For beginners and those new to the world of digital photography taking photographs using a flashgun, such as a Canon Speedlite or Nikon SB, can be intimidating. However, there is one fundamental thing that should be remembered and that is that flash photography basically involves making two separate exposures at the same time and combining them in to one image. Once you get around this basic concept you will find flash photography that much easier and your flash photographs improve accordingly.
An external flashgun, such as this Canon 430EX11 can really help take your flash photographs to the next level. Combine this with some Cactus V5 radio triggers and you can take your flashgun off camera for even better results.
Whilst your flashgun may be powerful enough to adequately light a person or a small object, it is not powerful enough to fully illuminate a football field which is pretty obvious. So, considering this when taking photographs using flash it soon becomes clear that the flashgun will only light up your subject. Illuminating the subject is the flash exposure of the combined image, i.e. exposure number one. The second exposure of the final image involves photographing the background, i.e. the parts the flashgun cannot light, and this is known as ambient exposure. So, with two separate exposures to make the million dollar question is “how do we go about making the two exposures?”.
The first step is to meter the background and expose for that. Metering the background can be done with a specially dedicated light meter or the camera’s internal light meter, the decision is entirely up to the individual photographer. Let’s say we are using the camera’s internal light meter, so with the flash turned off we need to set the desired aperture, point the camera at the background and press the shutter button halfway and take a meter reading to obtain the shutter speed required to correctly expose the background.
Once we have the meter reading we now have a decision to make. We can either follow the suggested settings or we can tweak them depending on what we are trying to achieve. The ultimate decision will depend on the desired effect and the mood of the shot. We may want to create mood or atmosphere and deliberately darken the background by underexposing it by a stop or two. This is achieved by closing the aperture or decreasing the shutter speed. Alternatively, we may want to lighten the background by a stop or two and intentionally overexpose it by widening the aperture or increasing the shutter speed. The decision is entirely up to the individual, however we do need to remember the fastest shutter speed possible is the camera’s flash sync speed, which is likely to be 1/250 at the very fastest. It is crucial we work within the camera’s parameters at all times, so this maximum shutter speed needs to be borne in mind.
Once we have decided on the mood of the shot and how we want to expose the background the next step is to set the flash exposure to correctly light up the subject. Flash exposure is dependent on a combination of the aperture, the flash to subject distance and the power of the flash. Shutter speed does not affect flash exposure. So, with the camera in manual mode we need to dial in the shutter speed (being the camera’s fastest sync speed or slower) and the aperture required to get the exposure we are after.
The easiest way to set the flash is to use a flash meter, if we have one. If we do not have a flash meter then it is likely to take a bit of trial and error to set the correct flash exposure.
A good starting point is to set the flash at 1/8 power and take a test shot. Once the test shot is taken look at the histogram on the LCD on the back of the camera to see what the exposure is like. If it is too dark we need to increase the power. If it is very dark increase the power to a ½ power, if it is only a bit dark increase the power to a ¼ power. If the exposure is too light we need to decrease the power. If it is very bright decrease the power to 1/32, if it is only a bit light decrease the power to 1/16. With the adjustment made take another test shot and check the exposure once more. It is important to keep changing the settings and taking test shots until the exposure is how we want it. When making these adjustments it is important to rely on the histogram and not the LCD screen since the histogram is far more accurate.
When first starting out in flash photography setting the flash exposure will take time, however as photographers become more experienced the time will decrease significantly and the adjustments required will get less and less. The key is to practice, practice, practice and then practice some more. Persevere and you will get there.
The above describes the basic method to take photographs using a flashgun and by approaching every flash exposure you make with method described above you should find your flash photography will improve. Just remember, expose for the background and ambient light using a combination of the aperture and shutter speed and expose for the subject by altering the power of the flashgun and moving closer to, or further away from the subject as necessary.