Lighting can be one of the most challenging aspects of photography, and yet it is so key. An external flash unit is one of the most effective ways of ensuring a correct exposure, but setting them up and usage them correctly is again a major challenge.
With this tutorial we've really tried to go in-depth and leave no stone unturned. The flash photography tips in this post run through some of the most effective techniques for using your external flash unit, the most useful accessories, set-ups and more.
Specifically, we'll cover: Off-camera flash; How to replicate studio lighting with two flashguns: Bounce flash techniques; White bounce cards; Using flash diffusers; and Wireless flash.
The biggest weakness of built-in and auxiliary flashguns is that the quality of light they emit is pretty unimpressive. Because the flash is a high-intensity light source that originates from a relatively small area close to the lens, it yields flat, uneven lighting that creates deep, hard-edged shadows.
It can also eradicate fine textures and contours, bleach out skin tones and cause red-eye - all of which makes for particularly disastrous portrait, wildlife, macro and interior shots.
Larger flash heads aren't quite as bad because they spread light out over a slightly wider area, but the results are still unsatisfactorily harsh.
This type of lighting, which hits your subject straight from a flashgun, is known as direct flash photography. Although direct flash photography usually looks artificial and ugly, it can generate terrific effects when used shrewdly.
Most of the time, however, you'll need to minimise the gremlins.
Flash photography tips: off-camera flash
The key to improving the quality and flexibility of flashgun lighting is to enlarge and soften the light source, and fire it at the subject from a more natural direction.
To accomplish the latter you need to completely separate the unit from your camera using a hotshoe adapter and sync cord. This will enable you to position your flashlight far more suitably and creatively. It will also give your subject a sense of depth and eliminate red-eye.
Nikon and Canon both make that flash guns that preserve full TTL balanced flash metering and power output. Nikon offers the one metre-long Nikon TTL Remote Cord SC-28/SC-29, while Canon has the 60cm Off-Camera Shoe Cord 2.
Some cameras require you to buy two adaptors - one for the hotshoe and one for the base of the flashgun - and a cable to connect them.
If you prefer to keep your hands free while you shoot and you don't mind looking more conspicuous, you can buy a flash bracket that connects to your camera's tripod socket and angles the flash unit permanently to one side.
Large hammerhead flash units, used for illuminating larger subjects like buildings, are commonly used in conjunction with a bracket.
Flash photography tips: replicate studio lighting with two off-camera flashguns
Using an on-camera flashgun to illuminate small subjects closer than about 60cm is a really bad idea because the flash output at such close range is way too intense.
The position of the flash head above the lens also causes most of the illumination to pass over the top of the subject. With close-ups further than 60cm away you might just get away with on-camera flash, provided you maximise diffusion using a wide-flash adapter and a diffuser.
Take care that a long lens isn't obstructing the flash and, if possible, set the tilt position so the flashgun is pointing slightly downwards.
This solution is far from an ideal though - you'll get far superior results if you use either diffused off-camera flash to one side (with a reflector on the opposite side to fill in the shadows), a specialist macro ring flash such as the Canon MR-14EX or Nikon SB29s or, as we've done here, a couple of wireless TTL flash units positioned either side of the subject.