How to choose a detachable external camera flash

Pretending natural light is not easy when the conditions require you to use the flash and you don’t want the viewer to recognize it. However, with a detachable external camera flash and a little effort, you can achieve this and the results can be surprisingly good.

Not all Flashes are created equal

It is fair to say at the outset that not every flash is a good flash. Probably the biggest difference you will find between built-in flashes and on-camera external flash units. The built-in pop-up flashes have one major disadvantage, which is the impossibility of directing the flash, but on the other hand, their presence in the camera is an opportunity for many beginner photographers to try working with flash and you can also use it to fire an external, detachable flash or a smaller, compatible speedligt.

Advantages of external flash Units

Main advantage is the possibility of directing the flash to our liking thanks to the positionable head. This also goes hand in hand with the significantly higher performance of external camera flashes. This is indicated by the Guide Number (GN) for internal flashes reaching about 13 GN, the detachable flashes start somewhere around GN 20 and end somewhere around GN 80 in the case of powerful professional external camera flashes. 

Disadvantages of external flash units

And what is the disadvantage of an onboard flash? Theoretically, there is none, from a purely practical point of view it is the weight, which translates into the weight of the whole kit with the camera and also the necessity to have at least two sets of batteries to use the flash.

When to shoot with a flash?

The answer to this question is very simple, whenever you need to get light into a scene and there is no other way to do it without the photo losing the intent. Most often you can’t do without a flash in studio photography, and you will also use it often in portrait and wedding photography. When recording sports, the flash will be a useful tool (especially in the halls) and of course also social and documentary photography.

Camera flash for beginners tutorial. Using external light in flash fotography.

In each of the photo genres mentioned above, flash lighting will play a slightly different role, and most of the time they need to use it will force you to use specific exposures – for example, a higher aperture in low light to increase the depth of field that cannot be achieved in any other way. We will talk about aperture, exposure, and shutter speeds later in a separate article.

When not to shoot with a flash?

The flash is your friend but there are some situations when the usage of flash can result in poor digital photos. For example, when the object is too close to or too far from the digital camera the flash is practically useless. In certain situations, the flash can create unwanted shadows in the photo. A common fact is that flashes sometimes cause the exaggeration of details – e.g. when shooting a digital photo of an older person the skin wrinkles and imperfections details can be overly detailed.

When using the flash it is good to know its effective range.

Camera flash range. What is the effective range to shoot with a flash?

Digital camera’s flash units have a certain effective range. This is a limitation of how much light energy the flash unit can emit. Internal flash units usually have a shorter range than external, detachable flash units. If the object in the photo is outside of the flash range – the flash will not be effective and the object will be dark.

On the other hand, if the object is too close to the flash unit or the flash unit emits too much energy the object will be washed out. If your object is outside of your flash unit effective range you should turn off the flash and use slow shutter photography preferably with a tripod or another stabilizing mechanism.

If your flash unit allows the setting of the light power that will be fired (usually by setting the distance to the object) – make sure that it is set right to prevent washed-out objects.

In some scenarios, there will be enough ambient light to take a digital photo but without the usage of the flash, the digital photo quality will be very poor. In such a scenario, if the camera is left on the automatic flash mode it will not fire the flash. For example daytime photography with an object that is shadowed. If the object is wearing a hat it can create shades on the object’s face or when the object is lit from the side the object’s nose can create shades too.

Putting the flash in manual fill-in mode will force the flash to fire. The flash will lit those shadowed areas and prevent the shades in the final digital photo. The object of course must be in effective flash range.

Another example is an object that is lit from behind such as when taking a digital photo of an object against a sunset. Without a fill-in flash, the photo will likely be just a dark silhouette of the object.

Continuous lighting vs a Flash

The alternative, of course, is the continuous light source, which today is already at a very high level, and you can buy an LED panel of very compact dimensions with the ability to change not only the intensity of the light but also the color temperature, and all this still powered by a battery. 

However, constant lighting is the domain of video recording in particular, where constant bright light source makes much more sense. In the case of photography, perhaps only a powerful reflector aimed at the ceiling can be used to create ambient lighting.

By reflection or through a diffuser?

Although an external camera flash unit will offer more output, this does not mean that its light should blind the subjects. The higher flash power is available here to create sufficient ambient, natural light of the scene for a short moment.

Turning the flash towards the ceiling, from which the light bounces and diffuses, results in a soft level of brightness without harsh shadows that is much more pleasant and natural both in intensity and in its top-down direction, much like the sun shining down. The ability to turn the reflector and bounce the light off the ceiling or wall will help to make the photos look more natural, without harsh shadows.

If you find yourself in a situation where it’s not possible to shoot with the reflection against the ceiling, there is no choice but to point the flash towards the subjects, but always with the addition of a small diffuser or larger softbox. This is because it allows us to achieve diffused lighting that is much more natural, especially when we don’t overdo it with the flash output.

A diffuser for an external camera flash is usually included in the accessories. A less used but practical solution is also the combination of flash and diffuser plate, where usually the flash is placed outside the camera and the diffuser plate then directs its light where it is needed. In the case of outdoor photography, the reflective plate can even replace the flash itself in some situations.

What about the universal flashes for every brand?

Although less common, you may still come across universal flashes that have only one center contact, which is used to fire the flash regardless of the brand of camera. When working with such a flash, you need to be in constant control of its settings and project your own camera settings onto it, which can often be quite tedious. The disadvantages of such a flash are the need for full manual mode and the fixed and relatively long sync time of around 1/200 s.

TTL (through the lens) flashes

A more efficient way is a TTL flash, which is selected according to the camera brand and features multiple contacts on the hot shoe, so it is able to communicate with the camera and adjust its settings to the exposure values just selected. The flash adapts to the selected focal length in the same way, if it has a zoom head I definitely recommend choosing one of these models.

When the light is very low or you need to shine against really harsh sunlight, a high power output flash (e.g. GN 80) will come in handy, so it can easily serve as an alternative to studio flashes.

Which parameter should you choose according to? 

Clearly by performance, where the higher means the better. In general, a guide number between GN 55 and 60 can be recommended if you intend to shoot in direct sunlight. Lower light output is more suitable for indoors or to lighten the scene for product photography.

The second most important parameter is the zoom range of the flash head, which is usually between 24 and 105 mm, which is usually sufficient, but if you would like to shoot with longer focal lengths around 200 mm, the flash selection should be adjusted accordingly.

Last but not least, it will also depend on how you want to trigger the flash unless it’s mounted in a sled on a digital – on some cameras, this is possible using the remote flash control. Another option is to fire it using an internal flash whose flash is detected by the optical sensor of the detachable external camera flash – the downside is that the latter has to “see” the flash of the internal flash.

By far the best and most versatile solution is to use a standalone wireless launcher, which is very reliable even over longer distances and allows you to control the triggering of multiple external camera flashes simultaneously if required. In terms of brand, we definitely recommend sticking with the same manufacturer as your camera.

Is an inbuilt camera flash really useless?

Definitely not, you just need to know how to use it. Even though it’s small, low power and its light is very close to the lens, plus on its axis, you can definitely use it. 

It is very common to use it when you are shooting, for example, a portrait in a backlight and you need to illuminate the subject’s face. In this case, an internal flash will suffice, but you need to reduce the power and ideally use a diffuser.

This can either be a small, snap-on flash, or you can actually use any material that diffuses and softens the emitted light like baking paper or non-woven fabric. However, in these cases, you should expect a higher light absorption and therefore you will need need to increase the power.