Carlos Pereira received a qualification from the British Institute of Professional Photographers. He developed a successful business in the UK as a wedding and Portrait photographer. He received further training in the USA from Monte Zucker, a master photographer.
His Wildlife and Portrait photographs have been published in the UK and European photographic magazines.
He concentrates his photography as a travelling photographer and a teacher, offering his expertise as a nature photographer through digital books.
His vision has been moulded by the classic portraiture that was his business for a number of years.
Contrast control is what fill-flash accomplishes best
What is fill-flash?
Fill-flash means adding additional light from a flash unit to open up the shadows and lowering contrast. It can also do the opposite, that is increase contrast. If we have an external flash unit and place it on the same side from where the main light is coming from, we will increase contrast. This maybe done on an overcast day when the filtered light from the sun is too soft.
In FIG 1, the main light the sun is from behind the bird. If we do not add extra light, the subject's eyes will be dark with little detail. The shadow below the bic would be black. By adding some fill-flash we can open up the shadows and reveal detail.
How much fill-flash should be used?
What is the best contrast ratio?
The answer is not straight forward - it depends on the photographer and the subject being photographed. In modern portraiture the contrast ratio for a woman is less than for a man. However, in modern portraiture photographers often give both the same amount of contrast.
Example - if we are photographing a woman and if the main light exposes at f/8, one stop less, creates pleasant shadows - so the fill-light would be calibrated to give f/5.6. - FIG 2.
For a man maintaining strong shadows makes for a pleasing portrait - so, the fill-light would read f/4 - FIG 3.
These principles apply to wildlife photography. How much fill-light we use depends on a number of factors. We may even decide to equalize the flash light to the main light, (the sun) to have the same intensity.
An example of this could be in an landscape image where a point of interest in the foreground is dimly lit and by adding extra light we will emphasise it and balance the background light with the foreground, FIG 4 - The small plant nearest to camera received fill-flash with the same strength as the ambient light.
Too much Light is Bad
One of the major faults in the use of flash is adding too much. This can burn out fine detail from the image. Adding flash from off the camera's axis can also create unwanted shadows and/or highlights if it is not placed properly in relation to the main light and subject.
In photographing wildlife, if they are within the effective flash distance, I use just a hint of fill-flash to add some extra life to the eyes, or when the features are very dark or when the shadows are too strong. I dial in my camera ( -3 stops ) flash setting. If that is still too much light, I place a thin white piece of paper tissue in front of the flash light to make it weaker.
Fill flash is a creative tool
In portraiture be it outdoors or in a studio it is important to understanding the principles and physical laws governing light. Chief amongst these is the inverse square law:
- The intensity of illumination of a
- subject due to the square of the
- distance between them."
What this means is that every time the distance between a light source and a subject is doubled, the light illuminating the subject drops by 4 times or 2 stops.
Example Fig 3 - There was one flash light to the left of the camera facing the subject , three feet from Noel's face. The background was a dark pattern grey colour 3 feet from Noel or 6 feet from the flash unit. Taking into account the inverse square law meant adding another small flash light behind Noel to illuminate the background with the same strength as the main light.
If the second light had not been added, then the background would come out very dark, creating inadequate separation.
Camera f/5.6, main light f/5.6 - by the time it reached the background the incident light meter read f/2.8 - 2 stops less.
For best results, photographing outdoors will require 1/2 to 1 full stop or more additional compensation. And subjects that are unusually dark or unusually light normally require 1/2 to 1 stop more, or less respectively.
