We have seen them all, portrait shots where the model has big red pupils. Or a face without definition, with dark shadows along the edges. In addition to that, the model sees bright stars right before his/her eyes. When the flash goes off full on the face. Which more often than not, does not show him/her in a flattering light. With a few simple adjustments, and a little theoretical knowledge. You can achieve a much more natural, and more satisfactory result. This is the second part of a series that discusses flash units.
Fortunately, it is usually not as bad as described above, since most accessory flashes, and cameras utilize compatible mechanisms. Whereby the flash, often, does not fire at full power when it’s not necessary. Both Nikon, and Canon have their own proprietary programs that help you get the correct exposure with the flash. At Canon the system is called E-TTL, while Nikon calls it iTTL. TTL stands for ‘ through the lens ‘, whereby the camera calculates the amount of light needed. The flash then, will apply the correct exposure strength. This kind of mechanism is also available in flash units.
However, that does not mean that when you have a flash, you’ll just focus it in front. And the camera will magically resolve all issues in your scene. The flash itself provides light over a relatively small area, much smaller than the subject. As a result, the quality of the light it produces is referred to as ‘hard lighting’. Because the light comes from the front of the subject, the image it creates is not as clear. And lacks the subtle shadows needed to accentuate the model’s face shape, and texture.
It is therefore very important to find a way to soften the light. We do this by increasing the surface on which the light is distributed. The shapes, and contours of the face are shown more clearly, when the light comes at an angle.
Softer light by reflection
The beauty of accessory flash units, is that the flash can be rotated in all directions. This allows you to have control over the direction of light, which lets you illuminate your model at an angle. To achieve this, you can use any available surface in your surroundings. For example, you can direct the flash head to the ceiling, a side wall, or even a white T-shirt. So the light will bounce off of them, instead of firing it directly on your subject’s face.
As long as the light is distributed over a relatively large area, before it bounces back to your model. The resulting light is softer, and because the light comes from an angle. The shape of the face becomes more defined, beautifully accented with light and dark parts. With this technique, you will notice that the quality of the images created, are far more superior.
If you use a ceiling flash (place the flash in a 45 degree angle. So that the light will reflect on your model or subject. Also at an angle), you can get a reasonably uniform exposure of the subject, and the room. If you stand too close to your subject, then the flash reflecting on your model’s eyes might result to red-eye. To avoid this, you can use a bounce card.
Flash Via Ceiling
If the light coming from the flash is bounced off of the ceiling, in a 45 degree angle. Since it might cause red-eye. Focus the flash on the wall behind you. So it will bounce off to the front, which is very effective in backlit situations.
Flash Behind Camera
If the flash is facing to the rear, and the light is reflected on a big piece of furniture. It may cause some issues on the photo’s white balance. If you shoot in RAW format, this can be easily corrected. By aiming the flash on a side wall, you let the light bounce off of it, then when it reflects on your subject, it produces soft lighting, which accentuates the shape of the face with its soft shadows.
Flash Via Side Wall
Light via a side wall, a few meters from the camera and flash. The distance from the surface where the light should reflect, determines how much flash power is needed. The distance of the model relative to the light source influences how soft the light is. The further away from the reflecting surface, the softer the light will be. Don’t make it too soft, since shadows are very useful for displaying forms and textures.
A white surface is ideal as a reflecting surface, since the light it will throw back will have a neutral color. If the light bounces off a red wall, or a green tablecloth. The reflected light will take on the color of these surfaces, and will cast a reddish or greenish tinge on your subject, which is not what you want. You can make good use of this principle, for example, when using a reflection screen, which is sometimes available in a bright golden color. This creates a warm glow over the subject, and the scene then, attains a warmer tone than it really has.
Another way to soften the light is by using a diffuser, a neutral colored piece of plastic. The light becomes distributed evenly across the room, creating a more pleasant exposure. There are several vendors that also sell complex (expensive) contraptions that spread out light in such a way that you can achieve differentiation, and lovely artistic effects. For example, the Lightsphere by Gary Fong, or the Beauty Dish. But sometimes, attaching a simple salad dish to your flash can produce an equally beautiful effect, without having to spend a lot.
Achieve Soft Lighting
Reflecting light is a good way to achieve soft lighting, with the creative use of your flash. But don’t think that soft light is always better. It depends on the situation, and your artistic vision. Sometimes, hard, direct, light is better to accentuate parts of your subject, or to give the image a certain ‘ edgy ‘ look. And not to mention the various uses of flashes of one’s camera, which merits a whole article for discussion, altogether.
How do you know if you have the correct exposure, and have not overexposed? For this, you can use the histogram on your camera. It allows you to instantly see if there are parts of the photo outside the dynamic range of the camera. On the left are the dark tones, on the right side are the light tones. The chart indicates which portion of the photo shows the most range. If the chart is very high all the way to the right, then there may be details in the light areas that might disappear, so you’ll need to adjust exposure. The same is true on the left, for the parts in shadow.
Another useful tool is the ‘ Blinkies ‘ on the camera. This blinking indicator shows what part of the photo is possibly over-exposed. If you see this in someone’s face, then it is a good idea to adjust the strength of the flash, since too bright parts in the face, decrease the overall quality of the picture, and you lose shadow and detail in those parts.
The camera-flash with TTL works generally pretty well, but just as with the camera without flash on auto-mode, you can override this function if you want. Just like the camera, it also has the possibility of a flash compensation of -2 stops, to + 2 stops. Sometimes, you may want to use flash only when you want to lighten shadows –or use fill-flash, where less power is used, and, imagine for example an underexposure in 1 stop (-1 EV). When shooting large white objects, such as a wedding dress, it is sometimes necessary to overexpose, because the white will otherwise appear more gray (18% gray, where the camera focuses). By playing with the flash compensation, you can adjust the effect of the flash. Read more about what your flash can do by checking the equipment manual..
If you work with a flash, you’re going to work with two (almost) separate exposures. Your foreground is lit by the flash, then the background exposure is, to some extent, completely determined by the shutter speed of the camera (for the chosen aperture, and ISO). The shutter speed does not affect the strength of the flash, the exposure of your subject, only depends on the amount of ambient light hitting the sensor. With TTL, the camera determines the right amount of flash needed for the subject to be as properly exposed as possible.
The amount of light from the flash, with the correct shutter speed, determine how your background will look like. Ambient light, makes the picture look less like a flash photo, and you can get a clearer image of the scene’s atmosphere, or the environment. A well executed photo, with the right balance between flash, and ambient light looks so much better. Manipulating the background light is, in English-language articles, often referred to as “dragging the shutter.” I have not yet encountered a good Dutch term that accurately describes this, but what it comes down to, is that you adjust the shutter speed, to allow more light to hit the sensor, thereby changing the scene’s atmosphere.
Change The Shutter Speed
Only change the shutter speed of 1/160s to 1/60s to 1/25s, the exposure of the subject remains practically the same.
This works best in a backlight situation. If you want to change the shutter speed, ISO, and aperture, to set the exposure, use the manual mode of the camera. This way, you will have full control over shutter speed, aperture, and ISO. If you are using the P mode or aperture preferences, then you lose control over the shutter speed. With the compensation on the camera (not the flash compensation), you can bring the shutter speed to a value that you want, but that value can be set, so you return to the previous settings, at each change of your framing change.
If you like an (almost) black background, then adjust the shutter speed to very fast, if you want to make use of the room’s ambient lighting, then set the shutter speed too slow. If you want to have the background not to have perfect highlights, but you want a greater contrast between the foreground, and background, then you can set the shutter speed on the background, 1 or 2 stops underexposed. Or you’re just looking for a ‘ high-key ‘ effect, with a completely white background, then you can overexpose it. To achieve this effect in a dark room, set the shutter speed too slow, so more ambient light can reach the sensor.
Make sure that there are 1.5-2 stops difference between the foreground and background. So your subject can be clearly seen against the background. For the proper exposure of the subject, make sure there is enough light, and adjust the shutter speed as needed. The background-foreground contrast ratio changes, of course. Please note that the light coming from the flash, somehow ‘ leaks ‘ or ‘spreads’ to the background. So it can light up the background if your subject is nearer the background than the flash. For the light to properly cover the distance, adjusting the shutter speed determines the kind of exposure you will have.
If the ambient light is limited, for example, during a sunset, and you want to highlight the environment in some way, (say 1 stop less than the subject) then set the shutter speed too slow so that your model won’t have to stand still for a long time while you take the shot. Since changing the shutter speed, and the background light determines the sharpness of the picture, you also need to adjust your ISO, or aperture settings to compensate and get the best exposure for your photos.
Using 1/15s to 1/30 s is a 1 stop adjustment, then your ISO setting should be 100 to 200, or your aperture from f/8 to f/6.5, in order to achieve the same backlight, and still get a faster shutter speed to prevent blurring.Naturally, an aperture adjustment has consequences on your depth of field, while changing the ISO has an impact on the amount of noise. And don’t forget the amount of light that your flash calculates to use in the scene, if you are not using the functionality of the camera TTL-Flash combination.
As with many things in photography, everything is connected to everything else, and the effect that you get is a compromise, a sum of all your efforts. But because of this, it is also, perfectly possible to have an infinite array of creative choices, and really influence the end result. Realizing your vision is so much more satisfying, than simply pressing the shutter button while your camera is on Auto-mode.
A useful tip to make sure your model is not going to move during extended exposure at a slow shutter speed, is to make use of the rear-curtain sync function of your camera. This makes the flash fire, not at the beginning of the exposure, but just before the shutter closes. This lessens the chance of your model moving to strike a new pose when she thinks you’re done taking the shot.
It is also important to tell your model that the shutter speed will be relatively slow, that exposure will take longer than usual, and that they therefore must remain still, so the image will not be blurred.
The principle of using different shutter speeds for the foreground, and background is also a great method to apply when capturing images in motion. For example, during sport events, I often choose a longer shutter speed to be able to make the background appear out of focus. The subject then is sharply in focus, but the background is shown, blurred , or out of focus. To help make your subject appear sharp on your photo, you can use a flash. This ensures that there is enough light on the subject, and shows all the important details.
However, if you do this with longer shutter speeds, there will be a kind of ‘ ghosting ‘ effect, wherein parts of your subject may appear to trail behind the original image. In pictures with movement, this, indeed looks strange, because the movement may be in a certain direction, but this ghosting effect goes in the opposite direction. By using the rear-curtain sync, you still get the ambient light, and capture the movement, but just before the shutter closes, another flash fires so it will properly provide light to the subject that is still on the move.
Explanations on the use of flash units often include all sorts of calculations and physics, making it unnecessarily complicated, causing many people to zone out, or discontinue their lessons. If you used the above principles as a guide, in conjunction with the TTL functionality of your camera-flash combination, they form a good foundation for better, and more creative photos using flash, minus the disadvantages commonly associated with flash photography. There is still plenty to say about exposure with a flash, for example, what do you do if your flash runs out of battery? This will be covered in a future article. Another topic for future discussion is about the capabilities of the camera with the flash turned off. For now, have fun playing with that flash!