Exercise : Highlight clipping.

 Outline: Using a scene with plenty of contrast and an auto setting with exposure adjustment, make a series of photographs, adjusting the exposure setting to alter the area of highlight clipping.


I took my series of photos in the garden on a cloudy afternoon. The sky being overcast with white clouds would prove a decent experiment for the highlight clipping exercise. I searched the menu of my camera but unfortunately my camera does not have a highlight clipping warning, so I shot the images anyway in RAW and then used the highlight clipping warning in photoshop to complete the exercise as best I could.

I set the camera to auto setting where I could adjust the exposure and the aperture was set to F5 and the shutter speed was set to 1/30. I used the auto ISO setting.

The first image without adjusting the exposure:

Even by looking at this image here, we can see that the sky in the image is completely white. The garage roof and the childrens play house are both white also, but here we can see a distinction between each of these details and the whiteness of the sky. There is a definite outline to where these subjects end and where the clouds begin. With the highlight clipping visible:

We can see the sky is completely highlighted with it being washed out. There is even warning on the top level of the childrens slide. The sky has no different levels of colour at all, it purely shows that all colour and visible information has been lost. The garage roof has also lost information but here we have a break that can be seen between where the colour has been lost and the actual white colour of the guttering.

By increasing the exposure by 1 fstop, we can lose even more information.

I notice by this image that the visible break between the garage roof / play house and the sky has pretty much disappeared. The shed roof still has some colour but this is also a lot whiter than in the previous image. This is worth mentioning as a visible break between white and nearly white.

The highlight clipping warning emphasizes these issues, showing more colour being washed out on the garage and play house. The slide is almost all washed out here and we have even lost information in some of the plants. The shed roof still has colour showing there is still a visible break between it and the sky.

However, just by decreasing the original image by 1 fstop we can see a huge difference.

The sky in this image does not appear to be white anymore, more of an 'off white' colour. There is a grey colour cast along the roof of the garage, showing a shadow and therefore, extra detail to differentiate between the garage roof white and the cloud in the sky. There seems to be a lot more detail through shadows in this image however, the colour saturation still shows no detailing through the sky. But then if we were to amend the image as a whole to highlight the detailing in the clouds, I am sure detail through other areas would be compromised.

With the highlight clipping warning on, we see that there are no areas of lost information in this image.

Going back to the original image and using the recovery tool, I moved the slider to the right and noticed a significant change with the recovery at '20'.

Here, we see that almost all the information has now been restored to the sky and we only have slight clipping warnings along the edges of the subjects against the sky. By the time the slider reached '26', all the highlight clipping warnings had disappeared.

I did experiment with the slider but after slider got to '26' (above), there was no change to the image at all no matter how far to the left I moved the slider.

Conclusion: This was a very interesting and necessary exercise to explore the highlight clipping facility and after all the evidence shown through using the highlight clipping warning in photoshop, I'm slightly disappointed that my camera does not have this facility built in. However, looking at the images above, I much prefer the image where the exposure was decreased by 1 fstop compared to the 'recovered' original image. I feel there is more detail available in that image and with more shadows it gives the image more of a 'cloudy/overcast' feel to it.