This is the ninth article in a series on "understanding your camera" that I am writing as I teach camera basics and camera operation to my children.

Let me start with a definition of "depth of field". Wikipedia defines "depth of field" as If the entire image is sharp (ie, all in focus), it has a large depth of field. If an image has the foreground sharp, while the background is blurred, it has a small depth of field.
A small depth of field is also referred to as "shallow focus", and a large depth of field is also known as "deep focus".

The term "depth of field" is often abbreviated as "DOF".



There are a number of factors that affect the depth of field in a photo.

• Distance between camera and subject
  Shorter distance = less DOF; longer distance = more DOF.
  
  The further the camera is away from the subject, the more DOF you will get.
  This is one of the reasons macro photography is challenging. With very short distances between the camera and the subject, the depth of field tends to get very small.
• Focal length
  Longer focal length = less DOF; shorter focal length = more DOF.
  
  Longer focal lengths mean less DOF, which is one of the reasons why longer length lenses can be great for portraiture photography.
• Aperture
  Larger aperture = less DOF; smaller aperture = more DOF.
  
  Opening up the aperture reduces the DOF, while stopping down the aperture increases the DOF.
  A "fast" lens with a larger maximum aperture (say, f/2.8 or larger) allows a smaller depth of field to be achieved than a kit lens with a maximum aperture of f/4.
• Format size (ie, sensor size in a digital camera, film size in a film camera)
  Larger sensor = less DOF; smaller sensor = more DOF.
  
  Full-frame DLSR cameras provide smaller depth of field than a crop-sensor DSLR.
  Point-and-shoot cameras, with their tiny sensors, typically struggle to provide a small depth of field. (This is due to the format size affecting the circle of confusion, but that is a complex topic that I will leave for a future post.)

Here are some photos demonstrating different depth of field by varying only the aperture. Both photos were taken from exactly the same location. The first photo shows a very short depth-of-field due to the use of a large aperture, which causes the (distracting) background to be completely blurred.
The second photo shows a much larger depth-of-field due to a much smaller aperture.

very short depth-of-field due to lens being wide open at a large aperture of f/2.8

Canon EOS 50D, 24-70mm f/2.8L @70mm, 1/400 sec, f/2.8, ISO100

larger depth-of-field due to lens being stopped down to a small aperture of f/22

Canon EOS 50D, 24-70mm f/2.8L @70mm, 1/30 sec, f/22, ISO640

Shallow depth of field will draw the viewer's eye to a specific part of the image, typically desired in portrait photography.
Conversely, deep depth of field ensures all components of the image are in focus, which is typically desired in landscape photography.

Understanding the factors that affect depth of field allow you to be aware of the impact of varying any of those factors, and thus have more control over the depth of field in your photos.

Because depth-of-field is one of the key aspects I like to control in my photography, most of my photos are taken with the mode set to aperture priority. This allows me to choose the aperture, rather than allowing the camera to select the aperture.

Because the old cities and buildings of Holland appealed to me while on holidays there mid-last year, I have enjoyed looking through the black-and-white photos from this project, and thought it worthwhile mentioning Jan-Willem's Cities of Holland project.

The Project
Cities of Holland is a project of the Dutch photographer Jan-Willem Eshuis. The idea of Cities of Holland is to take a unique photo of all cities in the Netherlands that have (or had) city rights. City rights are a phenomenon in the history of the Netherlands, Belgium and Luxembourg. The rights where given by a liegelord (for example a duke) to a settlement he owned. The rights gave certain privileges that settlements without those rights didn't have. Some examples of city rights are the right to build a city wall, have a market or the right to charge toll.

In the Netherlands there is a total of about 194 cities with these city rights. The goal is to take a photo of each of these cities with a characteristic building or on a characteristic spot of that city.

one of the photos from the Cities of Holland project: Skyline of Deventer

photo by Jan-Willem Eshuis, used with permission

Why?
The idea of this project is based on the Streets of the World project. In this project the Dutch photographer Jeroen Swolfs is traveling around the world to make a photo of every capital in the world. His project is taking five years and inspired me to realize a similar project.

About Jan-Willem Eshuis
Jan-Willem Eshuis is a Dutch amateur photographer who's working as a CTO at a Dutch media company named NLbuzz. In his free time he loves to take photo's of all kind of objects. He used to take pictures with his Nikon SLR D50 and D60 camera but in december 2010 he bought his Leica D-Lux 5.

For more information on the Cities of Holland project, check out the Cities of Holland website, facebook page, flickr stream, or twitter page.




If you have never seen The Little People Project, it is definitely worth checking out. slinkachu is a UK-based artist who does street art installations, and photographs them. However, these art installations are tiny!
The recently-posted Dead Leaves series is a great example of the type of work in The Little People Project. The Fantastic Voyage is another of my favourites.

More photos from this series are available on The Little People Project website and on slinkachu's flickr stream.



Lisa Bettany has posted 6 New Year's Resolutions Every Photographer Should Make in 2012.
Every photographer should read her list and add those resolutions to your list!



Year-long exposure of Toronto skyline, taken with a pinhole camera, has produced an interesting photo. Michael Chrisman installed the camera at the beginning of 2011, and pulled it down on 31 December 2011. I particularly like the interesting trails left by the sun as it moves across the sky throughout the year.



In another year-long photography project, Eirik Solheim has taken a photo out of his window every half hour. He then used a selection of 3888 of those photos, and using a 1-pixel-wide strip of each, created a different kind of time-lapse photo. Have a look at his One Year in One Image blog post for the resulting photo.
If you are interested in the technical background on the process used to capture these photos, have a look at this blog post.

Here are some photos from another KAP session in Albany - this time at Emu Point beach.
We were at the beach in the early afternoon, and the seabreeze was blowing well, so I thought I would try flying my kite to capture some more aerial photos with the GoPro Hero2 camera.
Once the kite was airborne, and the camera rig was attached, I proceeded to let out more line, and captured some photos using the camera's built-in intervalometer.

looking north-west at the boat pens

Emu Point, Albany, Western Australia
GoPro HD Hero2 (suspended from a kite)

However, as the kite went higher, the wind got stronger, causing the kite to dart around the sky, with the camera rig swinging wildly through the sky.

We spent a week on holidays in Albany (south-west of Western Australia) in late December. While in Albany, I lifted my recently-purchased GoPro Hero2 camera aloft with my kite.

My first KAP session with the GoPro Hero2 was at Middleton Beach, and while the wind conditions were great, the lighting wasn't ideal, as it was getting a little too dark. The GoPro Hero2 seems to handle the low light conditions quite well, and I was quite happy with the results.

Here's a shot of the sunset over Mount Clarence, with Middleton Beach in the foreground.

sunset over Mount Clarence to the south

Middleton Beach, Albany, Western Australia
GoPro HD Hero2 (suspended from a kite)

Three baby quails hatched in our aviary a few days ago.
While we have had plenty of baby finches over the years, the baby finches will only venture out of the nest when they are adult-sized.

In contrast, baby quails hatch on the ground, and are immediately mobile, scampering around on the ground, and hiding underneath their mother's wings.
They are a lot of fun to watch, and I took the opportunity to take some photos of them this afternoon.

three baby quails

Canon EOS 50D, 70-200mm f/4L @200mm, 1/800 sec, f/4, ISO500

snuggling up to mother

Canon EOS 50D, 70-200mm f/4L @200mm, 1/1000 sec, f/4, ISO500

staying close together

Canon EOS 50D, 70-200mm f/4L @200mm, 1/1000 sec, f/4, ISO500

checking out the surrounds

Canon EOS 50D, 70-200mm f/4L @200mm, 1/1250 sec, f/4, ISO500

exploring

Canon EOS 50D, 70-200mm f/4L @200mm, 1/500 sec, f/4, ISO500