Advice on camera flashes
In which situation are you going to use the flash?
This question is actually easy to answer: namely, when the internal flash of your camera does not meet your needs. But what can an external camera flash or, what a pop-up flash can not do? With a built-in flash, you can not adjust the direction of the light, so the flash always comes from the front. The head of an external camera flash is often rotatable and tiltable. This is possible with an external flash. The internal flash has a limited flash intensity. Subjects at a greater distance will not be properly explained. The external flash units are a lot more powerful and have various options for dropping the flash light on your subject.
What are you going to use the flash for?
One of the most important features of a camera flash is that it is a lot more powerful than an internal pop-up flash. The strength of the flash light is measured with the guide number. The higher this guide number, the higher the light output of the flash. To know exactly how big the light output of the flash is, you can divide the guide number of the flash through the desired aperture. A flash with a guide number of 28 can illuminate a subject at 5 meters with the use of aperture f / 5.6. Because 28 / 5.6 = 5. Incidentally, this calculation applies to an ISO of 100. If the ISO value is doubled, the guide number increases by a factor of 1.4. The guide number is a handy way to determine the distance to which a flash can be used.
Most of the flashes can communicate with the camera so well that you almost no longer need to set up as a user. The flash and camera use a technique called DDL. This literally means "By The Lens" (or TTL, "Trough The Lens"). The camera measures the amount of flash light required to properly illuminate the subject. If you set the flash to this position, you will still need to set a few manually. There are also flashes that can only be adjusted manually. This requires some practice, but these strobes are often a lot cheaper.
The intensity of the flashlight can be regulated in a certain step size. Here 1/1 is the most powerful flash that the flash can produce. Often 1/128 is the softest flash you can use. You then use 0.8% of the maximum flash output. The step size between them determines the extent to which you can set the flash.
To determine the direction of the light, almost all camera flashes can be rotated or tilted. This way the light no longer comes exclusively from the front and you can avoid hard shadows. A simple way to do this is to indirectly illuminate your subject. You can do this by tilting the flash up or down and letting the flash light reflect through the ceiling or a wall. We call this technique "bouncing". Are you using a flash to illuminate subjects up close, such as with macro photography? Then you can use a ring flash or special macro flash. These macro flash units are mounted on the lens with an adapter ring to get as close to the subject as possible.
How can you influence the flash light?
To get even more out of your flash, there are a number of accessories that help you to create the right kind of light. With a diffuser you soften the light when you want to flash instantly. This way you get a wider beam of light that provides less shadows. The softbox is a successor to the diffuser. With a softbox you create very soft light which produces almost no shadows. You can also easily reflect the flash light by using a reflection screen. You decide where you place the screen and at what angle. In addition, reflective screens are available in various colors, so give a colorful interpretation to your photo.
Can you also use the flash separately from the camera?
Sometimes you would want to place the flash in a different location than on the camera. Is that also possible in a simple way? Yes, you can experiment with "strobist". Strobist is a collective name for everything that has to do with flash units that are used separately from the camera. To get started with strobist you have to control the strobe while it is not mounted on the camera. This can be done in a number of ways.
Some camera flashes have a so-called "slave" function. This means that the flash sees a flash in the neighborhood. The flash reacts to this by flashing at lightning speed. It is important that the two strobes can see each other. You can also connect the camera flash with a flash sync cable. This cable sends a signal to the flash when the shutter release button is pressed. You are then bound to the length of the cable. The most advanced method is with a transmitter and receiver. The flash is placed on a receiver, a transmitter is mounted on the camera. You then use a remote trigger. It no longer matters where the flash is placed, because the transmission signal is very strong. Depending on the number of channels of the transmitter, several flash units can be controlled in this way at the same time.
In some cases you can continue to use the DDL technique. However, this saves per combination of camera and flash and the way of operation. In most cases, you will have to set the flash to the desired flash output.
Original or third party?
The most camera manufacturers also make strobes. But there are also a number of manufacturers who specialize in making camera flashes. So you have a choice of different brands. It is not the case in all cases that a flash of the camera brand is also better. It is true that a brand combination guarantees a seamless cooperation between camera and flash.
Do you want to use a different brand of flash? See if it communicates well with your camera. It may be that not all settings are supported and that you have to set the flash manually.