Introduction To Different Types Of Flash Units

I often receive requests to discuss, and write something about camera flashes. Often seen as complicated. That learning about them scares many people. Because of the unfamiliar terminology used, and the effect of the flash is difficult to predict. Even if you’ve already practiced using it. If you want to make the most of using your flash. The results can be unpredictable, and a lot of people give-up in learning more about it.  But that’s a shame, because a flash offers you many of the same capabilities as natural light.

Flash Photography

The primary requirement for photography (which means “writing with light ‘) is that, there should be light. No light , no picture. Unfortunately, sometimes we have to shoot pictures in less than ideal conditions.  I am referring, of course, to  shooting locations with low light.  In such cases, the use of a flash is  necessary, or the only option. But using this tool, can present new creative possibilities.

That is why, this article is just the first in a series, an introduction to the world of design flashes. In the course of the year,  I will discuss, and give more attention to the different forms of flash technology. The article starts with a sturdy piece of theory. Then  I will discuss the choice for the flash, and some creative applications.  In the next articles,  I’ll delve deeper into the subject of flash photography.

Artificial Light

It provides the strongest light possible for it  to enter the camera sensor, and prevent blurring. The color temperature of the flash is similar to daylight, (neutral 5500 Kelvin). The duration of the flash is very short, up to 1/1000s, but enough for the camera to catch the light. It determines when the flash should fire. The aperture must be fully open before the flash responds.

This is important to know: each camera has a maximum flash-sync-speed. For the cheaper models this is 1/90-1/100s. The more expensive models, usually up to 1/250s. Modern cameras have two moving curtains. First, the front curtain, releases the lower part of the sensor. Followed by the second one, which  releases the upper part of the sensor.

The speed with which these curtains move across the image while shooting, determines how much light reaches the sensor. Depending on the shutter speed, there is a certain time when the entire image is visible. This is when the flash will fire. At high shutter speeds, the flash will not fire. With a single flash, the full picture will not highlight. With older cameras, a dark plane comes into the picture. Newer cameras automatically reduce the shutter speed to correspond to the flash-sync speed .

Flash Range

Actually, there is not one, but two very fast flashes behind each other. One measures the light, which gives data to the  camera. More expensive camera-flash combinations have  an option for high-speed sync.  Instead of a single flash for exposure, multiple firing of the flash  can cause  higher speeds. The flash’ range of light has a limitation. The rule is, that at twice the distance, the light decreases exponentially.

To make the distance 2 x longer than  the light, but 1/4 (2 to the power of 2) of the original strength. To make the distance 1/2 shorter than the light 4 x stronger. The same applies to 3 x longer = 1/9 or at a shorter distance, 9 x 3 x stronger. Since the built-in flash  works up to 3 meters and that of an external flash 15-20 meters. You can also  see the obvious reason why it makes little sense to use flash during concerts or sporting events, you only end up lighting-up the area around  your neighbors.

Flash in Landscape Photography

Also for landscapes, using flash only makes sense if your main subject is relatively close to the camera, such as a tree or a dilapidated shed. To what distance a flash exposure can reach,  is expressed in the ‘ guide number ‘, this is one of the distinguishing values in selecting  a specific flash. The modern flashes’ course limit depends on the lens and focal distance you use.

The Area In Front Of The Lens

If you use  a 200 mm telephoto lens to photograph, it makes no sense to use flash with a wide circumference of 20 mm of the scene. As much as possible, all the power requires to be focused in  the area in front of the lens. Most flash units are therefore equipped to compensate  for this, and considers the measurement of your lens, usually from 20 to 100 mm. Outside the flash course, you will see light waste, those parts are less exposed and may be darker in the photo.

Because the flash fires so fast when using a slow shutter speed,  not enough light reaches the sensor. You can set the camera, usually through a ‘ custom function, ‘ so that it will use rear curtain sync. This means that the flash will not respond immediately, after the front curtain follows, but just before the rear curtain comes into the picture. This gives the effect that  that the camera is panning with the subject, but the subject is completely stationary. An example is a car that’s not moving, showing a long stripe of the red tail light, at the back (making the car appear as if it’ speeding. ) This technique requires some practice, but when successfully done, the result is very spectacular.

Built-in Flash

This article is not about flash in general, but specifically on  flash units. Loose flash units that you attach to your camera are removable. You might ask, ” But I already have a flash, which  sits right on top of my camera, why do I still need another flash? ”  The built-in flash on most cameras, is not very powerful. Its effect, therefore, is  relatively limited. Subjects farther than 3 meters may not be exposed. It’s also located on top of the camera, which increases the chance of causing ‘red eye’ in portrait photography. This can be countered by the flash to set up or run, but this is not possible with the built-in flash. These reasons shall also explain why the semi-pro, and professional camera models in general, often have no built-in flash. Photographers who are familiar with these models always find alternative ways to supply  light.

The studio of a photographer is generally filled to the rafters with lamps, backgrounds, reflectors, diffusers, etc., which are all devices that allows one to manipulate the light. But on the other hand, many photographers, and amateurs do not have these kind of equipment at their disposal. That’s why you have to  choose carefully a flash design and make the best use of it. They are easy to carry, flexible, can flash at an angle, (thanks to the swivel head) and , can be used as stand-alone.

Choosing a Flash

To properly select the right kind of flash design,  think about the purpose it will serve. Virtually every camera manufacturer has their own line of flash units which can be  connected to SLR cameras. There are even compact cameras with provision for connecting an external flash, or ‘off-camera’ flash.

Canon 580 EX II Flash

Canon’s Speedlite Flash units have EX in their type designation, which are based on  Nikon Speedlights, and have SB in the type designation.  Just as with cameras,  there are different models that have different capabilities, and target groups. The cheapest model is for the entry level cameras, and costs between € 100-150. The mid-priced model is around € 200 and the most expensive model is about € 400. The biggest differences are in the flash power (the range can sometimes be 15-20 meters,) and the speed with which the flash is ready to take the next picture. More expensive flashes can control multiple flashes, and also the power source of the flash can differ.

For example, comparing the Canon 430 EX and 580 EX,  you will see that the 580 EX recharges much faster and has longer battery life. The range is also greater than that of the 430 EX. For the 580 EX, quality does not come cheap, (since it’s the most expensive model. ) Almost all flash units make use of (rechargeable) AA batteries, but you have the option  to use spare batteries, which gives you much longer time to work with  your flash.

Your choices of  flash are dictated by your budget, and the purpose for which you want to use them.

Through the Lens (TTL)

This type of flash is generally placed on the ‘ hotshoe ‘ of the camera (it can also be connected using a ‘ PC Sync ‘ cable or triggered by a wireless transmitter). The hotshoe is standardized, and differs according to its purpose. Each camera brand has its own contact points, and electronics, but  flashes made by other companies  can also be used as long as they are compatible with it. These are the things you have to look out for if you are looking for a flash. However, the features included in those exclusively made flashes by known camera manufacturers are better and more helpful in terms of bringing out the best in your photos, and taking full advantage of your camera’s features.

Both Nikon and Canon have a proprietary exposure program that will help you get  correct exposures with the flash. Canon calls the system E-TTL, while Nikon has  iTTL, under their Creative Lighting System. TTL stands for ‘ through the lens .’ The camera shows the measurement to the flash, which then applies the correct exposure strength.

Preference Program

A kind of machine stands for the flash . The effect that this automatic setting gives , depends on the preference program (shutter speed, aperture preference, preference, etc.) that you use. One of the reasons why flash units and camera software settings can be  confusing to newbies.

If you don’t want to apply your camera’s automatic settings, you might not like your camera’s performance.  In this case, you can change the flash power , with the + or – options on the camera. More and more cameras, also offer the possibility to change  the flash  settings via the menu. If you want to override the auto-settings and to have complete control over them, then you can manually operate the flash completely. The main choice you can make is in the power of the flash. Depending on the flash, you can adjust it to full-power, to 1/128th of the force. It is Important to take into account the distance from the subject, so you have to do calculations for accuracy.

Exposure in Balance

When selecting a flash from a number of choices, the effect that the flash creates depends on this choice. The power of the flash has a direct relationship with the shutter speed of the camera. The more powerful the flash, the faster it takes for enough light to enter the sensor, and the shorter the shutter speed is.

Light moves over a distance, the farther away the light is, the longer it takes to reach the sensor.  If you have a very fast shutter speed, you will be relatively using more flash power, and relatively little ambient light on the sensor. As a result, it can appear that the background of your subject is completely black, while the subject is in stark contrast with the environment.

By using less flash power, you also get slower shutter speed on the camera, so this will give the light  more time to enter, allowing more ambient light to reach the  sensor. As a result, its surroundings, and  flash appear more balanced. A higher ISO sensitivity or a wider aperture can compensate for the darkness of the background.

Bounce Flash

When you  focus the full power of the flash directly at your subect, almost all details are highlighted or ‘blown-up.’ This gives the  face an unhealthy appearance, creating a harsh contrast of  white areas and dark shadows, (also referred to as ‘hard’ lighting.) By aiming the flash head to the ceiling, a wall, a reflector, or even a white t-shirt as a focus, the light takes a detour before it reaches your subject. This bathes the image with ‘soft’ lighting, causing  a smooth, and soft transition between dark shadows and bright areas. As a result, the light gives your subject  a more natural look,  which gives you a more pleasant picture.  A white surface is ideal, since this will reflect a neutral color.

Unlike if  a red wall or a green tablecloth is used to reflect light, you will see shades of these colors thrown back at your subject. There are reflection screens that come equipped with bright golden color which you can use in creating a warm glow around the subject. Using a diffuser, (a neutral colored piece of plastic to soften the light,) causes the light to spread out more, creating a more pleasant exposure.  If  you have no option to use another object to reflect the light, then this can at least help. There are several vendors that also offer complicated constructions and  have figured out to manipulate light in such a way that it creates some unusual effects.

Loose Flash

Bounce Flash is in extremis  implemented by the ‘ strobisten ‘. A popular name for photographers using one or more intentional flashes (strobes) that highlight a portion of the subject . It is revolutionary that with these simple means , a studio effect can be achieved. Strobes are placed to the left or the right of the subject,  against the background, or focused on the hair (hairlight), possibly with various colored filters. Bounce Flash can be done by connecting the flash with a PC Sync cable to the camera, and then it flashes from one corner of the camera, to direct the light on the  left or right of the image, instead of straight forward. The scope is limited, however, and you run the risk of errors.

Another option is to control firing of the flashes from the camera via a wireless transmitter. Each flash has an infrared receiver. One flash is set as the ‘ master ‘, while the other flash units are its’ slave ‘. The flashes don’t all have to be of the same type, as long as they are of the same brand.  So the more expensive 580 EX II will use up the battery power of 430 EX flash units.

The power of the flash can be varied, some flashes even have  the possibility to control the configuration of other flashes in groups, and individually. The advantage of this method is that the TTL functionality of the manufacturer is still being used. The master need not always be a flash, some Canon and Nikon models, also supply a channel directly on the hotshoe that can be connected, so that the master flash, as well as the slave can be used. This eliminates the need to purchase other flashes.


Infrared, however, has the disadvantage that there is a direct line of sight with the control flash, or a camera and that the distance is limited. In recent years, this transmitter/receiver combinations that forward the instructions via radio waves  (wireless) , have been made  available in the market. Examples are the Pocket Wizards, and the radiopoppers. These are fairly expensive solutions, sold on ‘ eBay, ‘  which have become popular in recent years.

Manufacturers in Hong Kong, and Taiwan produce  these wireless transmitters at a fraction of the price of the high-end ones. Usually they work in 7/10 cases, more than enough  for the average amateur. An example is the Cactus V2s. You can order your the transmitter/receiver combination directly from Asia, which costs no more than € 20, a fraction of the € 250-300 that you  normally shell out for a transmitter/receiver. Recently, popular shopping sites have started offering these transmitters which can be ordered online. You pay slightly more (but still much less than the professional stuff) but you’ll be more sure about delivery time, and getting support. As long as a transmitter has no Dutch government approval, it usually is not recommended for professional use. If you do this, then you’re seconds from committing a violation.


The use of flashes is not allowed everywhere. Most museums, concerts, and sporting events  often prohibit  flash photography because they interfere with the experience of other people, and can be distracting. The effectivity is also usually limited, since the photographer is too far away from the action, to really benefit from the flash. There is no option but to turn off the flash, set your ISO higher, use a wider aperture,  hold your breath and make the best of it.

I hope that this introduction has given you already a good idea of the (IM) possibilities of design  flashes. As I mentioned before, more attention to specific flash applications will be discussed in my future articles.

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