Digital devices boast of the claim that WYSIWYG, i.e. What you see is what you get. But, in practice, it is rarely true. Why is it so that ‘What You See is What You DON’T Get’? The answer lies in understanding the concept of Dynamic Range.
Dynamic range is the ability of a device (camera, scanner, human eye) to capture both shadow and highlight details in high contrast scene. A device may capture a contrast ratio of 1024:1, it is said to be having a dynamic range of 10 stops. (1024 = 2 raised to the power of 10). A cloudy day typically has a dynamic range of about 3 stops, while a bright sunny day has a dynamic range of over 12.
The human eye can perceive a greater dynamic range, than that is ordinarily possible with a camera. The instant dynamic range of human eye is about 12 stops. However, if we account for the pupil adjusting to the different light intensities, the dynamic range of eye is well over 24 stops! The dynamic range of most compact digital cameras is around 5 to 6, while that of digital SLR cameras is about 9 to 10 stops.
This explains… why what we see is what we DON’T get!
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