How it works, when to use it
Most Nikon D-SLRs have a built-in flash for providing light in dim conditions, and all Nikons can use external flashguns
for more creative lighting. But the quality of the results you get from flash can be disappointing, and it can be difficult to get the strength right and balance it with the ambient light.
Flash is also surrounded by jargon – the more you get into it, the more there is to know and the more daunting it becomes! So here’s our beginners’ guide to how flash works and how to get the most from it.
How flash works
Flashguns fire a very brief, intense burst of light. Its duration varies according to the flash type, but it might typically be in the region of 1/500-1/1000 sec – though it will be a lot shorter at lower power settings.
This burst of light comes from an electrical charge stored in the flash head and then released in an instant. One the flash has fired, it typically takes a couple of seconds for the batteries to power up the head again. This is the ‘recycle time’.
Why is flash harsh?
On-camera flash rarely produces good results on its own. The light is coming from a small source, and this produces harsh shadows. Also, the intensity falls off with distance, so the further away your subject, the dimmer the flash. If you shoot a person against a distant background, they may be correctly exposed but the background will be dark.
This does give flash a bad reputation. However, there are ways you can use flash to get much nicer results and, using external flash, you’re able to get lighting effects you couldn’t achieve any other way. We’ll look at these techniques next month, but this time we’ll discuss how flash works and what makes it different to ambient light.
On-camera flash has a bad reputation, but there are ways to avoid the harsh shadows and get perfectly-lit shots