Working with outdoor flash can be difficult, especially if you’re trying to keep it looking natural. The first thing I decide is what direction of light will blend naturally with what my eye sees in the scene.
What I didn’t mention in my last post is that the direction you choose will also impact where the shadows fall. If the shadows look wrong, then you won’t get a natural look.
See Paul’s final image in part 1 of Natural Outdoor Flash Photography >
My best advice is to point the light in a way that makes the shadows fall outside of the frame. That way they don’t even show up in the image. That isn’t always possible, but it’s the easiest way of dealing with them.
Natural Outdoor Flash Part 2
Once you have the direction of your light set, you can start thinking about light intensity, the hardness of the light, colour temperature and modifier shape. This post is about the light intensity and hardness of outdoor flash.
Light Intensity & Balance
There are 3 main ways of changing the light intensity of your flash:
- Change the Power
- Change the Distance
- Change the Angle (feathering)
The balance between your outdoor flash intensity with the ambient light present in the scene will play a big role in “selling” the natural look. This balance is achieved through your exposure settings (aperture, shutter speed and ISO) and your light intensity.
Setting your ambient exposure
In general, if your flash is your key light then you’ll need to make your ambient exposure darker than what you want the final product to be. That’s because the flash will be adding light to what is already in the scene (flash exposure).
If the ambient exposure and flash intensity are too different, then it will be obvious that an artificial light was used. To get a natural look, you’re going to have to keep the intensity of each source of light similar – probably within 1 stop (or less) of each other.
The process will differ slightly if you decide that the ambient is your key light. In that case, you’re going to want to create the ambient exposure that you want and then add in your flash. In order to be subtle, your flash exposure will likely need to be at a lower light intensity than the ambient key light hitting your subject.
Shutter speed will only impact your ambient exposure and not your flash exposure at your camera’s flash sync shutter speed and slower (usually around 1/200s) because the pulse of the flash occurs much quicker than the shutter closing. Flash sync shutter speeds of most DSLRs can be limiting because you’re forced to be at 1/200s or slower, so you have to use aperture and ISO to get the ambient exposure you want.
Often this means that on bright days you have to use a small aperture to get the light under control even at low ISOs. Not ideal if you want that shallow depth of field look or if you want to avoid motion blur with fast moving subjects. There are ways around this:
- Use an ND filter to darken the scene – but then your autofocus can have issues
- Buy a camera system that has leaf shutters that allow for faster flash sync speeds – but then you’re into 5 figure systems like Hasselblad and Phase One/Mamiya
- Use High-Speed Sync or Hypersync enabled flashes/triggers – but then you do lose some flash power as your shutter speed gets faster
Out of these options, the last one is the only one that’s feasible for the type of fitness work I do since I need fast, accurate autofocus and often work at shutter speeds faster than 1/200s.
Aperture & ISO
Changes you make in Aperture or ISO will impact both ambient and flash exposures and neither is limiting in the way shutter speed is.
Setting your outdoor flash exposure
Once your ambient is set, you can then use the three ways of changing the light intensity of your flash to balance naturally. What that balance looks like is up to you and your artistic eye. I just keep tweaking until things look right.
My best tip to you is that if the difference in flash/ambient exposure is very noticeable on your back screen, it’ll be even more obvious once you download the images onto your computer. Subtlety is the name of the game.
The thing to remember when adding flash to a naturally lit scene is that how bright the flash shows up is relative to the ambient light level. This was my biggest hurdle when I was first testing how to naturally use outdoor flash when I got my Profoto B1 (affiliate link). I saw the B1 as a new way of adding light to outdoor fitness shoots due it’s ability to do High-Speed Sync.
In my mind, I thought that using an HSS flash outdoors would allow me to use a lower ISO and avoid noisy photos. What I learned is that since you need to naturally balance flash with ambient, you’re tied to the ambient exposure of the scene.
If you get the direction and light intensity correct, you’re well on your way to creating outdoor flash photography that looks natural.
Hard or Soft Light
The next property of light to consider is whether it will be a hard or soft light source. Just like with lighting direction, it’s easiest to take your cue from the environment.
Fortunately, you can also blur the lines between the two types of light. You can add a harder light to a soft light environment (like the run shot of Dezeraie above), or you can add soft light to a scene where the ambient light is hard.
It’s easiest to mix things up when you have a restricted background, because otherwise it may look out of place.
That’s it for now. Next time I’ll wrap things up with colour temperature and modifier shape.
Happy to answer any questions you may have!
Thank you for this, it is very interesting! I just went thru your blog and i do appreciate your work here, it helped me!
You’re very welcome Philippe, really great to hear that I was able to help you! Love your cycling photography.