Tuesday, 10 January 2012

Exercise 3: Histogram

The aim of this exercise is to increase familiarity with the histogram by looking at the histogram of images you have taken.

Histograms can be viewed in camera after an image has been taken and also in image processing software.

If you shoot in raw the histogram is taken from a jpeg and not the raw file itself so you may see some changes when it is opened in Photoshop.

Low contrast

Low contrast average exposure shot

The histogram shows that the bulk of pixels are in the midrange of the brightness scale

 One stop under-exposed

The graph has moved to the left as there are more darks in this image


One stop over-exposed

The values have moved to the right as the image contains brighter pixels. It is also overexposed. 

Average contrast

Average exposure

The histogram shows a wide range of values across the scale

One stop under-exposed

The values have shifted to the left as there are more darker pixels in the shot. There is also an increase of white pixels. 

One stop over-exposed

There is still an increase is white pixels with the whites being out of the camera's dynamic range and a big shift from blacks on the left. 

High Contrast

Average exposure

The histogram shows a wide range of pixels across the scale with the majority of values in the left and right.

One stop underexposed

There are no white values with a big rise in the left as the image is underexposed. 

One stop over-exposed

There is a shift to the right with very few values in blacks. 


The histogram gives you an indication of whether the image you are shooting is within the camera's dynamic range and over or under exposed.  As there is no correct exposure for a shot you may wish to have your image underexposed - if you want blacks to be black or overexposed if you want white snow to be white.  Checking the histogram can help you achieve this.  


















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