- from Wikipedia
What this means
The above statement can be somewhat confusing to the unseasoned photographer – basically, DOF is how large of a space is available in your photograph for your subjects to be in focus. This is achieved by manipulating the camera’s Aperture or f-stop. The smaller your f-stop the smaller the DOF will be – coincidentally, the greater your f-stop the greater the DOF will be. In layman’s terms – the background is will be blurrier with a smaller f-stop and sharper with a larger f-stop.
Shallow Depth of Field
The following examples are all examples of a shallow depth of field. Shallow depths of field are helpful for providing isolation of your subject from the background. The smaller the f-stop, the more isolated your subject will be. Note, depending on your lens, using the smallest f-stop available can result in severe loss of sharpness – because of this, it is always good practice to use a larger f-stop in situations where you don’t need the absolute greatest amount of light for exposure.
As you can see above, these images all use a small f-stop. The range of these images is from f/1.4 to f/2.0 which aids in the isolation of the subjects. You can also see that the third image isn’t super sharp. This is because the lens I used isn’t amazingly sharp at f/1.4 – this is a limitation of the lens itself, your results will vary.
Deep Depth of Field
The following examples all demonstrate a deep depth of field. A deep depth of field is the best way of showing the most detail in a scene while providing the best possible sharpness. This can be achieved by increasing your f-stop. I typically shoot scenes like landscapes at f/8.0 to f/16 to ensure optimum sharpness.
The images above all have f-stops ranging from f/8.0 to f/16 – as you can see, everything is in focus in all of these photos. Large f-stops are not only for landscapes, use your creative mind to choose when best to use a larger f-stop.
Why do I need to know this?
In the art of photography, depth of field plays a major role in the final product. In fact, DOF is one of best ways to directly manipulate the photo without doing any postprocessing. Opening up your aperture by selecting a small f-stop lets more light into your camera – as a result, the background is often blurry which isolates your subject. In portraiture this means that you are only seeing your subject, and are not being distracted by an obtrusive background.
I’m not saying portraits should only be shot with a shallow DOF. Sometimes choosing the shallowest depth of field can be very distracting; For example, some lenses can achieve f-stops as low as f/1.0 – using an f-stop this low can result in the tip of your subjects nose not being in focus, which is weird. Choosing an f-stop of f/2 or higher can help minimize the possibility of your subjects nose and ears being out of focus, and still provide you with a beautiful out of focus back drop.
F-stops aren’t all about controlling depth of field. Using a smaller f-stop opens up the aperture of your lens, allowing more light into your camera. Allowing more light into your camera allows you to use a faster shutter speed indoors on darker days. This helps you to avoid having to use a tripod.
What should I take away from this?
I would hope that from this little tutorial you will take away a greater understanding of what DOF means, and how it can be manipulated. Manipulating your DOF directly influences the end result and is, in my opinion, the best way of controlling your image in a striking manner. The next best way is manipulating your framing at the time of shooting – which I will get into later.
If you would like some more information, feel free to send me an e-mail – subject: Depth of Field Tutorial.
