Get started with flash photography: Understanding the basics

Get started with flash photography: Understanding the basics

It can be daunting to get started with flash photography. I bought a very cheap flash when I was starting out and it went so poorly that I resisted delving into flash for years after. This is far too confusing, I thought. I’ve no idea what I’m doing — and what I’m doing wrong!

It wasn’t until I booked my first full day wedding shoot that I forced myself to bust through the barrier. I wish I’d done it sooner. Flash photography really isn’t as hard as it seemed (I promise!). Once I understood a few basic principles, I was able to build on them to create a lot of cool effects like this simulated golden hour and this night portrait.

What gear do you need to get started with flash photography?

There are three basic ways that you can use a flash in your photography:

  1. A single on-camera flash.
  2. An on-camera flash and one or more off-camera flashes.
  3. One or more off-camera flashes.

I personally shoot wedding receptions with configuration 1 (occasionally 2 or 3, but much more often 1). I use the same for indoor shoots (for branding, families, newborn, etc). For outdoor creative stuff at night I use configuration 3.

This photo was created with two off-camera flashes (one on either side of the couple, hiding behind trees), a yellow gel over the left hand flash, and photography smoke in a can.

At a bare minimum you need a single flash that you can mount onto your DSLR. Add to that transmitters and receivers to get it off-camera, and you’re good to go. Down the track you can add umbrellas, softboxes, lightstands and more (the fun never ends) but it’s not necessary to take great photos. Popping the flash on a table and bouncing it off a wall it enough for a great photo!

If you shoot Canon, this is what I’d buy to get started. There’s a similar collection for every major brand out there (and third-party options like Godox too). For a full list of the flash gear I use, check out this post on my blog.

Understanding how flash photography works

Now that you’ve got at least one flash (right?!) let’s talk basics. When getting started with flash photography, think of it as taking two photos in one. Get the background how you like it with the camera settings, and the subject exposed with flash settings.

getting starting with flash photography
The exposure triangle becomes two triangles when you add a flash to your setup.

You set your camera to expose for ambient light with your camera exposure triangle (i.e. ISO, aperture and shutter speed). For subject light expose with your flash exposure triangle (ISO, aperture and flash power). ISO and Aperture affect both exposures, shutter speed affects the ambient exposure, and flash power affects the subject exposure.

For example, the basic settings I use for evening events (like a wedding reception) are ISO 800, 1/40s or 1/60s, f/2.8, with flash on ETTL with Rear Curtain Sync (see more on this below). The slow shutter and ISO 800 captures the ambient light of the room. The flash burst freezes subjects (meaning that there is no blur).

get started with flash photography
The background light is balanced with the ISO, shutter speed and aperture, and the subject is exposed with the flash power, ISO and aperture.

Controlling the flash power: Getting started with flash photography modes

How then do we control the flash power to get different effects? Flashes work in different modes. The two main modes are Manual, where you tell the flash how much to output as a fraction of it’s max power, and ETTL: Evaluative Through The Lens metering.

Evaluative Through The Lens flash metering

In ETTL the flash sends out a test burst to judge how much flash is needed to expose the scene properly, then actually takes the photo. The flash power is set automatically. You won’t notice the test flash unless you are using Rear Curtain Sync and a long exposure time (e.g. ½ s or longer). However, sometimes your subjects will! It’s why people tend to blink in flash photography. Their brain registers the test flash a fraction of a second before the shutter opens and captures the photo.

get started flash photography
I used ETTL on both flashes for this photo: when there are two flash bursts in the scene, the pre-fired test flash senses this and adjusts each flash accordingly.

I personally find ETTL perfect for almost every situation, except for light painting. This is because I don’t want the subject exposed “properly,” in this case. I might want them underexposed, or want the flash firing to create a starburst. You can adjust the ETTL output relative to the “proper” exposure by using flash exposure compensation. If your subject is coming out overexposed, then turn the flash exposure compensation down 1/3 stop, 2/3 stop, etc.

Flash compensation to adjust flash power

Flash exposure compensation can be done in camera through the settings menu. Generally DLSR will have a button assigned to it on the body. You’ll also find it on the back of the flash if mounted, or on your transmitter if using it off-camera.

get started with flash photography
If you find your flash is putting out too much light and ruining the ambience, you can compensate with the flash exposure compensation settings.

Manual flash can be set with a light meter or by eye (literally by taking test shots and adjusting). Use manual when you don’t want the flash output changing from shot to shot (ETTL will evaluate every shot and set the power accordingly).

Getting started with flash photography sync modes

Now you know how to control the power of your flash, the last thing to think about when getting started with flash photography is choosing the right sync mode.

There are three sync modes for your flash: Front Curtain Sync (the default mode), Rear Curtain Sync and High Speed Sync. Front Curtain Sync fires the flash on the “front curtain” (i.e. when the shutter opens). Rear Curtain Sync fires is on the (you guessed it) “rear curtain,” or just before the shutter closes. Let’s look at High Speed Sync first.

Understanding High Speed Sync

For using flash with high shutter speeds (usually above 1/250s; or whatever the “native” sync of your camera is), you need to turn on High Speed Sync. If you have a flash on your camera and find your shutter speed won’t increase past 1/250s, it’s because your flash isn’t switched on to use High Speed Sync.

flash photography high speed sync
This photo was taken in my very bright kitchen, with morning light streaming in around my subject. Turning the flash to High Speed Sync and making the shutter speed super fast makes it possible to still capture a low-key image in these conditions.

High Speed Sync is useful during the day when you want to use flash as a fill while also having a wide aperture for the background. It’s also good for freezing fast moving things like sports players, animals and vehicles. You can also use it to create a low-key look in bright light, as above.

Understanding Rear and Front Curtain Sync in flash photography

For slow shutter speeds (i.e. dark event settings, night photography): put your flash on Rear Curtain Sync. The camera gathers ambient light then “stamps” the subject onto the background (illuminated by the flash) right before the shutter closes.

rear curtain sync flash photography
The subjects are stamped onto the background at the end of the exposure with Rear Curtain Sync.

If you try to take the same photo with the flash set to Front Curtain Sync, you will get ambient light glow over the top of your flash-illuminated subject (not what you want). Generally, the default setting for a flash is Front Curtain Sync. Personally, I always have Rear Curtain Sync turned on. It works better for slow shutter speeds, and makes no difference for fast shutter speeds.

rear curtain sync flash
The Rear Curtain Sync in this flash photo freezes the action of the subjects, while the camera exposes for the background ambient light.

Honestly, I don’t know of a situation where Front Curtain Sync is preferable to Rear Curtain Sync. Can having your flash on Rear Curtain Sync ruin the photo? I don’t think so. The only exception is when you need High Speed Sync (on my flashes at least, it’s either Rear Curtain or High Speed and I can’t select both as once). I’d love to be proven wrong: Let me know in the comments a situation where Rear Curtain Sync would not work!

front curtain sync flash photography
The ambient light is blurring over my subjects in this Front Curtain Sync flash photo.

How to change the sync settings of your flash

Look at your flash manual and/or your trigger system manual to find where to enable these settings. It could be in any one of:

1. The camera’s settings

2. The flash’s settings

3. The trigger’s settings

Check your manual and what you’re mixing-and-matching.

Getting started in flash photography is easy once you get the basics

Don’t be like me and shy away from flash photography. It’s a fun avenue to expand your photography skills and to create beautiful effects. Just remember the basis: expose for the subject with your flash, and expose for the ambient light with your camera.