Histogram

[Scrappinmamacita]

Are there any sites out there that explain the histogram, what it should look like when properly exposed etc,etc? I am just learning digital photography and am familiar with it but would really like to understand so I can properly correct my pictures.

[mgbeach]

heres a pretty good link, with more links from there
http://www.livingroom.org.au/photolog/tips/histogram_tips.php

What you'll find is that there is no such thing as one histogram that indicates correct exposure. The "correct" histogram will vary by subject and the effect you're going for. The histogram is a tool to indicate if you have captured the range of tones you need to end up with the final product you want. Good luck, and have a great day!

[Tonky]

Are there any sites out there that explain the histogram, what it should look like when properly exposed etc,etc? I am just learning digital photography and am familiar with it but would really like to understand so I can properly correct my pictures.

A Google search should throw up loads I would think, and the Help file in your processing application will probably explain it.

It's relatively easy though, a histogram from a well-exposed shot typically has the shape of a mountain with the peak or hump in the centre. tapering down to the base on either side without climbing the sides of the graph window on the left - which indicates under-exposure, on on the right which indicates over-exposure. That's a bit of a simplification but it's the nub of it. The shape of the graph may vary quite a bit but you need to avoid it being too far to left or right.

It's a very useful feature to be able to check the histogram in the camera after each shot, and take another shot giving more or less exposure as required.

[Scottes]

It's relatively easy though, a histogram from a well-exposed shot...
I can't agree with this statement. There is no way that the histogram itself will tell you if an image is well exposed. It always depends on the scene, too. A properly-exposed night shot, for example, is going to have a LOT of blacks and darks, almost nothing in the middle, and a small point on the right showing the bright lights in the scene. The histogram from such a shot will look nothing like "a mountain with the peak or hump in the centre." Yet the shot can be properly exposed. Conversely a shot of a sheep in a field covered with snow should show a histogram that's really bunched up on the right. Again, the shot will be properly exposed, but the histogram will look nothing like a lump in the middle.

You have to interpret the histogram along with the scene. This can be omplicated and difficult to get used to. In fact I almost never do this - I just check the histogram to make sure that I don't have any data all the way to the right, which would indicate some overexposure and blow-outs.

[etaf]

http://www.google.co.uk/search?hl=en&q=camera+histogram&meta=

i like the luminous-landscape explanation - included in first page of above search

[Harry Settle]

Luminous landscape, shootsmarter.com. Just for a couple of starters.

[Tonky]

I can't agree with this statement. .............

You have to interpret the histogram along with the scene. This can be omplicated and difficult to get used to. In fact I almost never do this - I just check the histogram to make sure that I don't have any data all the way to the right, which would indicate some overexposure and blow-outs.

Which is pretty well what everyone does, use the histogram to avoid over-exposure, so why complicate the issue, particularly for someone trying to get to grips with histograms, by referring to considerations you ignore yourself, even in the extremes of exposure circumstances you gave? ;)

[Scottes]

...so why complicate the issue...
Mis-information is much more complicating than extreme examples.

[robertwgross]

With a really typical daylight scene, a histogram often looks like a mountain that is centered on the histogram. However, there are so many variations on scenes that this is only a starting point.

Sometimes it is better to describe what a bad histogram looks like, and then just try to avoid those. If the histogram shows one big spike at the far left edge, and nothing else, then that is likely to be a very underexposed image. Similarly, if it shows one big spike at the far right edge, and nothing else, then that is likely to be a very overexposed image.

I was teaching a class one time, and I showed one typical scene, and then I offered choices of histograms, and the students were supposed to guess which was the correct histogram. At first, a few had troubles with it, but they get it after some practice. Then, later on during practice, you can look at the scene and almost predict what your histogram should look like. When the histogram pops up after the shot, you can verify that it is sort of the way you thought it would be.

---Bob Gross---

[J Rabin]

Are there any sites out there that explain the histogram...

Steve Hoffmann is one of the best:
http://www.sphoto.com/techinfo/histograms/histograms.htm

No such thing as good or bad, they just "are." They reflect the tonal range in an image.
Jack