While, at the core of things, all flashes do the same thing (all flashes provide light) they are not created equal.
Some flashes provide more/brighter light and allow more control of the light being transmitted by them.
I recently used a Canon G-12 and, while I liked the camera, I found myself wishing that the flash that was built into the camera allowed more control of the light being transmitted by the flash.
The G-12 has a hot shoe that would allow the photographer to use an external flash.
An external flash would have been the solution to what I saw as the shortcomings of the built-in flash of the G-12.
I have a few different flashes, but there is one that I consider my ‘everyday, knockin’ around flash”. This flash is small, and easily carried with me all of the time and, while very basic, is much more versatile than the flash built into a camera. This flash would have been perfect to use with the G-12 and was used to make the picture that accompanies this post
Along with the flash, I have a sync cord which allows me to take it off of the camera to change the direction of the light and a Wein Safe-Synch which allows me to attach the flash to cameras without a flash synch terminal and doubles as a protector for the camera if I use a “non-digital” or incompatible flash.
Here are the links to the items. The flash I own is no longer made, but the manufacturer makes something similar. I highly recommend that you buy these items from a store where you can test the setup before you leave. Bring you camera into a store, find a patient sales person and makes sure everything works before you buy anything.
***Many camera manuals state that the use of an off brand, or incompatible, flash may damage the camera***
Sync cords–Paramount Sync Cords for Professional Digital and Flash Photography
Wein Safe-Sync—Wein Safe-Sync Hot Shoe to Hot Shoe (SSHSHS) 990-560 B&H Photo