either way, over or underexposing your photograph is one of the easiest ways to ruin a perfectly good picture. Most photography professionals and enthusiasts prefer to have a ‘mid-point’ value. You could adhere to this, but I would advise against following it religiously. As with everything, it is merely a guideline and not a rule.

The “best” level of exposure is simply the level at which you believe that the photograph you took looks its best.

What camera settings affect exposure?

Many people prefer to leave the camera setting for exposure on automatic, and the camera does a fantastic job by itself. However, it is frustrating when you do not have complete control over your picture. This is where all the confusing-looking knobs, buttons, and what-not on your camera come in handy. If you learn to use these tools that you have paid some hard-earned cash for, you would be well on your way to taking amazing photographs.

When it comes to exposure, three settings can be used to adjust it:

  1. Aperture
  2. Shutter Speed
  3. ISO

While we explore these three settings in detail, it is essential to remember that while aperture and shutter speed are the ones designed to adjust exposure and ISO should be used as a last resort or for any inexplicable artistic urges you may have.

Aperture

Aperture is simply the hole in your lens. If you remember being fascinated by how the blades of the lens open and close that hole as a child, you know exactly what I am talking about.

The aperture controls how much light enters the camera and consequently has a significant impact on the amount of exposure. The wider the aperture, the more light enters your camera, and the higher the exposure of the photograph will be.

Adjusting the aperture settings make it easy to capture an image exactly the way you want it.

For example, if you are taking a picture of the night sky, you would want to use the widest aperture possible, or else your image will be underexposed.

If you are taking a landscape photograph on a sunny day, you would want to use a smaller aperture so that the picture is not overexposed.

Shutter speed

Shutter speed is the time your camera takes to capture a photograph. For most cameras, this value is somewhere around 1/60. If you have got a more professional camera, it is possible to select from a very wide range of shutter speeds.

From a logical standpoint, we know that the longer the shutter is open, the more light enters the aperture and so the exposure of the photograph will be higher. So slow shutter speeds increase the exposure level while fast shutter speeds reduce it.

In the hypothetical example situations we took above, we would use slow shutter speed to capture the night sky and a fast one for the landscape.

ISO

This is one of my least favorite ways to increase the exposure of a picture, and I would recommend it only in emergencies. ISO has nothing to do with the light entering the camera. It only brightens up the picture after you have captured it.

The more you increase the ISO, the more exposure your photograph will receive. But there is a catch– the more you increase the ISO, the more grain or ‘noise’ will be present in the picture. Again, artistic tendencies aside, noise is a big no-no for a high-quality image, and therefore, ISO should be used only sparingly.

Of course, I do not expect you to start using all these tools like an expert after you read this article, and you should not expect it out of yourself either.

It is possible to have a very high degree of control over the exposure of your photographs, but as with almost everything, it comes with practice. More likely than not, you will enthusiastically adjust your aperture and shutter speed and mess up a perfectly good shot. But don’t fret it.

Experience is the best teacher.

Besides, if all else fails, then use the trusty old Photoshop. After all, there is hardly any problem it cannot fix.