Why buy an external camera flash? are built-in flashes insufficient?
Photographers who buy an external camera flash do so because they are not happy with the performance of their camera’s built-in flash. An external flash is mostly for DSLR cameras and most people buy it to deal with the issue of light reflections that come from your object (e.g. the person you are shooting) and all of the unpleasant distortions caused by light and shadow imbalances.
Let’s list the most common issues photographers face when using a built-in camera flash:
- Red eye that happens when your object stares straight at the light source (the flash, in this case).
- The light is too harsh and always comes from one direction – the center of the camera.
- The flash covers limited space and always leaves stark contrasts between lit and dark areas.
Let’s put it this way: pictures just don’t come out looking so great when people use built-in flashes.
A camera flash is not the most important piece of equipment to buy, though. You should probably think about buying good lenses or even a tripod; however, buying a camera flash is something you will very likely consider at some point in time.
An external camera flash will let you aim the light beam at the ceiling, which would produce a softer light that will bounce off the ceiling in a downward direction. You could even set the light to hit a nearby wall (depending on the maneuverability of your flash). On top of that, an external flash can supply much stronger light that will allow you to shoot objects that are further away without leaving them under-exposed (i.e. your object will not be too dark).
How is the light intensity determined?
Light intensity is determined by Guide Numbers. The value of these numbers represents the aperture times the maximum distance the camera flash will be applied to (in feet). Here’s an example: if you choose the aperture f16 for an object that’s 10 feet away you would need a guide number of 160 (which is 10 times 16). Want to translate that into the metric system? Divide the feet by a factor of (approximately) three. Since you’re probably not going to measure distances every time you want to take a picture, you will be able to eyeball the distance with a little bit of experience.
The remaining question is: how strong a camera flash should you buy? Our answer is: try to get the strongest camera flash for the amount of money you’re willing to spend. And remember that a stronger flash means higher Guide Numbers.
How does the external camera flash work with the rest of the camera’s components?
A camera flash interacts with and complements other components responsible for light exposure.
- Aperture – as you probably already know, the opening and closing of the aperture allows for more or less light to get in. Since the flash is a light source, the larger the aperture is the more light from the flash will enter the camera, and the smaller the aperture is the less light from the flash will get in. Think about it this way: if you could close the aperture completely, it wouldn’t matter how strong your flash is. No light would go in. Therefore, for the flash to work efficiently, you need to open the aperture. A tip: if for some reason you use a smaller aperture, the flash might compensate for that and increase its intensity causing excess light and distortion.
- Shutter speed – the shutter speed determines the amount of time in which the camera lets light in. The slower the shutter is, the more light will get in. The important detail here is that the flash works much faster than the speed of the shutter; therefore, leaving the shutter open for relatively long will not have any influence on the amount of light that the camera captures (at least not light from the flash). Also, since the flash will light closer objects better than distant objects, you’d want to set your shutter speed based on how lit you want the photo’s background.
What else can you do to improve flash photography?
Here are several other methods you can use to improve the effectiveness of your flash:
- Change your location relative to your object. One idea would be to use a wide-angle lens, and move closer to your object. This will better light your object.
- Pick a higher ISO, which will automatically brighten up your pictures. This will also let you stand further away from the object when you just cannot stand near enough to light the object with the flash alone.
- Use a diffuser – this is a device that installs on the flash and softens the light. It is especially useful in situations that require pointing your flash directly at your object.
- Use a reflector – this is a device that softens the light intensity and sheds the light on the object in a more balanced way.
When can you use your camera flash?
- Dark environments – this is obviously the flash’s main purpose - it lets you shoot at night and in dark places. Play around with the shutter speed, the aperture, and the ISO to make sure that you are utilizing all methods of brightening up your photos and that you are using your flash effectively.
- Compensating for exposure – if, for example, you want to shoot with a slow shutter speed and you still don’t get enough light, you’ll can add more light to the photo with the flash to make sure that your object is well lit (you’ll be surprised - it won’t be easy to tell that you used a flash in the photo).
- Macro photography – when you’re doing macro photography with a relatively small aperture, you will most likely need a flash, and a flash is a must if you are using a macro lens.
- Freezing your object in dark settings – when you shoot in a dark environment and you don’t want your object to get smudgy or blurry, the flash will provide you with sufficient light and remove the need to use a very long shutter speed.