The studio was lit bright pink the day we filmed this, because sometimes you need to make a sensible educational video… and sometimes you need to make the studio look like a strawberry milkshake exploded. Why wouldn’t you. Anyway, we get asked this all the time: “What’s a quick and reliable method for setting up off-camera flash?” Not “the perfect method”, not “the method that requires a light meter, a spreadsheet and three engineering degrees”. Just something you can do every time, under pressure, with a subject waiting, that gives you a clean, repeatable result. So here it is.
The simplest off-camera flash setup: background first, flash second
This video isn’t about perfect light positioning (that’s a whole other rabbit hole). It’s about something far more practical: How to set the power of the light quickly.
The core idea
You balance your exposure in two stages:
- Ambient (background) exposure
- Flash (subject) exposure
If you do it in that order, you stay in control. If you do it the other way round, you end up chasing your tail while your client slowly forgets what their face feels like.
Step 1: Turn your trigger OFF (no flash)
First job: make sure the strobes aren’t firing at all. Trigger off. Silent lights. Peaceful studio. Now take test shots until the background looks exactly how you want it. That’s your ambient exposure. Nice and simple. In the video, I’m working at:
- ISO 200
- 1/180 sec
- f/2.8
At this point, I’m not thinking about Millie. I’m thinking about the pink. It’s all about the background and how I want it to render. Want the background brighter? Adjust exposure. Want it darker and moodier? Adjust exposure the other way. Just keep an eye on your sync speed, obviously. No need to summon the black band of doom across the frame.
Step 2: Turn your trigger ON (add flash at minimum power)
Once the background looks right, now you bring the flash back into the equation. Turn the trigger on, and take a test shot with the flash power as low as it’ll go. Why start low? Because it’s predictable. You can always add power. Starting too hot is how you end up with a perfectly exposed forehead and a subject who thinks you’re testing a lightning machine. In the video, the first pop is actually pretty decent, but it needs a little more, so I nudge the power up by a couple of notches and shoot again. That’s it. Tiny adjustment, second frame, done.
Why this works (and why it’s so repeatable)
Because you’ve separated the problem into two clean decisions:
- Ambient exposure controls the background
- Flash power controls the subject
When beginners struggle with flash, it’s usually because they’re trying to fix both at once and it becomes a messy guessing game. This method turns it into a checklist.
Quick troubleshooting (because real life happens)
- Subject too dark: increase flash power a notch or two
- Background too dark/light: adjust ISO/shutter/aperture with trigger off, then switch it back on
- Want shallower depth of field (wider aperture): you’ll likely need to lower flash power, or move the light back
- Want darker background: increase shutter speed (staying under sync) or lower ISO
And yes, you can absolutely refine from there, but this gets you to “good” fast, which is the whole point.
The result
A beautifully balanced portrait, a bold pink background, and Millie looking like she’s never been asked to “eyes to meet” in her life. Perfect. If you want more full-length videos that walk through lighting setups properly, step-by-step, with the reasoning behind each choice (and not just the final pretty picture), join the Mastering Portrait Photography membership and work through them with me. Go and try this method on your next shoot, even if the background isn’t pink. Though… I mean… it could be.