Gossen DIGISKY - Handbuch (Seite 31)

GOSSEN Foto- und Lichtmesstechnik GmbH 31
9 Practical Notes
Programming DIGISKY to compensate for external influences affecting exposure
The DIGISKY provides you with precise exposure data in accordance with DIN 19010.
In the unlikely event that you are not satisfied with your results, it is possible that one or
more external factors may have adversely influenced the final exposure. Some possible
factors are:

The
“Actual” film speed may differ.
 Your camera’s “actual” shutter speeds may deviate somewhat from the nominal
values.
 Your camera’s “actual” f-stops may differ from those specified.

Deviations may occur while developing negatives and prints.
Any or all of these factors may be further compounded by subjective factors and
personal taste when evaluating finished pictures.
Fortunately, you can
adapt the DIGISKY to your camera’s individual characteristics,
your workflow and your own subjective evaluation criteria.
We recommend the following method - Carefully measure several standard objects
(grey card, grey scale and colour charts are perfect for this purpose) in reflected light
and incident light modes, and complete a series of exposures. Use the value given by
your DIGISKY. The first image is made with the exposure value displayed by the
DIGISKY. Then, this exposure value is increased or reduced by up to one f-stop,
dependant on the increments/
“stops” of the lens. Lighting conditions must remain
unchanged during this test series. From all developed or printed photos, select the
image which is the best one in your opinion and compare its settings with the
measurements. If the image has a different value (i.e. +/- one f-stop, etc.) compared to
the original meter reading, you can set the corresponding value into your DIGISKY with
the help of the Correction Value Mode (see page 26).
Contrast and Best Exposure
Basic rules for the best possible exposure dictate that the brightest and darkest parts of
the image should have adequate detail. Yet, individual opinion and personal
creativeness may, of course, render these rules null and void. Thus only general
recommendations regarding the subject of ideal exposure can be provided.
It is important to consider the fact that the final product (photo, print etc.) is only capable
of processing a small contrast range compared to the human eye. By means of the
DIGISKY, you can measure the lighting contrast in the incident light measurement
mode, as well as the subject contrast in the reflected light measurement mode. In both
cases, the contrast is shown in the analog display. In general, you do not get the correct
exposure for your subject by measuring the brightest and the darkest points. This
should be either a medium grey within the subject, or the average value of the
measurement results for the brightest and darkest points. The average value is
calculated automatically by the DIGISKY. If you find that the subject contrast range is
bigger than your workflow is capable of processing, you can brighten up shadows, for
example, by using a reflector or a employing a fill-in flash, consequently reducing the
subject contrast.
When subject contrast is taken into consideration by means of generating an average
value, the following general rules apply: