I came up with the idea for this Tuesday Photo Tip while talking to a colleague on the East Coast. He was snowed in. I jokingly promised to send him a photo so I snapped this shot of our bedroom with the French doors wide open illustrating “another day in paradise” weather.
The reason for showing this is to illustrate today’s topic. We will give you a simple three step process that will allow you to fully utilize your flash. Three easy steps. Follow along for details…or jump to the end for a list of the steps.
For this “day in paradise” photo I knew I would need flash to balance the outside and inside exposures. That’s done by using your flash and shooting in manual mode. Don’t panic – we’ll list the simple steps you should take.
Here are a few pictures of our backyard at the time I took the bedroom picture. It was a partly cloudy day with big fluffy white clouds. If I exposed for this outside scene the bedroom would be deep in shadow. So let’s add some light to the bedroom to balance the two exposures.
Why are there two exposures you ask? Great question. The answer (below) will eliminate the mystery of flash photography. Once you understand the two exposures you will master flash photography.
Let’s talk about the first exposure. Exposure #1 is the foreground/bedroom which is lit predominantly by the flash on my camera. The flash exposure (exposure #1) is controlled by the aperture YOU choose and the flash power YOUR CAMERA chooses.
You pick the aperture – let’s say f/4 – and the camera will determine the amount of power the flash should produce. Looking at the aperture illustration above you can see that it would be difficult for the flash to pump enough light through a tiny aperture (say f/16).
Here are the first two steps. Step #1: set your camera to manual mode. Step #2: set your aperture to f/4 (read this post to learn why manual mode should be used for flash photography). The next step is handled by your camera – it will automatically choose the flash power needed to properly expose the foreground/bedroom. Exposure #1 is set – f/4 with the camera determining flash power output.
Simple, let’s move on to Exposure #2 – the background – which in this case is our backyard. The flash exposure won’t affect the background – it’s just too far for the flash to have any impact. Here’s a better example of that point.
I used foreground/background exposure balancing for this photo of Rebecca and Doug at Hoag Hospital. In this photo the background is Newport Harbor. Obviously the flash can’t add any light to that.
So let’s dial in Exposure #2, the background. Exposure #2 is determined by the aperture and the shutter speed. That’s no surprise. It is what you are used to considering when you shoot with no flash. But notice – we now have another knob to turn: shutter speed.
For this exercise we’ve already chosen the aperture (f/4) for the flash/foreground exposure. That’s also used in the background exposure. We now are left with a shutter speed decision – nothing more.
We’re looking for a shutter speed that will correctly expose the backyard/background. We find that by doing Step #3 – roll the shutter speed dial until your camera tells you the exposure is correct. You can adjust it to your taste. Often times we will underexpose the background just a bit to get those deep colorful skies as shown in the photo below. The couple is lit by off-camera flash – the background is underexposed by 1 stop.
Maybe you want a high key portrait as shown below. In that case you would choose a slower/longer shutter to let more background light in.
Changing the shutter speed to add flavor to the background exposure will not affect the flash/foreground exposure (determined solely by aperture and flash power).
Find that hard to believe? Try this simple exercise. Take a photo of any object (vase, fireplace, …) in your home with the room lights dim and blinds/drapes closed. Now change only the shutter speed and take that same photo. Check it out – no difference in the exposure because flash exposure is independent of shutter speed. We talked a bit more on that in this earlier post and used the example photos below.
So, to recap, pick a scene that includes a window on a bright sunny day. Then choose an aperture of f/4 and take the photo with different shutter speeds. Start at 1/200 sec, then use 1/100 sec, then 1/60 sec. Be sure you’re at a low ISO otherwise the background will be blown out at 1/200 sec.
See what’s happening? The flash exposure is constant and the background exposure gets brighter as you change (reduce) shutter speed.
That’s the key to flash photography. Really, it’s that simple. Shoot in manual, choose a reasonable aperture (no higher than ~f/8) and dial in the background exposure with the shutter speed. Then flavor to your taste (higher shutter speeds for colorful skies, lower shutter speeds for high key backgrounds). Want that in easy to see steps:
Step #1: set your camera to manual (Try it, you’ll like it – we promise. Your camera will automatically determine the appropriate flash power).
Step #2: Pick an aperture – anywhere between f/2.8 and f/8 will work for most situations.
Step #3: Dial the shutter speed to taste (stay somewhere between 1/15th and 1/200th). Long shutters (e.g. 1/15th) brighten the background, short shutters (e.g. 1/200th) darken the background.
Feel free to comment or show off some of your own compositions that illustrate this tip. In the meantime, stay tuned because more Tuesday Photo Tips are right around the corner. Better yet – be updated automatically when we post Photo Excursions, Road Trips, Family Happenings or Photo Tips by “friending” our Facebook site. We also post favorite photos, along with an explanation of how it was captured, on our Pinterest page – follow us there and join in the fun.
PS - This is one of dozens of photo tips in our continuing Tuesday Photo Tips series of posts. There are other resource articles on our site you may enjoy covering basic and more advanced photography topics. There are also tips that cover topics such as preparing for family or infant/child portrait sessions. If you would like a topic covered just jot it down in a comment or send us a note. Also, if you think your friends or family members would enjoy these tips please pass them on by using any of the share buttons below.