essential skills: digital photography in available light
Brightness range
Light is refl ected unevenly off surfaces, light tones refl ecting more light than dark tones. Each
subject framed by the photographer will include a range of tones. The broader the range of tones
the greater the contrast.
When harsh directional light such as sunlight strikes a subject the overall contrast of the scene
increases. The tones facing the light source continue to refl ect high percentages of the increased
level of illumination whilst the shadows may refl ect little extra. The overall contrast of the framed
subject is called the SBR or ‘subject brightness range’.
The SBR can be measured by taking a meter reading of the lightest and darkest tones. If the
lightest tone reads f16 @ 1/125 second and the darkest tone reads f4 @ 1/125 second the
difference is four stops or 16:1.
SBR of approximately fi ve stops (32:1)High SBR in flat lightExtreme SBR in harsh directional lightMidtones HighlightsIncreased exposure to capture shadow detailDecreased exposure to capture highlight detailLatitude of digital images
(JPEG & TIFF file format)Latitude of digital images
(DSLR camera RAW format)Shadow tonesA subject with a high or extreme brightness range can exceed the latitude of the image sensorSBR of approximately three stops (8:1)