Who is faster the flash or zoom

The Lightning

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Short version:


  • independent light source
  • Color neutral
  • extremely short exposure times possible
  • directed light
  • enables contrast reduction through fill-in flash
  • Synchronous times must be adhered to
  • uneven depth illumination
  • directed light
  • creates hard shadows and high contrasts


Lightning and its application is a very broad topic. In order to at least narrow it down a bit, I will not go into (professional) flash systems for the studio area in this context.

If you want to take photos and there is not enough light, you can take a flash. This backup light function is what most people aim for when they use a flash. However, it is precisely because the flash is used in this way that most of the problems arise. These lead to the fact that lightning is a wallflower in (amateur) photography.

In order to redeem lightning from this shadowy existence (!), We have to learn to deal with it. Above all, it is important to learn what lightning can and cannot do. Otherwise you will always be dissatisfied with your flashed photos.

Since the subject of flashing has a lot to do with (considered and controlled) trying out, especially at the beginning of the personal learning phase, I have developed a course for beginners precisely for this purpose. You can find information about this speed course for beginners, which takes place in one evening, at http://www.fotoschule-ruhr.de/kompaktblitz.php

First approach
So we should take a closer look at the lightning bolt first. Each flash unit has a reflector through which the light emerges. Some of these reflectors can be tilted, swiveled and zoomed.

Zoom reflector

By zooming the flash, it is adapted to the angle of view of the taking lens so that the whole picture can be illuminated, but no light goes "wrong" either.

If the flashing angle of the flash is too small, only part of the image is illuminated and we get darkening at the edges of the image.

If the light angle is too large, some of the light does not come into the picture. It's lost and the energy used to create it is wasted, so the batteries run out faster. In addition, the "range" of the light is reduced and the flash has to charge longer than necessary.

The reflector is often very small. This contributes to the unpopular harsh lightning shadows. And the fact that this reflector is usually also close to the optical axis (receiving axis) further exacerbates the problem.

Before we get into the intricacies of flashing, there are a few terms that need to be clarified:

The synchronous time
The sync time is not a property of the flash, but of the camera.
It is primarily important if you are using a focal plane shutter camera. This includes most SLR cameras, but hardly any of the compact, bridge or viewfinder cameras (these usually use a central shutter in the lens). A focal plane shutter works similarly to a roller blind or a roller shutter on a window. There are, however, two roller blinds. After you have cocked the shutter, the first shutter curtain is in front of the sensor or film. When you release the shutter, this curtain moves to one side and reveals the image window.
After the exposure time has expired, the second shutter curtain, which was previously rolled up, closes the window again by following the first. When the buckle is cocked, both are returned to their original position.


With long exposure times (this varies depending on the camera model), the shutter releases the entire image window for a shorter or longer period of time. But when the times get shorter, this type of shutter is too slow.

In order to still allow short times, the second curtain is sent after the first one shortly after the start, before it has reached the end of the window. So there is only a slit across the image area. The shorter the time, the narrower the slot.


Short exposure times produced in this way have some disadvantages, especially when it comes to flashing. The flash shines extremely briefly (often only in the range of "tens of thousands" of a second). So if it were used with the camera for such a short exposure time, it would not be able to shine long enough to emit light until the narrow exposure slit had moved completely over the entire image. It would only flash for a brief moment, so that the flash exposure could only affect a narrow strip of the image.

Flash if the shutter speed is too short


Here the focal plane shutter moved from bottom to top (the picture is upside down in the camera), which is common with DSLRs. The selected shutter speed was probably only half as long as the synchro speed, which is why the slit is only about half the width of the image window.

You should only take photos with times when the entire image window is free. The shortest time in which this is still the case is the so-called synchronous time (depending on the camera model between 1/60 and 1/250 of a second).


However, you do not need to use the synchronous time for flashing, you can also choose any longer one, as the whole window is then "open" in any case.

For some time there have been cameras with the ability to flash for very short times. However, this is then the result of a function of the flash that makes it flash like a stroboscope (with significantly lower power) while the slit wanders over the image.

The automatic flash
While in the early years of flashing, the photographers always had to set the flash and the camera more or less laboriously using the guide number (see explanation below), later various automatic systems for the flash were developed. An automatic flash has a built-in flash exposure meter that measures the reflected flash light with a sensor and switches off the flash when there is sufficient exposure.

When flashing, the exposure is not regulated by the brightness of the flash (as with a dimmer), but by the duration of the light. With automatic flash it is possible, in contrast to a manual flash that is controlled via the guide number, to select the aperture more or less independently of the flash distance. (Of course, always within the range of options offered by the flash. Most of them have at least three apertures to choose from.)
With a few tricks you can still vary and fine-tune these settings, e.g. B. for fill flash. I'll explain how to do this later.

TTL flash
In contrast to the automatic flash, with TTL flash the light from the flash is not measured with an external sensor, but in the camera (therefore TTL: Through The Lens). While this is what is very practical, z. B. The extension factor is taken into account directly in macro photography, but the disadvantage is that fine adjustment of the flash for fill-in flash (will be explained later) is not always possible regardless of the film sensitivity used (depending on the camera).
In the meantime, various manufacturers have developed different TTL systems (including A-TTL or E-TTL) with which several flashes can be wirelessly controlled, even if they are remote from the camera. Going into this in detail would go beyond the scope of this photo tutorial.

The guide number
The size of the reflector gives only limited information about the power of lightning and its performance. There are several ways to measure and report this performance. In the area of ​​"small" flashes that can be used directly on the camera, the guide number is used to indicate the "power" of a flash. The guide number is the product of the distance between the flash and the object and the brightness achieved.
The brightness is indicated by naming the aperture that leads to a correctly exposed picture. This calculation is based on an assumed film speed of 100 ISO.

Cheating with the guide number
While you could previously rely on the manufacturer specifying the maximum guide number of a flash for a normal or even wide-angle focal length, nowadays it can happen that the guide number is given for a longer focal length.
Modern flash units often have zoom reflectors that adapt (usually automatically) to the focal length used.
If you then take photos with a light telephoto lens, the light can be focused more closely. And through this bundling, the flash can illuminate the photographed section brighter and it has a longer range. Definitely an advantage.
But unfortunately some manufacturers use the longer range with bundled light to calculate the guide number of their flash. This results in a sales-promoting higher guide number. Unfortunately, the lightning bolts can no longer be compared properly with each other.
If your subject is 4 m away and your flash is sufficiently bright for you to properly expose it at f / 8 with a sensitivity setting of 100 ISO, your flash will have a guide number of 32 (8 x 4 = 32).
Conversely, a flash with guide number 40 with a selected aperture of 2 at a distance of 20 m will achieve correct exposure with a setting of 100 ISO (40: 2 = 20).
And the exposure time?
The exposure time has no effect on the exposure when the flash is the only light source, apart from the fact that the limitations of the sync time must be taken into account.

If you make these connections clear, you will notice that the flash will illuminate the subject very unevenly in the spatial depth. Objects that are close to the flash become very bright, objects that lie in the depth of the picture may receive too little light to be adequately exposed. This gives rise to problems that are described on the following pages together with some suggested solutions. But before we get into that, here's a warning.
Many modern cameras, especially digital SLR cameras, do not get along well with old flash units. These old flash units work with very high voltages that can damage the cameras. Problems do not have to arise immediately. B. express by a creeping damage to the shutter of the camera. So you should play it safe and ask the manufacturer of the flash unit or camera whether the devices work together.

Blitz course
Since the subject of flashing has a lot to do with (considered and controlled) trying out, especially at the beginning of the personal learning phase, I have developed a course for beginners precisely for this purpose. You can find information about this speed course for beginners (which takes place in one evening) at http://www.fotoschule-ruhr.de/kompaktblitz.php

A live photography course (photography basics).
- with Tom! Striewisch, the author of the photo course on the Internet.

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More Information and registration for the photography courses with Tom! Striewisch behind this link.