Understanding exposure makes you a better photographer

This is my first post in this “How to craft better photos” Series. I will be talking about the basic concepts of photography exposure.

                              Taking proper exposed images matter!

Today the digital cameras can handle exposure very well in automatic and semi automatic modes, but understanding exposure properly can certainly help to improve your photography.

Let's start by thinking about what's happening with light when you take a picture. The light passes through the lens and then through the shutter before it arrives at either a sensor or a frame of film. The camera's lens and shutter control how much light gets to that sensor or film frame.

Exposure is all about how much light go into the camera sensor or film.

Too much light, and your photos will be washed out, too little and they will be too dark.

Overexposed Image	Proper Exposed Image	Underexposed Image

5 Reason to have control of the exposure

1. If you overexposed (too much light) you will end up with blown highlights and you can never recover details in these areas of the image, never.
2. If you underexposed (too little light) same happens, there is not data recorded in dark areas and you can never recover them.
3. Poorly exposed images have low contrast
4. Poorly exposed images don’t have good color saturation
5. Light meter in cameras can be (and the often are) fooled by certain lighting conditions

Therefore, is a most to have an understanding of exposure before you press the shutter!

What Affects Exposure?

There are three things related to exposure.  The relationship between aperture, shutter speed and ISO is what make an exposure. Those three are closely connected, and that connection is the basis of every photograph.
Two of those involve how much light comes into the camera; the third is the sensitiveness to light of the film or sensor of your camera.

• The shutter Speed
• The Aperture
• The ISO (light sensitivity)

Understanding Exposure – The Shutter Speed

To understand exposure , you need to understand shutter speed. The camera’s shutter controls  how long the the light coming through the lens gets to hit the media; film or sensor.

The shutter works as your eyelid.  It is normally closed, when you press the shutter , it open for a fraction of second to allow the light to get the media. Controlling the shutter speed means controlling the time the eyelid is opened.

The longer it stays open, the more light enters. If it’s open for too long, the photo will be overexposed. Not open for long enough and your photo will be too dark.

Understanding Exposure – The Aperture

The other part of the exposure equation is the aperture.  What the heel is that?

To understand exposure you need to know what the aperture is and  does.  As with shutter speed, the aperture is also a way of controlling how much light enters the camera.

The aperture is an adjustable hole in the lens. It can open to allow more light in. Or it can close to become just a tiny hole, stopping so much light from entering.  It behaves as your eye iris.

So aperture and shutter speed work together to create an exposure. There is just one combination between the shutter speed and the aperture that will resulted in a proper exposed image.

Therefore, if you have a slow shutter speed (to let more light in) you have to close the aperture to compensate. And visa versa – if you have a fast shutter speed (letting less light in) you have to open the aperture to allow in more light to compensate.

Understanding Exposure – The ISO

There is one more key element in the equation, ISO which refers to the light sensitivity of the sensor (or film) inside the camera.  The lower the ISO, 100 for example the more light we need to get the proper exposure.  The higher the number, let say 800, less light we need.

Since we need less light with a higher ISO, you might be tempted to use a high ISO all the time, Be Careful, as we go up in sensitivity, we tend to lose color saturation and gain noise, which gives images a grainy look (speckling effect on photos).

So..

So it's our job to manage exposure to get the sharp, clear photos we want. The key thing to remember is that the three elements—aperture, shutter speed and ISO—are always linked. For photographers it's a balancing act, and so we're always adjusting the shutter speed and aperture for the right exposure and the effect we want.

Of course, you can bypass all of the above simply by setting your camera for auto or program mode and letting the built-in computer do the work. Still, understanding the relationship of aperture, shutter speed and ISO will give you a greater understanding of how to take control of your photography.

Remember :

Shutter Speed + Aperture + ISO = Proper Exposure

Homework

Homework for this lesson is fairly simple. Set your camera to manual mode.  Keeping always the same ISO setting. Take a photo.  Then, change one of the elements, aperture for example to a higher setting, and take a photo.

How the exposure change? It is lighter or darker?

Now change the other element (shutter speed in this case) to compensate the first element changed - to a faster shutter speed.  Now you get same exposure than the first taken photo.  Why? Because you set the relationship between aperture and shutter speed to the same as the original photo.

I will love to see comments about your experiences…    You may share them with us in the comment area.    You may subscribe to our RSS too!

Read the Full Series

This post is part of a series on “How to craft better photos” . It will be all the more powerful if you taken in context of the full series which looks at 5 points of how to improve your photography and do it in a creative way.  Start reading this series here.