Wednesday, May 13, 2015

Photography 101: Exposure Basics | Raleigh Family Photography

As a newborn and family photographer, a lot of people have asked me for help with some camera basics.  I love to teach, especially when it's something I am passionate about.  I find that many people struggle with their camera when they get their first DSLR.  The camera, with all the bells and whistles, is really only a tool.  Understanding how photography (and your camera) works is the first step toward taking amazing photos.  This series is intended to be a quick overview of camera basics.  The first part in this series is about exposure.

"Carboniforous." One of my all-time favorite macro images, he
can be found in the 2014 Professional Photographers of America
Loan Collection.

Exposure is the backbone of photography, because photography is all about light.  Exposure is the amount of light per unit area which reaches the camera sensor on a digital camera or the film on a film camera.  It is considered to be too high when the image loses detail in the highlighted areas of the image, often known as “blown highlights”.  Conversely, exposure is considered too low when you lose detail in the shadows of the image.  Underexposure generally is easier to recover on a digital camera than overexposure.

The exposure is 'technically' correct when the recording is completely within the dynamic range of the camera.  However, that’s only a piece of the puzzle.  The reality is that the exposure is correct when the photographer reaches their desired results.  Sometimes a photographer uses blown highlights or shadows details purposefully, making ‘correct exposure’ a liquid term.

Increases and decreases in exposure are measured in ‘stops’ of light.  Moving a stop up will double the amount of light, while stopping down your light will cut it in half.  You control the amount of light coming through to the sensor by way of your shutter speed, ISO and Aperture.  Changing one of these elements will change the amount of light reaching your camera.  However, each change comes at a price.  Balancing each of these elements is the key to creating a great exposure.


Shutter speed is simply the speed at which your camera shutter opens and closes.  Another way to think about it is how long the light is allowed to reach the sensor.  A slower speed can lead to camera shake unless the camera is balanced on something like a tripod.  A faster speed can underexpose your photo.  A general rule for hand holding a camera is to keep the shutter speed ‘faster than the focal length of your lens’, but not slower than 1/125 of a second.  So if you have a 200mm lens, keep the shutter speed at least 1/250.  Shutter speeds are always measured in seconds and fractions of a second.  Here is a a range of shutter speed in full stops from more light to less light.

Slower (more light)   1    1/2    1/4    1/8     1/15    1/30    1/60    1/125    1/500   Faster (less light)

You can see that this image isn't as sharp as the others.  I did not
have a tripod at hand and camera shake was a problem here.


The aperture is the opening and closing of the aperture blades within lens, which act similarly to the pupil of your eye.  This controls how much light is allowed through to the sensor.  When photographers say they are ‘shooting wide open’, they are referring to a wide open aperture (which is, conversely, a smaller f-stop).  Aperture is measured in f-stops, which represents the stops of light.  Aperture is one of several elements that control depth of field.  Here is a range of shutter speeds in full stops from more light to less light.

Wider (more light)   1.4     2.0     2.8     4.0     5.6     8.0     11     16   Smaller (less light)

This is a shallow depth of field with a wider

Narrowing down the aperture helped put
more of this cicada in focus (I would keep it
wide for portraits of children, however)


ISO is the measurement of sensitivity to light either by film in a film camera or the sensor of a digital camera.  Increasing the ISO and the sensitivity of the recording medium (film or sensor) increases the amount of grain.  However, a low ISO can cause underexposure. Here is a a range of ISO in full stops from more light to less light.

More sensitive (more light)   3200    1600    800    400    200    100    50   Less sensitive (less light)

As much as I love his eyes, this image struggles with grain
and a wide open aperture. Look particularly around his legs.


Exposure is all about three interrelated parts.  These three parts create an image that is unique to you.  Exposure is very individual, but nailing your exposure is the difference between a fantastic image and a poor to mediocre one.  If you're still having some trouble understanding how they work together, think about this analogy:

A big thank you to my husband for this one!

Now that you know what it is, it's time to put it to the test.  In the next Photography 101 article, I'll discuss how to change your exposure settings using your various camera settings.

An exposure cheat sheet for you.
I love hearing from my readers.  Please feel free to leave a comment if you have any questions or contact me.  If this post inspires you to take some photos, send them my way, I'd love to feature you on my Facebook page!

1 comment:

  1. great explanation, where did you take the info?i have an interesting tutorial also, here, you can read it!enjoy