Go Back   Steve's Digicams Forums > Digicam Help > Newbie Help

Reply
 
Thread Tools Search this Thread
Old Dec 22, 2004, 3:12 PM   #1
Junior Member
 
Join Date: Nov 2004
Posts: 3
Default

Hi all,

I was wondering if anyone could tell me why you would need to look at this info on your photos. I have the option of viewing this in playback mode on my FinePix s5100 but I'm not sure why I would need it.

Any direction would be greatly appreciated.

Ebony
quiltingyrl is offline   Reply With Quote
Sponsored Links
Old Dec 22, 2004, 3:56 PM   #2
Senior Member
 
Join Date: Oct 2002
Posts: 544
Default

A histogram is simply a distribution of pixels in various ranges... with number of dark (under exposed) on the left and light (over exposed) on the right. Ideally, you'd see a distribution over the whole range. The histogram is a great tool to improve your exposure settings. I check the histogram on each shot and will often adjust settings and re-shoot to correct the exposure.


Wildman is offline   Reply With Quote
Old Dec 22, 2004, 11:07 PM   #3
Senior Member
 
Join Date: Dec 2002
Posts: 5,803
Default

You might find this link helpful:
http://www.luminous-landscape.com/tu...stograms.shtml

Eric
eric s is offline   Reply With Quote
Old Dec 23, 2004, 1:07 AM   #4
Senior Member
 
minutephotos.com's Avatar
 
Join Date: Jul 2004
Posts: 344
Default

I have used that same link to understand histograms. Some say a histogram is an adequate replacement to a light meter. I use them both, I use a light meter to set up my studio lights or to mesure ambient light outside. I glance at the histogram after each shot to see if my exposure is as expected. Many time I have used my light meter to set aperture, but fogot to set the ISO to match the meter reading. The Histogram saved me instantly.
minutephotos.com is offline   Reply With Quote
Old Dec 23, 2004, 8:20 AM   #5
Junior Member
 
Join Date: Nov 2004
Posts: 3
Default

Thanks for the explanation and the link.

Ebony
quiltingyrl is offline   Reply With Quote
Old Dec 23, 2004, 10:22 AM   #6
Senior Member
 
Join Date: Nov 2004
Posts: 935
Default

I think that a 3D histogram would be nice...a plot of X, Y for the pixel position, and Z for intensity or whatever.
Kenny_Leong is offline   Reply With Quote
Old Dec 23, 2004, 12:39 PM   #7
Senior Member
 
Join Date: Oct 2004
Posts: 838
Default

Kenny_Leong wrote:
Quote:
I think that a 3D histogram would be nice...a plot of X, Y for the pixel position, and Z for intensity or whatever.
What you describe isn't really a histogram (3D or not). What you describe is the actual intensity of the pixels at each position. A histogram, on the other hand, groups intensities and plots their frequency (position is irrelevant). For example, if the left-most bar in a histogram is high, it does NOT mean that the left side of the pic has high intensity; instead, it means that there are a lot of pixels (could be anywhere in the picture) at the lowest intensity grouping (say, 0 to 1).
Sivaram Velauthapillai is offline   Reply With Quote
Old Dec 27, 2004, 10:07 PM   #8
Senior Member
 
Join Date: Nov 2004
Posts: 935
Default

true true...you're right. I was thinking of a 3D plot, with X and Y positions and intensity for Z axis.
Kenny_Leong is offline   Reply With Quote
Old Dec 28, 2004, 7:59 AM   #9
Senior Member
 
BillDrew's Avatar
 
Join Date: Jun 2002
Location: Hay River Township, WI
Posts: 2,512
Default

Kenny_Leong wrote:
Quote:
true true...you're right. I was thinking of a 3D plot, with X and Y positions and intensity for Z axis.
That is a fair description of a b/w image.

Some digicams "flash" the blown out areas when previewing/reviewing.
BillDrew is offline   Reply With Quote
Old Dec 28, 2004, 9:18 AM   #10
Senior Member
 
Join Date: Nov 2004
Posts: 935
Default

Very true..it's like a grey-scale image, except it's plotted to show the level of intensities using lines. Just a contour plot thing.
Kenny_Leong is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 2:06 AM.