Understanding Exposure

30 Days of Smartphone Photography day 12

In this post I will take you through what I know about the basics of exposure. I guess this post is better aimed at digital camera users who would like to learn more about the creative setting on their cameras, but some of these ideas still apply to your smartphone camera too. 

IMG_0639There are three important settings on your digital SLR camera which effect exposure. Each of these settings plays an important role in how your camera processes light to create an image.

If you change one element, it will effect the other two.

Understanding the exposure settings

  1. ISO - how sensitive your camera is to light
  2. Shutter Speed -how long the shutter stays open
  3. Aperture - how big the hole is which lets light in to capture the image

By adjusting these settings you can ensure that the right amount of light is being captured to create a correctly exposed image.

Understanding how each setting effects the others took me a really long time to get stuck in my head. I don't know how but I used to get aperture and shutter speed mixed up and constantly had to go back and read and re-read tutorials.

One of the best things I read which really helped (besides practice, practice, practice!) was a metaphor on Digital Photography School about a window.

Think of your camera as a dark room which has a window with shutters you can open and close. The wider you open the shutters (aperture) the more light will be able to come in.

Shutter speed can be thought of in terms of leaving the window shutters open for a short or long period of time. The longer you leave the windows open the more light will come in. In this way, aperture and shutter speed are quite similar.

ISO can then be thought of like a pair of sunglasses. If you are in the room and you're wearing sunglasses you will be less sensitive to the light entering the room. Or, if you take the sunglasses off you will be more sensitive to the light. ISO allows you to take photos in lower light settings by increasing your camera's sensitivity to light.

The ever confusing aperture

Aperture can be extra confusing because of the way the size of the hole is measured. A smaller aperture (f-stops like f/4 or f/5.6) actually denotes a larger hole (more light), and hence a shorter shutter speed is required. F-stops like f/16 or f/22 denote a smaller sized hole which would require a longer shutter speed to access the same amount of light.

Aperture also allows for depth of field (DOF), which is best explained with images.

A shallow depth of field which means a wide aperture (this was shot at f/4) creates a beautiful soft background blur (known as Bokeh).


IMG_0724If you want to bring more attention to a particular detail in your photographs use a wide aperture (smaller f-stop) to create an appealing blurry effect in the background.

A greater depth of field (smaller aperture, larger f-stop number) will keep most of the image in focus as shown below. This was shot at f/16. Smaller aperture settings are ideal for landscape photography where you want the entire image in focus.

IMG_0989Exposure on your Smartphone

Unfortunately, besides ISO you can't control these settings on your smartphone camera. You can however adjust the exposure level, and by tweaking the ISO as well you are more likely to capture better image.

Unless you are taking a very close up shot its impossible to get Bokeh in your smartphone photos. Smartphone camera's aren't designed to have the settings meddled with too much, but you can still capture beautiful shots by learning to use the settings you can change.

With apps like Photo Editor, or even Instagram you can create your own DOF and similar effects to create an awesome shot.

Here's a close up shot on my phone camera showing some background blur, and the same shot from further away completely in focus.



Like I said earlier, practice, practice, practice! It really does help to just get out there and take photos. Practice using the creative settings on your dSLR (Tv, Av or M), and experiment with the aperture to better wrap your head around it.

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