Exercise: Highlight Clipping

Part 1 – Find a scene which has a wide range of brightness – appears contrasty, in other words.  Using either manual exposure or, if your camera has the facility, exposure adjustment with an auto setting, find the exposure setting at which the highlight clipping warning just appears.  Make a note of the aperture and shutter speed.  Next, increase the exposure for a second shot by one f-stop, adjusting either the aperture or the shutter speed.  This will show a wider area of highlight clipping.  Then take three more shots in which you decrease the exposure each time by one f-stop.  You should then have five frames, each separated by one f-stop.

When I moved over to my new camera last year, I hunted high and low for the ability to show highlight clipping in my LCD screen, but couldn’t find what I was looking for and pretty much forgot about this function as at the time I never really used it anyway.  Over these past months, as we have discussed histograms, colour channels and now highlight clipping, I turned to my trusty manual to see if I could work out how to include this information against my shot data – hooray, I have found it, along with some other funky little displays that I am now able to use to assist me with my exposure control … so, on with the exercise ahead.

We have been having some bad weather – in photography terms – these past few days, cloudy overcast skies and high winds, which has proved difficult in finding a scene to shoot for this exercise.  With this in mind, I decided to try and an old favorite, in the hope that I would be able to get the conditions I was looking for to do this exercise.  I headed to the viewing platform outside of my apartment and set about taking my five photographs, but I really struggled to get the effect I was looking for.  I had been planning on using an indoor set up for the next exercise in this module, but as I was not getting anywhere with my results, I decided to use my miniature studio (which I have not used before) to set up a still life for this exercise.

Borrowing an idea from a colleague, I set the scene using a black velvet backdrop, to soak up any residual light, and a white base, to break up the black.  I used a diffused light source on the right of the image and an undiffused light source, placed a good distance away from the object in the left of the image.  My ‘model’ was a mug, teabag and teaspoon, which was placed so that it poked out of the top of the mug; I though this and the teabag would introduce different elements to the frame.

Using my Nikon D800 set on manual mode, I dialed in the widest aperture I could muster, which turned out to be F5.3, and governed my exposure by changing shutter speed.  After playing around with distance, lighting and clipping effects, I set my focal length to 105mm and used a tripod, as I did not want to change the scene in any way or introduce camera shake to my images.

The first image was taken so that the highlights were ‘just clipped’.

1/3 With Clipping

1/3 With Clipping

 

1/3 Without Clipping

1/3 Without Clipping

There is nothing unusual or unexpected about this image.  The light source to the right of the mug is closer to the subject, so the light has picked up all of the raised areas of detail.  At this point the detail is not completely lost, but it is not until you get in very close that you can see the pattern, there is a visible break between the nearly white and white area, identified by the rectangle on the following image, in fact there is a yellowish cast through the mug outlining this.

1/3 Showing Clipped Detail

1/3 Showing Clipped Detail

In the next image, the shutter speed has been decreased by one-stop to 0.5.

0.5 With Clipping

0.5 With Clipping

0.5 Without Clipping

0.5 Without Clipping

A much greater area of the image has now been clipped and the red area has engulfed not only the teabag but also the whole right side of the mug, as well as the area where the light source hits the floor of the miniature studio.  Again, this is not an unexpected result; with the shutter being open that little bit longer, the light has been able to flood the sensor that much more.  A magnified view of this can be seen in the following image.

0.5 Showing Clipped Detail

0.5 Showing Clipped Detail

We have received the same results as with the previous image, but things are much more exaggerated now and we can see that there are a couple of areas where detail has been completely lost to the light.

These next three photos represent a recovery of the brightness.  When I shot these images, the results I saw in my camera’s LCD did not show any clipping present, but when I opened the RAW images in Photoshop it was a different story.

Speeding up the shutter now, in the next photo the exposure has been reduced by one stop from the original image, and two from the last image.

1/5 With Clipping

1/5 With Clipping

1/3 Without Clipping

1/3 Without Clipping

There is a definite reduction in the clipping and the tones are really beginning to recover in this image.  There is still an area of highlights behind the teabag, but now you can make out the pattern in the porcelain.  The detail in the teabag has recovered and the area to the left of the image is beginning to darken, showing more detail here too.

A further reduction in exposure sees a massive difference in the look of the next image, which was shot with a shutter speed of 1/8.

1/8 With Clipping

1/8 With Clipping

1/8 Without Clipping

1/8 Without Clipping

There is only a small amount of brightness in the shot now, and this is mainly due to the deep pattern in the mug.  The detail to the left of the mug is beginning to blend with the background, making the two undistinguishable. The distinction between nearly white and white is almost balanced and the visible edge between the two has almost disappeared.  Now we can see colour saturation in the left of the shot and it is vastly improving in the right of the frame.

The final image was taken with a shutter speed of 1/13 and equates to 3-stops under exposed from the original image.

1/13 With Clipping

1/13 With Clipping

1/13 Without Clipping

1/13 Without Clipping

This is obviously the darkest of the five images as it has the shortest shutter speed and the least amount of light within the frame.  The detail has completely returned now and in fact in some areas the tables have turned and the black is being lost in the background due to there not being enough light to highlight the highpoints on the mug.  There is still some evidence of brightness behind the teabag, but it is not so white that you cannot see the detail and the colour saturation is good, in fact the balance in this area is almost perfect as you can even distinguish what the pattern is in the porcelain.

Conclusion:

Of the five images taken, my preference is the one taken with a shutter speed at 1/8, as I feel that this shot holds the most information and balance within the frame.  The colour saturation is not bad, and although there are a couple of areas that are still very white, I do not think this would change, even at slower shutter speeds than dictated by the exercise as this is due to the nature of the subject and the way the lighting is set.

1/8 Without Clipping

1/8 Without Clipping

From this batch of images, the one thing I would change if I shot them again would be my aperture; I set it wide so that I could bring as much light into the frame as possible and to increase my shutter speeds, but as I used spot metering the focus is concentrated on the light areas, so the darker areas to the left are slightly out of focus, which is okay for the pattern, but it would have been nice to see the drum (the coloured splodge in the middle of the cup) in better focus.

Another lesson learnt here is never to trust your LCD screen completely as the information displayed is not the same as the information recorded by the sensor, this comes down to the fact that our cameras produce a compressed JPEG image for use to view at the time of shooting and our RAW files contain uncompressed information – which we looked at during the exercises we did on linear capture.

Part 2 – if you shot the images in RAW, now go back to process them a second time.  Most RAW converters now offer a slider called Recovery or something similar.  This works in a special way, making use of the fact that the three channels (RGB) do not clip at the same time.  So, even though one channel may be clipped, or even two, the Recovery control uses the available information to ‘re-build’ the clipped channel.  Experiment with this slider at different strengths, and note the effect.  Very strong use may introduce some strange, unrealistic effects.

Find the best compromise position according to your judgment, and save a copy of the image using this.  Note the results in your learning log.

For this part of the exercise I used my original image shot with a shutter speed of 1/3.  I was not able to find the recovery slider in Photoshop, but I do know that it is available in Adobe Bridge, so I used this function to recover my shot.

For a comparison, here are the before and after shots of the image details.

Original Image Information

Original Image Information

 

Changed Image Information

Changed Image Information

This was a really interesting exercise to complete as to get the image looking right I had to play around with most of the sliders in this dialog box.  At first I had to crank the recovery slider all the way to 100, but once I started moving everything around, I was able to decrease this to finish at 91.  In the end, I used every slider available – just to see what the result would be, which I have included below.

Recovered Image

Recovered Image

There is a really funky, almost 3D feel about the image now as most of the lines have blurred edges, especially those in the area of the original clipping.  The one thing I was not able to get right was the colouring in the drum on the mug, but I like the way the troughs and grooves are more defined, and I have been able to maintain some of the brightness behind the teabag, as this is really the focal point of the shot.

What this exercise has really shown me is how easy it is to manipulate digital images so that we can get the results we want to see over those that are a true representation of the original subject.  This is something I have always known, and one of the reasons I have avoided Photoshop in the past, as it is just too easy to play around with things and change reality for fantasy …

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