Transforming light into life

A complete lack of modeling light can result in portraits that are as flat as the photographic paper itself. The photographer failed to place the light sources at strategically favorable points to achieve a three-dimensional or modeling effect.
The following situation indicates how flash units can be appropriately arranged to achieve a modeling effect: A portrait is to be illuminated by two flash units. The rim light should be one stop stronger than the main light. The film’s rated speed is ISO 100/21°, and the two flash units used each have a guide number of 58.

Ballett Mädchen
The flash unit was removed from the camera and set up to the right of the model.

The flash unit was removed from the camera and set up to the right of the model.

Settings in manual mode

It is a matter of course that the light emitted by a flash unit and reaching the subject will change when its distance in relation to other flashguns is increased or decreased:

Distance to subject x 0,7 increase of 1 f-stops
Distance to subject x 0,5 increase of 2 f-stops
Distance to subject x 1,4 reduction of 1 f-stops
Distance to subject x 2,0 reduction of 2 f-stops

In view of our exposure situation, this means that by a selected camera shutter setting of 8:
Distance to the main flash unit for camera shutter 8:
Guide number 58 : Shutter 8 = 7,25 m
Distance to the edging light flash unit for one shutter setting higher:
7,25 m x 0,7 = 5 m

The relatively large lighting distances for normal room conditions can be reduced by using partial lighting levels on the mecablitz. Many Metz mecablitz flash units are equipped with such partial lighting levels.

Settings for computer-controlled flash units

When working with automatic flash units it is not necessary to set up the individual flashguns at precisely calculated distances. They can be arranged at any point within the working range of the adjusted automatic apertures.The following rule applies to the light output of the individual flash units in relation to each other when working with an automatic aperture:

The same automatic aperture number and reference shutter number = normal lighting
Higher automatic aperture number than the reference shutter number = stronger light
Lower automatic aperture number than the reference shutter number = weaker light

Here, too, the computed reference aperture is the camera aperture. Consequently, the following settings have to be made for a selected camera aperture of f/8:

Main lamps:
Computer shutter 4, lighting distance: 0,1 ….. 14,5m
Lamps for edging light:
Computer shutter 8, lighting distance: 0,1 ….. 7,25m

Position your flash units in such a manner that the light from one strobe does not directly fall on the sensor of the other, as this would prematurely switch off the light sources.
Trigger your flash units either via a sync cable or wireless with the mecalux 11 Metz mecalux 11 slave trigger unit. The Metz remote TTL flash system will greatly simplify exposure management. Please refer to our tip “off-camera flash”.
Modern flashguns feature partial light output levels in the manual mode. This enables the user to easily increase or decrease the lighting power without having to change the flash-to-subject distance. It also overcomes the problem otherwise associated with short flash distances.