histogram question

Was reading a different post and thought about this question.....

On some shots, my histogram has a high center peak and balanced, but sharp declines to both sides -- leaving "blank" areas for about 1/3 on each end.

what causes that?

You can have that a lot. What you tried to take picture of has no bright or dark spot. For example, try to take picture of a mid-gray paper (nothing else),

THIS site may be helpful.

A histogram is a brutally honest representation of the tonal values of you picture.
The left side of the histogram represents black (a digital value of 0) and the right side represents white (a digital value of 255). The vertical component of the histogram represents how many pixels of each value from 0 to 255. So a very white scene like snow will have a big spike on the right of the histogram and a night scene will have a bit spike on the left of the histogram.

The histogram represents about 7 stops of dynamic range (but on a monitor you can only see about 4 to 5 stops)

If you see the histogram curve clipped on the left or right, you've lost detail in your photo. It can't be recovered. It's beyond the dynamic range of the camera.

You should always shoot average lit scenes where the bulk of the information is on the right of the histogram without it being clipped. Of course there are always exceptions to the rules. You just need to know how to interpret the information on the histogram. Sensors are optimized for more information on the right. If you try to brighten up a dark exposure in post production, you will create "noise" in the very dark areas of the photo. But it's ok to darken a bright photo (as long as the highlights are not clipped or blown out)

OK..... related histogram question, but an inside flash question as well....

I take pictures inside (house or gym) I use an EX580 flash set on program mode... I set my ISO, but the pictures are still heavy on the black side. I can usually edit the problem in Photoshop, but would rather fix the problem when I take the pic.... I have tried increasing the exposure setting but tend to get bright foreground and dark background. How do I adjust the settings?

drmac wrote in post #5295565
OK..... related histogram question, but an inside flash question as well....

I take pictures inside (house or gym) I use an EX580 flash set on program mode... I set my ISO, but the pictures are still heavy on the black side. I can usually edit the problem in Photoshop, but would rather fix the problem when I take the pic.... I have tried increasing the exposure setting but tend to get bright foreground and dark background. How do I adjust the settings?

Have a read here:
http://planetneil.com …s/3-dragging-the-shutter/
It could explain it way better than I ever could.