histogram

[jduncan]

lets see if i have this histogram malarkey..
the histogram has 5 vertical bars
an adequately exposed photo with a full range of tones will look like a nice neat hump sort of covering the middle three and maybe moving to the edges, correct so far??
too dark where shadow detail is lost and too light where highlights are lost will appear as sharp spikes at each their respective sides.
is this ok so far?

james

[martcol]

As a general rule James, I think you're right. However, it doesn't always follow that the ideal shot is humped in the middle. It depends what the shot is of.

If you have a picture that has bright white areas, you might correctly expose but there may still be a bias toward the right of the histogram and likewise, dark shadowy pics will bias to the left.

The Histogram is a graphical display of how the spread of pixels is in that particular image. They can give an immediate idea of what the photo is like. I find them useful in helping to evaluate pictures of the same shot especially, where I've bracketed i.e. taken shots a stop or less (or more) either side of what the camera recommends.

Martin

[Dans_D60]

The histogram on the 10D is theoretically calibrated to cover the full dynamic rage of camera. Each bar on the graph represents roughly one f-stop. So distribution from the darkest (left side) part of the image to the brightest (right side) of the image is five f-stops. Every shot will appear a little different. Nevertheless the histogram is helpful with showing an image that is dark (too many pixels on the left) or light (too many pixels on the right). The number of pixels is indicated by the height of the graph. Good shadow detail requires maximum dynamic range as indicated by a full distribution across the entire histogram. You may never see a “nice neat hump”, but good details are dominated by a midtones which is in the center of the histogram graph. With that said, there always exceptions to the rule! The attached image is my 10D (taken with my D60). As you can see from the histogram this image is almost absent of midtones yet it still achieves good dynamic range across the entire graph.
Dan
http://www.pettusphoto.com

EXAMPLE HISTOGRAM WITH LIMITED MIDTONE
http://www.pettusphoto.com/dslr/10d.jpg

[jduncan]

got it!

thanks for the help

james

[Ricciardi]

Well.

Yes and know.

If you take a picture of a back cat, your histogram would be mostly at the lelft side.

If you, on the other hand, shoot a white wall, the correct histogram would be at the right side.

And if you shoot a gray card or midtone scene, the histrogram would be in the center.

To judge the histogram you have to take in consideration what you're shooting.