Built-in Flash Techniques #4: How to Shoot Portraits Against the Sunset
Sunsets make beautiful backdrops for portraits, but they also mean dim lighting conditions. If you shoot without a flash, your entire shot might look darker than expected. But even if you use a flash, the background might still look too dark although your subject is well-lit. Why is this so and what can you do to fix it? Find out in this article. (Reported by: Teppei Kohno)
FL: 60mm (96mm equivalent)/ Manual exposure (f/5, 1 sec)/ ISO 100/ WB: Auto
Flash exposure compensation: EV-0.7
Retaining the brilliant sunset colours while ensuring that the subject is well-lit can be trickier than it seems.
I used the flash, but why did my background turn black?
In previous articles, we learnt that firing a flash in backlight can reduce the shadows on your subject. Being the good photography student that you are, you decide to try it out while shooting a portrait against a sunset. After all, sunset is also backlight, isn't it?
But when you review the shot, you get a shock. Your subject is well-lit, but the lovely sunset colours have been reduced to black. What happened?
Assuming that you are already using a relatively wide aperture, your shutter speed is probably too fast. The flash helped to light up your subject, but since itcannot reach the background, the background is underexposed and appears black.
The solution is simple: Fire your flash while using a slow shutter speed. This is also known as slow sync technique.
Tip: Using a slow shutter speed makes the shot more prone to blurring from camera shake. For best results, place the camera on a stand or use a tripod.
Shot at 1/60 sec: Background is black
FL: 27mm (43mm equivalent)/ Program AE (f/4, 1/60 sec)/ ISO 200/ WB: Auto
This was shot with the built-in flash using Program AE mode. At 1/60 second, the shutter speed was too fast, so only the model was captured while the sunset was lost.
Shot at 1 sec: Captures the background
FL: 27mm (43mm equivalent)/ Manual exposure (f/4, 1 sec)/ ISO 200/ WB: Auto
Using Manual exposure mode, I set a slower shutter speed but kept all of the other settings the same as the previous shot. Both the model and the sunset were captured beautifully.
Step-by-step: How to find the best exposure for slow sync flash
A: Find the best exposure settings for the sunset.
B: Pose the model and compose the shot.
C: Take a shot with the built-in flash on.
More details about each step are given below.
A: Find the best exposure settings for the sunset
I did this in two steps.
Step 1: Use Aperture-priority AE mode to take some test shots. Note down the aperture and shutter speed settings that give the ideal results.
Step 2: Switch to Manual exposure mode. Select the settings obtained in Step 1.
B: Pose the model and compose the shot
Make sure you set your focus on your model! It is especially important that the eyes are sharply captured.
C: Take a shot with the built-in flash on.
Check the results. If necessary, adjust the flash exposure compensation.
This technique can also be used for portraits shot against nightscapes:
Brightening Both the Subject and Nightscape Background
You may also be interested in: 5 Portrait Photography Techniques to Take You from Day to Night
Level-up technique: Create a sense of motion—get your model to move during the shoot
When using a slow shutter speed, any movement that occurs while the shutter is open will be blurred in the photo. This is called "motion blur", and you can use it to add a sense of dynamism to your shot.
FL: 35mm (56mm equivalent)/ Manual exposure (f/4.5, 1 sec)/ ISO 800/ WB: Auto
In this shot, I asked the model to keep her face still while swaying her body from side to side. The 1-second exposure was enough to create a sense of motion in the shot, especially in her hair and clothing. It works well with the rich colours of the evening sky.
Want more creative possibilities? Use a Speedlite
Sometimes, the composition just happens to look better if you shoot from further away. Or you might want to get creative with your composition by placing your model in different parts of the frame, such as in the corner. It is in scenarios like this where the limitations of your built-in flash become apparent.
This is when a Speedlite comes in useful: Besides the fact that they are more powerful, you can change the angle of the flash head to ensure that subjects placed in the corners of the image are also well-lit.
See how slow sync technique and two off-camera flashes helped to create this beautiful portrait at night in the rain:
How to Capture Raindrops to Create Surreal-looking Portraits
For more about Speedlites, see:
What are the Benefits of an External Flash?
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Born in Tokyo in 1976, Kohno graduated with a Social Work degree from the Department of Sociology of Meiji Gakuin University, and apprenticed with photographer Masato Terauchi. He contributed to the first issue of photography magazine PHaT PHOTO and became an independent photographer after that, in 2003. The author of many books, Kohno not only shoots all sorts of commercial photographs, but also writes prolifically for camera and other magazines.