PDA

View Full Version : Histograms



Geoff Chandler
06-07-2005, 09:49 AM
Well - I have waited long enough and I still don't really know
Can anyone explain practically how you use a Histogram - to me it is a meaningless graph of spikes. I would guess one end is the shadow and the other the highlight - but still when I look at them they don't relay anything that tells me anything usefull.
Sorry to sound stupid - I'm not..Honest!!

Geoff :rolleyes:

Chucko
06-07-2005, 10:26 AM
For starters, histograms can serve as an indication of whether an image is correctly exposed. If the histogram appears to be "piled up" at one end of the graph or the other, chances are good that a different exposure would yield a better image. Of course this isn't terribly useful if the image is a silhouette, or otherwise deliberately over/underexposed for effect.

The histogram is most useful when you are going to print an image. Printers inherently offer less of a dynamic range than CRTs or LCDs, especially with low-cost papers, so you have to make the most of it. Dark shadows tend to "plug up" and highlights go white, losing detail in either case. So you want to stay away from the extremes and go for a range across the middle of the histogram as much as practical. Again, if the image in question doesn't need shadow or highlight detail, this may not matter.

For detailed explanations of what the histogram can tell you, I highly recommend the "Professional Photoshop" books by Dan Margulis. It seems Dan comes up with a new edition for each release of Photoshop, but the earlier editions are worth keeping and re-reading. I swear his books improved my photography at least as much as the $$$$ I spent on SLRs, lenses, and film.

g0tr00t
06-07-2005, 12:26 PM
Here is a LOAD of detail.

http://www.digitalsecrets.net/Sony/AdvancedKnow.html

aparmley
06-07-2005, 04:03 PM
I didn't check out the previous link but here is another on for you that sums it up rather nicely with photographic examples...
Histograms (http://www.pcworld.com/howto/article/0,aid,120600,00.asp)

Phill D
06-07-2005, 10:34 PM
Geoff that is a question that has been going round in my mind too. I felt exactly as you did & I'm sure a lot of people will get help from this thread. Thanks guys for the replies just enough information to convince me for one to have a go. It sounds like familiarity & practice are the key as always. I just hope the family don't get too frustrated with the extended time it will no doubt take to take photographs as I get used to histograms.

g0tr00t
06-08-2005, 06:10 AM
Phill D, you will be surprised once you get used to it how you ever survived without it before.

I shoot in M mode on my P&S and just go by the histogram. I have learned not to trust what you see on the LCD's since no two are the same.

Good luck in your venture you will enjoy it!

Fred
06-08-2005, 11:22 AM
I believe this site also has a good tutorial regarding histogram use:

www.luminous-landscape.com

It should be under the "Understanding series" button.

Savannah
06-08-2005, 08:26 PM
I believe this site also has a good tutorial regarding histogram use:

www.luminous-landscape.com

It should be under the "Understanding series" button.

Fred,
Thanks for reminding us about this web site.
I had the same question a few weeks ago and found this article to be very useful. The entire series is great, easy to understand and very applicable.

Fred
06-09-2005, 10:21 AM
You're welcome, Stacy. I agree that this site has some very useful information. When I'm stuck with something, I try to remember to go there to see if anything applies.

gary_hendricks
06-27-2005, 07:47 AM
Hi Geoff,

It's great that you asked - I've just written a short article (http://www.basic-digital-photography.com/how-to-use-the-camera-histogram.html) on how to interpret and use your digital camera's histogram. :)

Geoff Chandler
06-27-2005, 11:43 AM
Thanks Gary
I will try to get my head around that when I have a bit of peace and quiet.

John_Reed
06-27-2005, 03:55 PM
...which tells the shooter whether or not the histogram is clipping on the right side (bright side). If you see flashing highlights in the quick review (which I see instantly through my viewfinder), you know you've driven the histogram into the clipping region on the highlights, and depending upon whether the highlighted details are important to you, you'd better reduce exposure, and try again. Kind of a "short-cut" histogram? But I use it all the time, with good effect.