Flash synchronization
As flash synchronization or sync flash automatic will synchronize the firing of a flash unit with the end of the closure , respectively. It ensures that the shutter reveals the full film window while the flash is on.
Methods
There are three different methods of flash synchronization.
- M synchronization
- X synchronization
- FP synchronization
This distinction is independent of the type of transmission used for the signal. These are only terms for standardized processes and technical requirements or conditions. They are used both wired and wirelessly.
application
By definition, there are no dependencies on special contacts or sockets. For various reasons, the manufacturers of the cameras only partially implement these methods in their devices or only offer them in certain price ranges.
Modern system flash units of the widely used camera systems simplify flash photography through numerous automatisms and extensions such as wireless flash remote control, synchronization to the second shutter curtain and stroboscopic flash . It is possible to use shutter speeds that are far faster than the flash sync speed . Thanks to these extremely short synchronization times, fill-in flashing is possible in almost every situation.
If the sync socket is used to connect studio or special flash units , no automatic functions of system flash units can be used, as these do not allow the transmission of additional control information. The FP synchronization cannot be used in this case either. This problem is solved by using special adapters for the accessory shoe or wireless control with special master flash units or dedicated transmitters.
M synchronization
In this case, the M stands for 'medium time'; with this type of synchronization, the flash is triggered even before the shutter is fully open. Since the chemical process of the combustion has to get going, this ensures that the shutter of the camera is fully open when the maximum brightness of the glass bulb is reached. This is the prerequisite for flashing with central shutters with exposure times shorter than 1/30 of a second when using flash units with flash bulbs .
X synchronization
The X in the name refers to the noble gas xenon , which is used in the electronic flash tubes . The flash fires only after the shutter is opened . With this method, the flash sync time is between 1/60 s and 1/300 s for cameras with a focal plane shutter in 35mm format, and up to 1/500 s for some digital cameras with a smaller sensor. These values depend on the structure of the lock and the design of the camera . For cameras with a central lock, shorter synchronization times of up to 1 / 2000s are possible.
Provided that the light duration of the flash bulbs is observed, it is also possible to use this together with an X-synchronization. The shortest flash sync time that can be achieved with flash bulbs is between 1/30 s and 1/60 s.
Normally, the X synchronization is transmitted via the center contact in the camera accessory shoe . For applications in the photo studio, flashes that are further away can also be controlled via an extra connection. Older cameras with additional FP synchronization either have a switch for the type of synchronization or separate connection sockets.
FP synchronization / short-term synchronization
The short-term synchronization or high-speed synchronization (HSS) was developed to enable flash photography with exposure times that are shorter than the flash sync time . This operating mode is also sometimes referred to as (Super) FP mode or FP mode , where FP comes from English and stands for focal plane shutter ( focal plane shutter ). This synchronization is based on slow-burning flashlights that burn down with largely constant light output, such as. B. Sylvania M3 (WZ) coordinated. The M2 from the same manufacturer, which looks the same, is unsuitable because it burns down faster and not evenly.
The technology
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At shutter speeds below the flash sync speed is plane shutter fully open at any time. Since the flash time is considerably shorter than the shutter speed, there would be a partial exposure on the released area of the medium. By emitting several flashes in a row ( stroboscopic effect ) or by prolonging the emission of a single flash during the entire shutter speed, the entire medium is evenly illuminated. However, both methods result in a significant reduction in flash output because the flash has to be fired several times or over a longer period of time and much of its output is blocked by the shutter curtain. Most camera manufacturers implement this flash mode with the stroboscopic flash . Olympus sometimes uses the extended single flash in its digital e-system. As a result, fast movements are represented by a wiping effect corresponding to the movement sequence , while the movement sequence appears frozen due to the stroboscope effect . The single flash enables a more dynamic looking photo. With the stroboscopic flash it can happen that partial movements are not completely reproduced in the case of unfavorable overlaps between the exposure and movement sections. With both techniques, the movements are shown slightly offset in time according to the exposure sections.
Applications
By reducing the shutter speed, the aperture can be opened wider. As a result, it is also possible to influence the depth of field in a more targeted manner in flash photography .
The high-speed synchronization is also suitable for brightening the subject in very bright surroundings or in backlight . A short shutter speed prevents overexposure of the surroundings.
Due to the already mentioned reduction in flash output, high-speed synchronization is not suitable for distant subjects.