With the help of a flash light, you can take some pretty interesting photos during day time. One common way to use a flash is to light up your subject when it is back-lit by the environment. This technique is used mostly on portraits photography but of course you are free to choose your subjects.
These photos were taken a couple of weeks ago at VanDusen Botanical Garden. I separated this set just to illustrate the use of a flash light during day time.
This photo was taken during day time as well, but with manual settings set in my T1i to under-expose the background and the foreground subject is lit up by the flash. It looks almost like this photo was taken at night. So why is this better than taken the same photo at night? Well, at least the camera has no problem focusing during day time, the same may not be true at night.
Again, this photo wask taken at broad day light and the flash really helped bring the details out of the subject.
Same idea here, the background appears darker than how it actually was.
And finally, this tree was totally back-lit and the flash cast light interestingly on the front of the tree.
There are plenty to learn about flash photography, strobist is a good site to read about lighting for photography. The Digital Photography Book Volume 2 by Scott Kelby is also a very practical resource for anyone who wants to learn about lighting techniques.
Do you use the flash light that comes with your camera? Do you prefer an external flash?