Flashgun – What To Look For When Purchasing

A flashgun is essential in order to improve your flash photography. Most digital SLRs come with a built in flash. While there are occasions when this can be used, you can dramatically improve your flash photography by purchasing one. There are a number of reasons:

  1. They have insufficient power to light anything but very close subjects. This makes it impractical for most wildlife photography, especially bird photography.
  2. They make your images look flat and two dimensional because the flash is immediately next to the lens, producing dense black shadows directly behind the subject.
  3. They often cause red-eye or their wildlife equivalent of green-eye, white-eye, yellow-eye and other variations.

When you make your purchase there are a number of things that you should consider as a minimum.

Through The Lens (TTL)

A flashgun and camera body with TTL capability is a godsend. This allows the light coming through the lens to be measured and the flash output set accordingly. As soon as the camera has recorded sufficient light for the correct exposure the flash will be automatically switched off.

Without TTL it is necessary to manually calculate the aperture required at the camera to subject distance. The aperture is then fixed otherwise an incorrect exposure would be recorded.

High Guide Number (GN)

Try to purchase the most powerful flashgun you can because its range will be greater and you’ll be able to shoot subjects that are further away. While the range can be extended by using a flash extender, it is still better to buy a powerful one in the first place. A flash extender will then extend its range even further.

The power is measured by the Guide Number. Guide Numbers are different at different ISOs and can be quoted in meters or feet, so be careful when comparing guide numbers and make sure you’re comparing like with like.

For Example

Canon Speedlite 430EX II GN = 43 meters / 141 feet, ISO 100 at 105mm

Canon Speedlite 580 EX II GN = 58 meters / 190 feet, ISO 100 at 105mm

Nikon Speedlight SB-900 GN = 34 meters / 111 feet, ISO 100 at 35mm

Nikon Speedlight SB-900 GN = 38 meters / 125 feet, ISO 100 at 35mm

Horizontal and Vertical Swivel

Choose a flashgun that can swivel horizontally (Swivel Head) and vertically (Bounce Head). This allows you to use bounce flash. Although there aren’t often things that you can bounce the flash off with wildlife photography its useful to be able to when there are.

Short Recycle Time

The recycle time is the time it takes the flash-gun to be ready for the next shot after it’s just been fired. This is particularly important for wildlife photography because you’re often taking quite a few shots when the subject appears or starts showing the behaviour you’ve been waiting for.

Second Curtain Sync

If you like to take creative shots that show motion blur then make sure the flash gun you purchase has a second curtain sync option. This ensures that the motion blur appears behind the subject. First curtain sync (the default) will record the motion blur in front of the subject.

Work at any Shutter Speed

With conventional flash your camera has a maximum shutter speed that will work with your flashgun. This is known as the maximum flash sync speed and can be anything form 1/60s to 1/250s or even 1/500s. Quite often in wildlife photography this isn’t fast enough.

When using Aperture Priority mode, which is most of the time, you’re trying to shoot with a high shutter speed and a low f/stop. Because the shutter speed can’t go above this maximum speed you may be forced to choose a high f/stop – exactly what you don’t want.

If your camera needs to set a shutter speed higher than its maximum sync speed, it will leave it at its maximum and a warning light will flash in the viewfinder. In the heat of the moment you’ll often miss the warning and finish up with shots that are extremely overexposed. The overexposure is often mis-interpreted as too much fill flash.

The solution to this is:

Make sure that your flashgun can work at any shutter speed. Canon call this “High Speed Sync” and Nikon call it “Auto FP High Speed Sync”.

If you turn this on then you can shoot at whatever shutter speed you want. You can leave it turned on permanently on your Canon or Nikon flashgun, which will use normal flash until the shutter speed is too high, at which point high speed sync will kick in.

Further Reading

Discover the best Canon flashgun and how it will help you dramatically improve your flash photography.

Flash Brackets – A summary of what to look for when purchasing a flash bracket.

Flash Extender – How to extend the range of your flash gun.