20 Flash techniques with the D-1 and SB-28DX

The combination of the D-1 and SB-28DX has introduced many new users into the field of flash photography with digital cameras. As some of the characteristics of the digital camera - in particular the sensitivity of the CCD (exposure latitude) and flash control system - are fundamentally different from its' film counterpart, the D-1 user should be prepared to revisit or even learn new techniques to fully master use of the SB-28DX flash in every situation.

When to Use Flash

It may be surprising to discover in just how many situations a speedlight proves useful. For instance as many photographers know well, taking pictures outside in bright sunlight will result in a wide tonal range between areas in shadow (such as the contours of the face) and areas exposed to the full sun (a forehead or hand, perhaps). The resulting exposure without flash will appear harsh and the wide tonal range of the image will be hard to print. By adding flash, using some of the techniques below, an evenly exposed picture may be achieved which retains the feeling of the ambient lighting whilst creating a balanced and manageable illumination of the subject.

Creating a Balance between ambient light and the flash.

Although the eye can accommodate wide ranges of highlight and shadow, digital camera's sensor is not so forgiving and help must be given in conditions where the ambient light conditions cast string shadows. Such situations may for example be where the sun, overhead spotlights, daylight from a window etc forms the predominant source of light and this light falls on the subject from one direction only. Is is not only the resulting large obvious shadows that may be troublesome but also the small shadows, particularly in portrait work, that may cause over-emphasis the of lines and distort features. Of course being able to position a reflector close to the subject is an excellent mechanical means of evening out the illumination, but when working solo, or in situations where the subject is not under the control of the photographer, such methods are impractical. In these cases, setting the SB-28DX to D-TTL Balanced fill flash mode is suggested. In this mode, the camera measures both the available light falling on the subject (taking into account the focus distance) and also that of the surrounding (background) area of the image, and then adjusts the flash and exposure so that the flash just "fills-in" the foreground.

Note that in certain circumstances the system may produce unexpected results and, due to the decreased latitude of an electronic sensor compared to film, under or over exposed images may occasionally occur. We hope that this document may help you to anticipate the circumstances where such conditions exist and to employ other techniques and settings that may prove to be more effective:
An example of the conditions where care should be employed include:

If the background is either very dark (shooting a subject in a large, empty room for example) or very light and reflective (for example, an ice hockey match, or with glass in the background), then the complex automatic measurement and control system required to produce Balanced Fill-flash may sometimes result in an under or over exposure.

It has been commented that the high frame rate and extended image capacity of digital (i.e. filmless) cameras has encouraged photographers to shoot far more freely than they used to with film. If the camera is being used in Continuous Mode at a high frame rate the power drain on the batteries in the flash system may become too great to support the sustained highly critical measurement that Balanced Fill-flash requires. In this case one shot out of a sequence may be affected as the equipment attempts to cope with falling flash battery voltage and high current demand.

When using a wider field of view (for example lenses with focal lengths of less than 35mm) beware of dominant light sources or sinks (dark regions which will not reflect light) which may affect the flash calculation and overall exposure even though apparently not in shot.

In compositions where the subject occupies a small part of the frame compared to the overall field of view.

In summary, then Balanced Fill-flash is a highly sophisticated combined operation where the camera and flash work together to evenly illuminate the scene. Fill flash works in all exposure modes and is compatible with normal, and front curtain sync

Dominating the subject with light from the flash to reduce the effect of mixed lighting.

One of the factors that digital photography has introduced is the issue of white balance. This is known to film photographers by the need to match the film type with the light (daylight film, tungsten film) or to add filters to eliminate the green cast of fluorescent light. Digital cameras are able to automatically or manually compensate for the colour imbalance caused by different light sources and accommodate many types of lighting. However, there are limitations to the range of compensation, and one major consideration is when different light sources are present. For example, reflected light from walls or a strongly coloured floor, daylight from a window or strong overhead lighting would all have a different colour temperature and could cause different colour casts for example on the different faces within a group shot, or even across the face of a solo portrait.. In these conditions, it may be desirable to reduce the effect of the ambient light and dominate the scene with the light from the speedlight.

Alternatively if it is required that the subject should stand out strongly from the background, set the SB-28DX to D-TTL, rather than D-TTL with fill-flash. In this mode, the camera expects that the flash will produce most of the light and that the subject should be clearly illuminated. Before the main flash fires, pre-flashes are emitted from the SB-28DX that are reflected from the grey shutter curtain in the camera onto the TTL flash sensor that measures the light in centreweight mode. When the shutter curtain lifts, the flash fires with a power output based on the pre-flash measurement. This produces an illumination where the subject will be predominantly lit by the flash, and the effect of ambient lighting will be reduced. Users of Nikon Film cameras will notice a subtle difference between these exposures and the D-1, as in the case of the D-1 the flash is not subsequently controlled during the exposure by measurement off the film surface itself. This extra degree of control (off-film measurement) is not possible with digital cameras as the sensor is not as reflective as film. This factor, combined with the decreased latitude of the sensor when compared to film means that the D-1 user must expect slightly less accuracy when using D-TTL modes, compared to traditional TTL mode of a film camera.

D-TTL mode is useful for macro work and interiors - when flash is the dominant light source - and may be employed for creative effects. for example outdoors at night when doing a portait shot where balanced fill-flash mode would be not be appropriate.

Note that the Monitor pre-flash measurement system is also employed in the D-TLL Fill-flash mode. In both of these modes, wireless triggering of secondary slave flashes cannot be used, as the monitor pre-flash would trigger the slave prematurely.

Bounce Flash

When the flash is mounted on the camera and the head is pointed directly at the subject, the resulting shadow may be visually objectionable particularly if the subject-to-background distance is small. Tilting the head up to reflect light from the ceiling will result in a much softer illumination as light source becomes much broader. However, although this may produce a desirable result, note that the light falling on the subject will be coloured by the surfaces from which it reflects and this may introduce a colour cast. As the colour temperature of the scene will be determined by the various surfaces in the room, great care must be take with white balance. Turning the camera by a few degrees may bring another surface into play which could influence the colour of the scene. The camera has many white balance control options: Selected (and "tweakable" with the front command dial), Auto and Preset, all of which are available to the photographer to find the most workable solution in each particular situation.

Note that in when using tilting the head, the TTL measurement system accuracy is reduced and superior results may be obtained with the flash must be set to A-mode. In this case, the traditional methods of setting the exposure using the guide scale on the rear of the flash should be used .

Focusing attention on the foreground in bright ambient conditions

There are certain circumstances where it may be required to throw the background out of focus using a wide-open aperture, but a high level of ambient lighting makes the use of flash almost redundant. In this case a special setting called FP mode allows for narrow depth of field shooting giving more options for flash photography in bright ambient lighting.

Setting the flash to FP mode will cause the flash not to fire once, but many times at an extremely rapid rate which in a conventional film camera beings with the opening of front curtain and ends with closing of rear curtain. This permits the correct exposure to be obtained as the traveling slit of a dual curtain shutter passes over the film at high speed. Although the digital camera does not employ a dual curtain shutter blade, (as the sensor is turned off electronically) this mode remains useable in the same manner as with film cameras. Set the camera to Manual exposure mode and raise the shutter speed to greater that the normal 1/500th sync speed. In this case, the flash power (guide number) may be simply and effectively controlled by rotating the rear command dial and changing shutter speed. The correct flash power is then set by matching the flash distance to the distance measurement on the lens.Note: Max shutter speed is 1/8,000 in FP mode with D1.
Note: Max shutter speed is 1/8,000 in FP mode with D1.
In Conclusion

The combination of SB-28DX and D-1 provides the photographer with a number of new possibilities and challenges. Techniques learnt from film may be adapted and expanded as the user learns both the benefits of the new technology and the precautions that must be observed with a sometimes less forgiving medium. Nikon staff worldwide have pooled their expertise to contribute to this page and continue to give support in the form of advice and training. We hope that this information has helped you to get more from your equipment in your pursuit of photography, whether it be for business or pleasure.

Footnotes:

1. The significance of Lens choice

The use of Nikon D-type lenses is recommended as the distance information from the lens is used to determine the subject/background flash ratio if the subject is not located in the centre of the frame. When using a non-D lens with balanced fill flash, the flash power calculation is based on the a centre-weighted metering pattern.

2. Exposure compensation on camera in flash

Care should be taken when manually compensating EV on the camera body and the flash manually as both of those effects are cumulative.