The Historgram

[Texas Sadie]

I took a college class in Photoshop, but the instructor didn't cover the historgram. I hear it refered to a lot in this forum. Exactly what is it for and how do you use it?

[OversighT]

The histogram depicts, graphically, the amount of pixels in varying shades from black to white in your photo and helps you determine if you've properly exposed the photo. On the left of the histogram are the dark pixels and on the right are the light pixels. The height of each line represents the number of pixels of that shade. So, if you see a lot of tall lines on the left hand side of the histogram you've probably underexposed the shot. Conversely a lot of tall lines on the right means you've probably overexposed the shot.

Hope that helps.


T.

[Texas Sadie]

Thanks. Can it be edited to give a better exposure?

[Bill Huber]

I use the histogram a lot, but you do have to watch it that you don't make it a bible to live by. It is just another tool to use and that is it.

That a look at this site and see if it will help.

http://www.luminous-landscape.com/tu...stograms.shtml

[OversighT]

Originally Posted by Texas Sadie

Thanks. Can it be edited to give a better exposure?

Not directly, but you can use it to know when you have a shot that needs a bit of exposure correction. You could either use the histogram in the camera and reshoot or use it in PS and edit the photo on your computer.

And like Bill said it's just another tool in your belt. Just because the histogram indicates that you've overexposed a shot doesn't mean it needs to be reshot...you may have been going for that look all along.


T.

[markperez]

Originally Posted by Texas Sadie

I took a college class in Photoshop, but the instructor didn't cover the historgram. I hear it refered to a lot in this forum. Exactly what is it for and how do you use it?

How did he/she show you how to do levels without talking about the histogram?

[bburton]

Originally Posted by Texas Sadie

Thanks. Can it be edited to give a better exposure?

Sadie,

Your camera, the Canon PowerShot Pro1, has a histogram which can be turned on when reviewing a shot immediately after taking it.

If you don't like what the histogram shows, adjust camera settings and take the picture again. This feature is not quite as useful as a "Live Histogram" which appears in the viewfinder or on the LCD screen, before taking a shot, but is yet another tool to use to get exposure right before post processing.

[Justin]

Originally Posted by markperez

How did he/she show you how to do levels without talking about the histogram?

I was also wondering how anybody could teach a class on Photoshop and never mention a histogram, seems like quite a big omission. If you haven't used "levels" in Photoshop yet, check it out. Very handy for playing with exposure if you're like me, and don't always get it right :)

[Junomech]

Here's an excellent link to Histograms. I've been researching these for a week now. This is by far the best explanation I've seen about Histograms.

http://www.digicamhelp.com/what-is-a-histogram/index.htm

[johnastovall]

Originally Posted by Texas Sadie

I took a college class in Photoshop, but the instructor didn't cover the historgram. I hear it refered to a lot in this forum. Exactly what is it for and how do you use it?

Here's a good tutorial on understanding histograms in digital photography.

http://www.luminous-landscape.com/tu...stograms.shtml