Highlight clipping

Light is captured as a linear data by the sensor. One of the downsides
of this is that at the extremes whites can be captured as "burnt out"
pure whites sometimes referred as " roll-off".

It is harder to capture highlights in digital photography than
in film. A valuable aid to know when you have reached this
critical tonal area is by using the highlight clipping warning
on your camera. You can then adjust your exposure levels
to capture the highlights without burning out the linear data.

HIGHLIGHT CLIPPING- exercise

Take a series of images in a scene with a variety of images in a contrast
lighting , note aperture/shutter speed settings and then take a series of
shots where the exposure levels are one stop over and one stop under
the optimum exposure level.

make notes on the difference of the highlighted appearance

• complete loss of visual information
• A visible break on the edge from nearly white to total white
• a colour contrast along a fringe bordering the clipped white highlight
• the colour saturation.

London 2013- HIGH CONTRAST

series of images taken with a contrast reflection
Variation of reads

SHUTTER SPEED SET AT 1/40S

shadow aperture f7
highlight aperture f20

I then took a series of images stopping up and down using
the wave view to see the change in the curve to judge
the reductions in the over exposed areas of the images.

@ f7.1 the first image shows the over exposed area
of the highlights and is marked as red in the
raw conversion.

After a series of stops from shutter speed of 1/40s the best
result was set at 1/80sec at f6.3

the highlight clip as been reduced to a small area and can
be recovered using the raw convert in photoshop.




the final screen shots shows exposure reducing all highlights
over exposed taking the f stop up to f8 and therefore speed
reduced to 1/60sec.
 This though makes the areas of shadow too dark.

I would choose the middle exposure of 1/80sec at
F6 and recover the highlight in raw conversion.

using raw converter I have recovered the over

exposure and also added a small element

of in fill light

processed image

processing

• recovery of high light over exposure in raw 
• converter PS.
• fill light addition in raw conversion
• colour balance to daylight
• contrast adjusting in PS
• level adjustment in PS
• small area of doge foreground
• small area of burn in background
• final tonal adjustment.

conclusion

based on the scene being made up of a wide variation

in exposure measure it was hard to get an average exposure

level that did not cause some areas highlight not being burn out

by using highlight recover in PS I was able to recover the 

the area of over exposure.

FLAT LIGHT

Series of images taken in shaded flat light, onto a limited
tonal palate.

the simple image had one area of shadow below the

light and many areas of highlight as the glass panels

reflected some of the light that was breaking through

the cloud cover.

TTL light reading for the area of shadow f 5.6

@ 1/60s

Area of highlight TTL reading f13 @ 1/60s

the above shows the over exposure at f 5.6 in

the area of highlight.

f8 1/60 sec

the next exposure setting was an average

between the two areas of shadows

 and highlights.

There are no ares of over exposure but the image

 is very flat as it has very limited tonal or

light variations.

exposure set f13 at 1/60s to set correct exposure 

for area of highlight.

unfortunately this shows the area of shadow too dark.

f7.1 @1/60 sec

As I was struggling with exposure as settings were

either too high or too dark. 

I checked exposure again and choose to shoot one

stop under average and would then recover the

high lights in PS

Below shows the recovered image in PS which
shows the removal of the highlight clippings
and also I chose to colour balance the image
to daylight which shows the change of the colour
tones from flat grey to bluer " white " light.

I then process the final image from this
recovered raw conversion

image processing information

• lasso around the light foreground 
• inverse selection
• level adjustment of back ground addition of more dark
• inverse selection level adjustment addition of white to
• light shaded area
• colour balance of image

conclusion

I have concluded that highlight are best manage by controlling
the initial exposure levels.

By taken a selection of exposures by setting under and over stops
you can see the change in the areas of over exposure and
can see the improvements in the high light clippings!

The reverse to controlling the highlights is that by recovering
the highlights mean you may loose details in the shadows.

A mid exposure on my shot was flat and the image
had no contrast so I chose to select a shot below that
to include some contrast.

Highlights can be recovered in PS so it may not be
appropriate to set the exposure for full highlights as
discussed before this may lead to the loss of the shadow
detail.