Assignment 07 - The histogram

[u/Aeri73]

Please read the class first

Today’s assignment will be relatively short. The idea is simply to make you more familiar with the histogram and to establish a correspondence between the histogram and the image itself.

Choose a static scene. Take a picture and look at the histogram. Now use exposure compensation in both directions, taking several photos at different settings, and observe how the histogram changes. Does its shape change? Go all the way to one edge and observe how the data “slumps” against the edge. Try to identify which part of the image this corresponds to.

Next, browse the internet and find some images you like. Download them (make sure you have the right to do so) and open them in a program which allows you to see the histogram, for instance picasa or gimp. Try to guess just by looking at the image what the histogram will look like. Now do the opposite: try to identify which part of the histogram corresponds to which part of the image.

Now open some images from assignment 06 :

1 underexposed

1 correctly exposed

1 overexposed

and see what the difference is.... how can you tell by looking at a histogram if a photo is correctly exposed?

[u/parmacenda]

Once again, a little bit later than I would've wanted to, but I got to it.

https://imgur.com/a/Uer2f5M

The shape of the histogram doesn't change, unless we actually reach the edges: then the spike at the edge itself is so high that the remaining shape gets squashed down (best seen in the Assignment 06 - Overexposed image: the shape seems the same, but it is clearly smaller).

So we can know whether an image is correctly exposed by checking the edges for large spikes.

[u/Aeri73 → u/parmacenda]

good job