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10/04/2005 02:40:51 AM · #1 |
1. how to read a histogram on the camera, x-axis, y-axis?
2. how can it help during composition of shot
3. how can it help during post-processing in photoshop?
4. how did it help you make better photos?
Thanks |
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10/04/2005 02:56:42 AM · #2 |
1. how to read a histogram on the camera, x-axis, y-axis?
x-axis represents the range of tones from darkest black to the brightest white
y-axis represents relative number of pixels at that tone in the image.
2. how can it help during composition of shot
While the exposure settings indicate the average exposure of the scene or the exposure for a speciific subject (for average and spot metering respectively) the histogram shows the exposure of the entire scene at once. that is, at a glance it is possible to see where the lightest part of the scene is (and if that highlights are blown) and where the darkest part is (and if the shadows are blocked).
3. how can it help during post-processing in photoshop?
First and foremost it is an invaluable representation of how the tones of the image are distributed. Aside from that, it shows contrast (narrow hump having low contrast, wide hump having high contrast, amoung many other things.
4. how did it help you make better photos?
Like any graph, it gives a representation of the image that isn't always readily apparent from looking at it. That different view has as many uses as there are reasons to look at it.
David
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10/04/2005 03:16:53 AM · #3 |
| so a photo with a histogram shaped like a "U" wont be too good, right? I mean, it would be stretching the sensor's dynamic range a bit there. I'm just trying to understand, so do correct me if I'm wrong. thanks |
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10/04/2005 04:15:39 AM · #4 |
There is no right or wrong histogram -- it is just another way of looking at the image. However, an image with all the pixels divided between the extreme left and right would be black and white -- no (or at least very few) grey areas. Like this one, but perhaps not as extreme:
most detail is usually in the middle, with the extremes of light and dark reserved for the few highlights and shadows in the image -- but just becasue that is the norm doesn't make it always right. For instance, a high-key image will have the majority of the pixels on the right side of the histogram (the light side), while a low-key image will have the majority on the left (the dark side).
When I first started using it I could really only determine two divisions, light and dark; later I added a recognition of the midtones and later still more divisions of grey between the light and dark extremes. The point is, the more you look at the histogram, the more you learn to see what it can tell you -- but don't worry about not being able to see everything at once.
David
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10/04/2005 04:18:46 AM · #5 |
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10/04/2005 08:34:54 AM · #6 |
Chris,
Good article, thanks for posting.
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10/04/2005 09:37:09 PM · #7 |
good article Chris, i find it informative.
I'll keep the histogram on for now onwards. might learn some new tricks with it ;) |
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