Exercise : Your Cameras Dynamic Range

Your Cameras Dynamic Range


Both highlight clipping and and noise are digital problems, they are at opposite ends of the tonal scale.  They define what is known as the dynamic range of the camera.  The easiest ways of measuring it is in the form of f-stops.

The dynamic range is the number of stops between the brightest highlight and the darkest shadows.  The cameras range is less than that of a scene - something has to be lost.  This is the cause of most of your exposure problems.  Highlight clippings are one end of the scale and are therefore easier to find, and noise determines the other - this is not always as easy to find.  There is a point at which it is impossible to distinguish between noise and real detail.  To find this you need to lighten the image in photoshop temporarily to see.


Ths scene below is of high dynamic range.
Bright sunlight.
At least one reflective surface.
An area of deep shadow with a dark surface.
A3 white card as highlight.

The ISO is set to low and set the exposure to the white card with no clipping.

The white card here measures 50cm x 70cm  ( Img 6902 )  1/1000   f8

I've opened the image in photoshop and checked the RGB values, they were all to 255.  
Then I moved to shadows and adjusted the brightness until the details were visible.  This was
+3.60 exposure.

I would say my Dynamic Range was about 8 or 9, however I have printed details from the internet which all vary and say 10 or more.

Items researched on Internet.