For any aspiring photographer, the decision to buy an external camera flash can mark a significant moment in their progress. No matter how expensive their camera, if the ambition is to take professional-quality pictures, the limitations of the on-board flash will sooner or later be exposed. An external flash offers a great deal more than just a significant increase in the available illumination. The ability to direct how the light reaches the subject is probably the more significant factor in how the device will improve overall quality of the images produced.
The Need for an External Flash
The literal definition of the word photography is drawing with light. Professional flash lighting can transform even rather ordinary photographs into beautiful pieces of art. An external flash can be employed to enhance images in any situation when the camera's own flash light would be triggered. An external flash can also occasionally be used to add special effects to a photograph.
Perhaps the most obvious use for an external flash device is to provide additional illumination when there is not enough natural light. The lighting power of even the cheapest external flash will far exceed the firepower of an on-board device fitted to even the most expensive camera. External camera flashes usually run on four AA batteries, meaning they are able to offer the photographer significantly more light to work with.
When photographing a subject indoors, using only an on-board camera flash can often give disappointing results. This is mainly due to the light from the camera flash being reflected directly back from the subject in a straight line. A single light source in the same plane as the camera itself produces an overly contrasted image lacking in fine detail. An external flash can be directed to bounce the light of the surrounding walls and ceilings, softening the tone and enhancing fine details. A more professional looking image is produced, which is more like how we actually see the world, and is therefore more pleasing to the eye.
Many external flashes offer different special effects modes, which allow movement to be captured. Flashes with a strobe mode can be set to rapidly fire several times while to shutter is open, capturing the subject in a number of different positions. A flash which offers second curtain synchronisation mode can be set to fire as the shutter is just about to close, producing trails that subtly outlining the position from where the subject has just moved.
External Camera Flash Advantages
As well as the ability to provide extra light, external camera flashes contain several other advantages over their onboard counterparts.
Manual Power Setting
External flashes give the photographer a greater degree of control over the image exposure by allowing the automatic power level to be manually overridden. This makes it possible to experiment with different levels of illumination, which can greatly alter the mood and feeling of the resulting image. This feature can be particularly useful when the unit is acting as a remotely triggered standalone device.
Reduced Recycling Time
When taking several photographs in succession, camera operation will need to briefly pause to allow the camera flash to regenerate. The length of this pause is known as the recycling time of the device. Camera flashes produce bursts of light which are not capable of being generated in real time by battery power alone. Instead, the batteries are used to charge an internal component, known as a capacitor, until there is enough concentrated energy to trigger the flash again.
External camera flashes use larger battery packs, which mean they can achieve lower recycling times than on-board units. They also have greater battery capacity than the internal camera power source, meaning they are able to produce a greater number of flashes before the batteries need attention. An external flash device may also offer the facility to upgrade the power source to a larger external unit. In doing so, the photographer will gain even better recycling time and battery life advantages over those of the internal unit.
When replacing the internal camera battery, there is a fairly limited choice between the power capacities of the models on offer. However, the same is not true of AA batteries, which are used to power most external camera flashes. A number of battery manufacturers sell products specifically intended for use in high drain apparatus such as camera flash devices. Using these can significantly reduce the recycling time of the flash, as well as providing longer battery life.
Automatic Flash Zoom
Many external camera flashes offer an automatic zoom feature, which focuses the light to where it is most needed. As the camera lens zooms in, the flash narrows its field of light to cover only the area seen through the viewfinder. By concentrating the pool of illumination, the power required by the flash is lower. An external flash with a zoom feature can thus make more efficient use of available power than an internal device.
Auto Focus Assist
A camera determines its distance from the subject by aiming a beam of red light at it and measuring the time it takes for this to be reflected back. It uses this information to calculate which focus setting to use when the camera is in auto focus mode. Most external flashes offer a focus assist facility, which utilises their superior power to send a brighter pattern of light. This enables the camera's automatic focussing system to more easily detect the focus signal. The result is that pictures can be taken more rapidly with the external flash than would otherwise be possible.
Master or Slave Application
For truly professional results, it is sometimes necessary to use more than one additional flash. These extra devices, which are usually referred to as slaves, are wirelessly controlled by a single master flash. Not all external flash devices have the required functionality to be used as a master flash. Those that do tend to be amongst the more expensive models available. Therefore, when deciding which external flash to buy, it is worth considering the likelihood of it being required to control other devices at some future point. If the answer is that it will definitely not, then there is no need to spend the extra money on a flash with master device capability.
Anyone serious about photography is going to gain some benefit from the decision to buy an external camera flash. An external flash unit will offer more lighting power, as well as the ability to direct the extra light. The superior power and control of an external flash are easily harnessed to improve image quality. The larger power sources of external devices also mean improved battery life and recycling times. In the real world, this translates into more time taking shots and less time wasted tending power sources. Anyone looking to get more professional results from their camera should have an external camera flash high on their wanted accessories list.