This is the first article in a series that I am writing as I teach camera basics and camera operation to my children, in particular to my 11 year old son who wants to buy his first DSLR. My children have been using cameras for a while (with some good results), but typically use full-auto mode, or rely on me to adjust the settings for them.

I thought it would be worthwhile to write a series of blog posts on this subject, to help other people who might be interested, and because one of the best ways to ensure you understand something is to try to explain it to others.



The exposure of a photo determines how dark or light a photo will be when it is captured by your camera's sensor (or film, if you are old-school).

There are three factors that affect the exposure of a photo:

• lens aperture
• shutter speed
• ISO

I'll briefly describe each of these (more detail on each in future blog posts), and how they work together to determine the exposure.

On Saturday, the third annual Scott Kelby Worldwide Photo Walk took place. Two walks had been organised in Perth, with nearly 50 walkers for each.
I participated in one of the walks in Perth, and took my two oldest children (aged 10 and 11) with me, both with cameras of course ;-)

It was fantastic weather for a photowalk, and we enjoyed ourselves. Many people in Perth were wondering why there was a sudden influx of cameras in the city, with some interesting reactions, including a number of pedestrians insisting on posing for the cameras.

Photos from other participants in the various photowalks in Western Australia yesterday, as part of the Worldwide Photo Walk, can be seen in this flickr group.

Here is a selection of my photos from the walk - the full set can be seen in this photo gallery.

I see you!

Perth, Western Australia
Canon EOS 50D, 35mm f/2 @35mm, 1/100 sec, f/4, ISO100

reflections

Perth, Western Australia
Canon EOS 50D, 35mm f/2 @35mm, 1/400 sec, f/5, ISO100

Colourful autumn leaves provide an interesting background to this closeup of a seedpod hanging from the branch of a Liquidambar styraciflua tree.

seed pod

Burswood, Western Australia
Canon EOS 50D, 35mm f/2 @35mm, 1/200 sec, f/3.2, ISO100

seed pod hanging around

Burswood, Western Australia
Canon EOS 50D, 35mm f/2 @35mm, 1/100 sec, f/5.6, ISO100

50mm prime lenses are quite popular - and this is apparently because a 50mm lens provides a similar focal length to the human eye. Most lens manufacturers sell a cheap and fast 50mm lens, and I have previously reviewed the Canon EF 50mm f/1.8 lens, which retails for just USD$100.

My primary camera is a Canon 50D DSLR, and due to the size of its APS-C sensor, it has a 1.6x crop factor. This means a 50mm lens on an APS-C camera body has the same field-of-view as an 80mm lens on a full-frame camera body (ie, 50mm * 1.6 = 80mm).

While I like the Canon 50mm f/1.8 lens, I've found a 50mm lens on an APS-C camera body just a little too long, and started looking at slightly wider alternatives.

To achieve the equivalent field-of-view with an APS-C camera body that a 50mm lens has on a full-frame camera body, a lens with a focal length of around 31mm is required.
In the Canon lens range, there are a few options near this focal length, including various lenses at 24mm, 28mm and 35mm.

After keeping an eye on second-hand lenses on eBay, I managed to win a Canon EF 35mm f/2 lens at a pretty good price.
A 35mm lens on an APS-C camera body results in almost same field-of-view as a 50mm lens on a full-frame body - giving the same field-of-view as a 56mm lens on a full-frame body.

Canon EF 35mm f/2 and Canon EF 50mm f/1.8 II lenses

In the few weeks since buying the 35mm lens, it been the primary lens on my camera! I've been enjoying the focal length, and find it to provide a more natural field-of-view on my 50D than the 50mm lens.

I have already posted a few photos taken with the 35mm lens, and I'm intending to write a more comprehensive review of the 35mm f/2 lens in the near future.


Update (November 2010): I have now published a review of the Canon EF 35mm f/2 lens.

Gum leaves, back-light by the sun.

gum leaves

Burswood, Western Australia
Canon EOS 50D, 35mm f/2 @35mm, 1/320 sec, f/3.2, ISO100

Some yellow lichen provides a bright contrast against the dark bark of a branch. Taken while testing out the minimum focussing range of the Canon EF 35mm f/2 lens.

a splash of yellow

Burswood, Western Australia
Canon EOS 50D, 35mm f/2 @35mm, 1/200 sec, f/4.5, ISO100

I received a parcel in the mail yesterday from Hong Kong, containing a brand new product from Phottix, the Strato 4-in-1 Trigger.

It's a 2.4GHz, 4 channel wireless remote that can be used as a wired shutter release, wireless shutter release, or a wireless flash trigger. Not only that, but it also supports pass-through ETTL to any flash or remote mounted on the hotshoe on top of the transmitter.

Phottix Strato 4-in-1 Trigger

The photo above shows how it can be used - with the Strato transmitter on the hotshoe of a Canon 350D, and a Canon 580EX flash on the hotshoe of the Strato transmitter.

The release date for the Phottix Strato 4-in-1 Trigger hasn't been set, so I can't say too much about it just yet, but stay tuned for a detailed review of it in the near future!