Monthly Archives: February 2012

Exercise: Histogram

For this exercise, I had to take three images of a low contrast, average contrast and a high contrast scene. I had to bracket the exposures so that there was one under exposed, one at average exposure and another over exposed. When viewing these in Photoshop, I had the shadow and highlight clipping turned on so that it was obvious on the histogram and I took a screen shot of each one.

For this exercise I’d been doing some reading around histograms to help me understand what they should look like. While I’ve used histograms before, reading around has helped me to realise what I should be aiming for when I’m taking images and viewing them on the back of the camera.

To help me I’ve put together a little chart based on what I’ve learnt as I’ve been reading

Underexposed

Average exposure

Over exposed

Shadows, graph to the left

Midtones, graph in the middle

Highlights, graph to the right

The closer the image is to the left or the right, the greater the chance of shadow or highlight clipping, although the information screen on my camera can highlight this so I’m aware of this when I’ve taken the image.

Low contrast image with under exposure

Low contrast image with average exposure

Low contrast image with over exposure

My low contrast image is of a bird against a dark background. As its low contrast and quite dark, I’d expect the histogram to be on the left hand side of the graph and to be highlighting the shadows.
For the under and average exposures, the histogram reflects the amount of dark tones and shadows and this is obvious with the shadow clipping in the underexposed image.
With the over exposed image, the tomes are much more balanced, not only is this reflected in the image but also the histogram. The histogram is much more spaced across with high peaks on the shadow side, stretching to low peaks on the left hand side and towards the highlights.

Average contrast image with under exposure

Average contrast image with average exposure

Average contrast image with over exposure

My average contrast image of the two pots has a more centre based histogram, with little variation between them. As it’s a more evenly spread histogram, it doesn’t have the shadow or highlights that are clipped, even on the over exposed image.

High contrast image with under exposure

High contrast image with average exposure

High contrast image with over exposure

 

My high contrast image is of a dark chair frame against a light cream background. With average exposure, there is no shadow or highlight clipping, however the histogram is quite widely spaced across with peaks towards the shadow and highlight zones.
The underexposed image changed as I’d expected with still some central peaks for the more average tones but a very strong peak towards the shadows, and it showed a small area of shadow clipping on the right hand side. My high contrast and over exposed image is the opposite to the under exposed image and there is a very clear trend of highlight clipping with a huge peak on that side of the graph. It’s also the one image out of the series where there are very obvious and large areas of blown highlights on the cream wall

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What inspires Annelies Strba?

Just googling for some of the images I saw at the Alice in Wonderland exhibition at the Tate gallery, specifically Annelies Strba, and I came across a few questions that were submitted to Annelies by local Liverpool children in conjunction with this exhibit.

Not only does it show the images I’ve referred to in my learning log, but its also an interesting quick overview of her work. I’m certainly going to look into her work a bit more as I find it fascinating that she can create these images through photography.

For anyone who wants a look

http://wondermind.tate.org.uk/i-wonder-what-inspires-annelies-strba/