Exercise: Histogram

Outline: Increase your familiarity with histograms by relating each one to the image you have shot. Take and image of a low contrast scene, one of a mid contrast scene and one of a high contrast scene and for each one, take another two images varying the exposure. Write a short note for each image and histogram combination explaining how they relate.

I will hold my hands up on this exercise and say I messed it up pretty much from the start. I had set my camera setting, unknowingly, to shoot RAW, but not with the jpeg image aswell and then due to a distraction I only took images of each contrast on the level exposure setting. Seeming as I have been confused about histograms up until now, I really wanted to get a good grip with this exercise and thought, due to my mistake, that I would be worse off. BUT....

I actually understand them now.

I tried to set up my canon 1000D to show the histogram at the time but for some reason, it wont actually show it (I'm also having the same trouble with the live LCD shooting!). I uploaded all the images to elements organizer and as I have shot them all in RAW, I have the exposure slider as well. So with a lot of fiddling about, not only can I see and record the effects by altering the exposure slider, I have also really understood the theory behind the histogram.

As for the exercise:

This image of a garden playhouse shows very low contrast. The values for this image, as shown in the histogram are all bunched up in the centre of the column graph. This confirms the lack of shadow and depth, creating a flat image.

The over exposed image shows how the bunched up values moves across to the right..... 

...and the underexposed image shows the values move across to the left. 

As there are no shadows or bright areas in these images, the shadow and highlight warnings have not shown here with any areas of concern.

The above image has a medium contrast. The shadow warning has picked up the dark areas between the leaves on the bushes, indicating the shadow as being the darkest level that the camera can manage, with it already showing as black and cannot appear to be any darker.

In the over exposed image, the histogram shows the values heading more to the right side of the graph (white). The highlight clipping (the red area) shows us that the colour has been lost here as the brightness level is too high for the camera to record any data, and the area will appear as white.

This street scene on a cloudy day has a high contrast, with areas of bright reflection and also some shadow. The histogram shows the values really spread out, right up to the edges of the graph on both sides. 

Highlight clipping has indicted a few small areas where the brightness is too high, but this can be amended by altering the exposure f-stop.

 The over exposed image shows that most of the light coloured surfaces have now been affected by the highlight clipping, showing any colour that was actually visible in these ares has now been completely burnt out and made to look white.

The underexposed image is the better of the three here. The histogram is a lot more leveled out and the highlight clipping has disappeared because now there is enough darkness in the image to show some colour. 












Conclusion:  I have a much better knowledge of histograms and shadow and highlight warnings from this exercise. The final image of this exercise shows exactly what the highlight clipping does and how it warns you that vital image detail can be lost due to incorrect exposure. And that the histogram is actually a great tool to have ( if it actually can be used on the camera) to assist in creating the ideal exposure at the time of shooting.