How to choose a flash for your digital camera

Picking a flash is pretty complicated these days.  Modern flash units are tiny computers with amazing abilities.  Both the Canon and Nikon flash systems allow flash units to communicate with the camera in real time.  Using wireless signals, all of the flash units fire a "pre-flash" to test the lighting conditions of the scene.  Based on the information gathered in the camera from the pre-flash, they all fire simultaneously with exactly the right amount of light coming from each flash to create a perfect picture.  This all happens in the less than a second delay between the time when you first press the button on your camera to the time when the camera shutter opens to take a picture.  It's amazing technology!

And despite that fact that most cameras have a built-in flash mount, actually putting the flash on it is usually a terrible idea.  You will quickly discover that getting the flash off the camera and being able to fire it remotely is vital to getting good images.  In the second section of this article, we will give you suggestions on hardware that will allow you to use your flash remotely.

Note: This guide is specific to the Canon and Nikon lighting systems.  Covering every manufacturer would be impossible.  If you use a camera made by a different manufacturer, feel free to post a comment with flash recommendations for your camera!  Also, this article is focused on TTL speedlight flash systems.  It does not attempt to cover the wide range of manual flashes available.

Step 1: Choosing the Flash Unit

"Dumb" flashes

All of the flashes made by Canon and Nikon support TTL or "through the lens" metering.  This is the ability for the flash units to send out a pre-flash, have it analyzed by the camera "through the lens" and then have the camera tell each flash how much light to put out for a proper exposure.  This ability makes it much easier to capture great pictures on the go, but it also makes the flash units more costly.

If you are working in a studio where the power of each light can be dialed in carefully (or if you fancy yourself a master of manual exposure control), you may not need the ability to do TTL.  However, TTL flashes can still operate perfectly fine in manual mode so the only reason not to get TTL flashes is to save money.  But think carefully about your future needs before skimping up front.  TTL is very powerful and you may find yourself wishing you had the ability later on.

Cheap-o Flashes

If you can't afford anything better but still want TTL support, you can grab one of these flashes.  They are not particularly powerful and they don't play very well with other brand-name flashes, but they are cheap. If there is any way you can afford it, get something better instead (or live with a dumb flash).  It will be a much better investment in the long run.

Small Flashes

These don't put out a whole lot of light, but they are better than anything that might be built into your camera.  These flashes are ideal if you have a small camera or mid-sized cameraand want a small flash to go with it.  For any other use, plan on getting something bigger.

Mid-range Flashes

These are great all-around flashes are will fill the needs of most non-pro photographers.  However, most of these can only operate as a "slave" flash and can't command other flashes.

High-end Flashes

These are the top flashes available without buying specialized studio lighting equipment.  These flashes have full support for acting as both a master and a slave when talking to other compatible flashes.  If you have the money and plan to use multiple flashes together, you probably want at least one of these to act as a master flash. They also put out more light than smaller flashes.

Step 2: Getting the flash off of the camera

Now that you have acquired one or more flashes, you need to figure out how to get them off the camera.  Flash units mounted on the camera shoot light directly at the subject.  This makes for very poor lighting.  You can get amazing results by placing the flash or flashes at an angle to the subject instead of pointing it dead on.

There are many ways to trigger a flash remotely, both wireless and using wires.  Each has advantages and disadvantages.

Camera-controlled infrared wireless

Both Nikon and Canon flashes can be triggered using signals from a camera.  However, only certain camera bodies support this feature.

Pros:

  • Full TTL automatic exposure for each remote flash unit

  • Doesn't require anything besides the camera and flash unit

Cons:

  • Requires "line of sight" between camera and flash

  • Only works over a limited distance

  • Doesn't work well outside in bright light

  • Only supported on a few camera models

    • Canon: 7D

    • Nikon: Most newer models with a pop-up flash built-in

What to buy:

  • Nothing.  If you have the right camera and flash unit, you can try this out now!

Infrared wireless with camera-mounted commander

If your camera doesn't have the ability to act as a flash commander (or master in Canon terminology), you can buy an add-on module to act as a flash commander.

Pros:

  • Full TTL automatic exposure for each remote flash unit

Cons:

  • Requires "line of sight" between camera and flash

  • Only works over a limited distance

  • Doesn't work well outside in bright light

  • Requires an expensive add-on module

What to buy:

Canon

Nikon

Infrared wireless using a flash unit as a commander

If your camera doesn't have the ability to act as a flash commander (or master in Canon terminology), you can use higher-end flash units to trigger other flashes.

Pros:

  • Full TTL automatic exposure for each remote flash unit

Cons:

  • Requires "line of sight" between camera and flash

  • Only works over a limited distance

  • Doesn't work well outside in bright light

  • Requires a top-of-the-line flash dedicated to the task of firing other remote flashes

What to buy:

Canon

Nikon

Flash Sync Cord

The low-tech solution to using a remote flash is to use a flash sync cord.  With the right cord, you can retain full TTL capabilities.  However, the cables can be expensive and can get in the way.

Pros:

  • Full TTL automatic exposure for the remote flash unit

  • Low tech and very reliable

  • Everyone should own at least one of these as a back-up

Cons:

  • Limited to just one flash

  • Limited cable length

  • Cables can get in the way

What to buy

Canon

Nikon

Radio-controlled Flash Triggers

For the ultimate in flexibility, you can buy remote trigger systems for flashes that use radio signals to communicate.  This avoids the light of sight limitation, but it doesn't come cheap.  Most professionals go this route.

Pros:

  • Full TTL automatic exposure for each remote flash unit (if you get the latest models)

  • Very reliable (if you get the right brand)

Cons:

  • Expensive

  • Lots to buy - you need a transmitter plus a receiver for each flash unit

What to buy:

Canon

Nikon

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