View Full Version : interpretting the graphs

31-01-2011, 12:11pm
when reviewing photos through the lcd screen, if you hit the info buttton (canon) there are 3 graphs that pop up, one in blue, red and green, also another graph. can someone tell me how to interpret these graphs, and what exactly i should be looking for.

31-01-2011, 12:15pm
what you are looking at there are called histrograms (just look that up on wikipedia) but what they are basically showing you is how the particular colour channel is spread from underexposure (left side) through to overexposure (right side)

They are quite important to understand as it they can really help you understand how you are exposing and capturing all the colours and tonal range of any particular scene.

31-01-2011, 1:52pm
ok so i wikipedia'd histogram, and it didnt really help much, but i found this page on it at http://www.cambridgeincolour.com/tutorials/histograms1.htm, it is a very comprehensive explanation, and ive learned a lot, so for anyone else asking what exactly those graphs are, check it out.

02-02-2011, 9:55am
Thanks heaps for that link bxaftw. I'm brand spankin new to all of this and I've often wondered the same. That is a really helpful link! :D

04-02-2011, 7:55am
There is loads of infomation a lot of it very technical on histograms.
Dont get too coaught up in the technicsal bits. Basically, you want a big pile in the middle and a little bit at each end.
But... dont be afraid to push it off to each end if the subject warrants it, (night, snow).

04-02-2011, 7:56am
This is probably the easiest tutorial on histograms for beginners, it lets them get their heads around the concept very well : http://www.luminous-landscape.com/tutorials/understanding-series/understanding-histograms.shtml

05-02-2011, 11:24pm
Thanks for the reference to the article on histograms Rick.

I found it very interesting and comforting in a way.

As i read the begining, the author used some words such as dynamic range and histogram and this led me to believe that the author would define them and relate it to using the camera, but this did not happen. These are concepts which i have used and taught for about 25years now, but not related to cameras. I also wondered about his first image using a cpl filter with the sun so strongly on the right side of the photo.

The author's explanation of Dynamic range makes the whole article a bit confusing and their attempt to relate it to more practical matters made me wonder how it related to taking photographs. Could i suggest that anyone reading this starts from the second sentance of 'The histogram'. Afterall that is the heading of the article.

I am not being negative about this article because I read through the whole article and the experience of the photographer shines through beautifully. His commment that the histogram 'simply shows the way things are' and that he demonstrates some nice photos with skewed histograms to the right and to the left shows that the histogram does not tell you if the photo is good or bad and that maybe? he is not acting on the histogram given the emphasis he places on it in the first part of the article.
In fact in his 'examples' section, he has turned his attention to the image details as his way of analysing the image and then relating the histogram to what he 'sees'.
Therefore his analysis in this section goes agaist his argument about the importance of histograms.
I could keep making editorial comments but I will say the following

The photographer's experience in taking photos certainly shines through and I wish I could develop his talent for image.
His consideration of what you want to get out of a photo in terms of exposure is certainly worth considering. 'Hi key', 18% greyscale or other exposures are all valid methods.

I think the biggest message for a beginer is to look at your photo and see if the image gives you a pleasing feeling. If not, then consider the histogram, composition etc as tools to imporove your image. I wish i could!:rolleyes: