Nikon 25420 Digital Camera User Manual


 
Reduce exposure if you see clipping. Try to get the histogram as close to the right side as
possible without touching it.
If your scene looks too dark when you do this there is no correct exposure: the scene's
dynamic range (lighting ratio) is too great. In these cases professionals will correct the
lighting by adding fill light to the shadows and/ or using scrims to dim the highlights.
Amateurs scramble to attempt to increase the dynamic range of their cameras using hocus
pocus like my increasing dynamic range trick.
A little bit of clipping is OK on things like the highlights of sun dancing on water or the disk
of the sun. Clipping broad areas like someone's forehead looks awful and often shifts
colors. This is art and you'll have to learn what looks good to you. There is no law, so don't
worry about being scientifically correct.
Look closely and you'll see a peak on the left at 100% black, even when overexposed. This
is the dark shadow on the left of the photo. This shows that the camera's contrast needs to
be lowered, or better still, add fill light in the shadows. This is why you would see three
huge trucks full of electric generators and lighting equipment if this was a Hollywood movie
shoot. It takes a lot of artificial lighting to make a scene look natural on camera. Cameras
respond very differently than our eyes.
Usually an image is underexposed if no channel of the histogram goes all the way to the
right. Images that are too dark are easy to correct later; just drag the right slider in
Photoshop's Levels command to the left to meet the edge of the histogram.
Overexposed digital images are almost useless. Anything that washes out to white is gone
forever. There is no way to drag Photoshop's Level slider to the right of the right side
because there's no data out there beyond 255.
A2/9 How to Use Color Histograms
INTRODUCTION
I explain basics of histograms at How to Use Histograms (page 79). Read it first. This page
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