I found a scene which demonstrated a wide range of brightness. There were a few clouds in the sky, some bright areas on the floor and on the statue. I set my camera on a tripod and took a series of images to work out the setting at which highlight clipping began to occur.
1/750 F4 ISO100 24mm
Working through a sequence of decreasing the shutter speed and keeping the aperture the same (F4) allowed more light to strike the sensor thus overexposing the image.
During this exercise, I was hoping to find:
- completely lost areas of visual information
- a visible break in the form of an edge between nearly white and total white
- a colour cast along a fringe bordering the clipped white highlight
- colour saturation
My images demonstrated them all.
Image 1
This was my first image which I thought was OK when I checked the histogram and highlights displayed in the back of the camera. My camera displays highlight clipping as overexposed areas flashing on the display on the back of the camera. This image had no highlights displayed in camera. On closer inspection using a RAW processing programme, I discovered that the highlight on the black post was actually blown out. The area is very small and the loss of detail does not appear to affect the image.
1/500 F4 ISO100 24mm
Image 2
This image was taken one stop darker (shutter speed faster so less light reaching the sensor). There appeared to be no areas of highlight clipping on the display in my camera.
1/750 F4 ISO100 24mm
Highlight clipping is visible on the black post (the same as in image 1) when viewed at 100%, even though the image looks to be correctly exposed. The colours on this image are more saturated and I think are more acceptable.
Image 3
This image was taken on a slightly slower shutter speed than the first image. By taking the image in RAW and displaying the highlight clipping in the processing software, the highlight clipping is shown as an area of red. The book has become clipped, and there are very small areas on the posts on the left hand side, right hand side and along the back wall of posts, a spot on the statues’ foot and a couple on the floor.
1/350 F4 ISO100 24mm
The highlights on the floor are beginning to lose detail. When I looked at the book in detail at 200%, I could see where the areas of burnout would occur. There is a break which appears as an edge between white and nearly white.
Image 4
1/250 F4 ISO100 24mm
The camera speed has been slowed further, letting more light reach the sensor. This image shows much more highlight clipping mainly on the book and floor. There is more visible too on the posts.
Image 5
This image is really blown out. All of the floor is marked red, so too is the book and the clouds are now visibly blown out. The statue which was fairly dark to start with now shows highlight clipping.
1/180 F4 ISO100 24mm
By slowing the camera speed even further, the colour saturation of the whole image has now become weak (desaturated). Highlight clipping is visible behind the trees in the cloud and most of the floor is overexposed. This area is unrecoverable. There is evidence of a colour cast along a fringe bordering the clipped white highlight where the fence post shadow and floor meet, which shows as a red line.
For the final part of this exercise, I looked at recovering an image using RAW processing software. I took the most overexposed image (image 5) and by using the recovery slider, I was able to move the colours on the histogram back towards the left. This restored my colours back to somewhere between the first and second image. I was able to adjust the brightness and contrast which helped restore the colours and by moving the tint slider, I could influence the red or green colours. I still think the image would look better if it was exposed correctly in the first place.
