I have been taking pictures now for nearly two years. I have read about the histogram that the camera produces and on how it can help you, but to be honest linear capture was not one of the first things that I had researched.
After reviewing my next project I took a little time to research this topic. Although when we take a picture the images that we see on the back of the camera seem to be what is in front of the
camera this is not really the case. Our eyes see lights in a different way to the way that light falls on the sensor of the camera. In view of this the camera takes the image, processing takes place and you see the image on the camera.
There is a great deal of difference between the two images and this can be seen on the histogram.
For this exercise I had to take an image and show the viewer what it would look like before the camera made the corrections. This is the Linear Image.
I went to Guildford for the day and took a number of images of people on the canal.
The image I chose had colour – a girls dress, white – the top of the boat and black – the water.
Here is the image that I could see.
This is the image that the camera would see before it starts processing, next to the above image
Here is the linear curve and the histogram for the above image (left side)
You can see that the image on the right is darker, (see the girls dress) and there is less detail in the water.
Following the instruction in the course work I again adjusted the gamma correction cure in an attempt to produce an image closer to what the human eye would see.
Here is my finished image, next to the one above.
Here is the linear curve and the histogram for the above image (right side)
You can see that the information depicted by the histogram is not bunched up to the left side of the scale but spread out along the scale giving a more pleasing image with greater detail which a photographer could work with.
I did find this a rather hard concept to explain. As I said I did look at a number of websites and other students blogs to see why they had done.
I did find an interesting website at http://www.covingtoninnovations.com/dslr/Curves.html. Here Michael A. Covington explains linear curves and capture.
Copyright 2004 Michael A. Covington.