GUIDE TO SHOOTING RAW PART V

EXPOSURE CONTROL

AUTO SETTINGS ON OPEN

When a raw file is viewed either in an organizer such as Adobe Bridge or opened into raw conversion software, the proqram mates a decision as to how it looks By default most programs will apply auto tone settings You may notice that as the preview image fully loads, it changes - which is the effect of the auto modes being applied You can also select defaults depending on the ISO or camera used By switching these auto modes off, your files are likely to look flatter and may require more editing time, but it also gives you more control Should you wish to add the auto setting later, there are auto tone buttons just abo/e the Exposure slider in both Lightroom and Adobe Camera Raw (ACR)

USING HISTOGRAM IN RAW - CLIPPING WARNINGS

The histogram in your raw conversion software is perhaps the most useful tool you have, as it can guide you to edit the exposure of an image On a basic level it shows if the image is over or underexposed and whether there is room to boost the levels For fine adjustment it can help 'you maximise the highlights and shadows to produce a full range of tones and even spot colour casts As the histogram shows data for the red, green and blue channels separately, a dominance of one colour should show a different tone curve from the others, which can then be adjusted for The histogram can also be set to display clipping warnings on the image In Adobe Lightroom or ACR, by clicking on the triangles m the top comers, the highlight and shadow warnings are activated Now. when the image is adjusted, clipped shadow areas appear as blue and highlights appear as red This is a useful way of seeing exactly where in your image you are starting to lose tonal information, before then making a decision as to whether to keep it in.

EXPOSURE SLIDER

The exposure slider works much like the exposure compensation on your camera and its measurements are given in EV The result of moving the slider is essentially like that of a signal boost or gain control, and it affects the tones in the image equally Most software will provide a range of ±4EV on the slider, althouqh taken to these extremes it is likely to result in a reduction in quality, especially at +4EV.
When making exposure adjustments to your image, this is the first slider you should use, as it sets your hstogram into
roughly the right position before making finer adjustments lower down the list By holding down tlie Alt key and adjusting this slider, the main image will show in colour only the areas that are overexposed, so adjusting in this way until only black shows is a great method of ensuring that none of the image data is lost.

RECOVERY, FILL LIGHT AND BLACKS

The Recovery, Fill Light and Blacks sliders in ACR and Lightroom work in partnership to adjust different tonal ranges in the image The Recovery slider works on the highlights and, by increasing its value, the brighter tones Mil be reduced This is used to bring detail back into the image for areas that appear to be dipped on the histogram

Using the highlight clipping on the histogram or holding Alt on the keyboard while adjusting this slider allows you to see clearly when all the burnt-out highlights have returned Severely bright sections that cannot be rescued may appear to be recovered, but will not have any detail in this area If this is the case, it is best to leave these parts slightly dipped Visually, the Fill Light slider can have the greatest effect on an image By increasing the value of the fill light, the darker tones are lightened to reveal more detail without losing any highlights in the process However, areas that were too dark to register may appear to be brought back but not show any more detail, and m this case noise or a mosaic pattern can start to show and the slider is best reduced slightly to leave these parts in shadow The Blacks slider performs almost as a direct opposite to the Fill Light slider on the darker tones By increasing the slider the tones become even darter, stretching the histogram left without dulling any of the highlights As with the Recover/ slider, the effects can be viewed using the shadow dipping warning on the histogram or by holding the Alt key while adjusting This will then show in colour only those areas that are too dark.

TONE CURVE ADJUSTMENT

The Tone Curve adjustment will be familiar to Photoshop users and allows the tonal range to be adjusted n a line graph form An even weighting of tones has a straight line from bottom left to top right, with the tones going from blade to white from left to right along the bottom. For a more contrasting image, an S-curve shape is formed by clicking and dragging on the line. 

The tone curve in Lightroom and the full Photoshop version of ACR offer a wide range of adjustment methods for curve control.

The first of these is direct adjustment of the line 5y clicking and dragging on different points The three slider controls underneath the graph divide it into four sections - Shadows, Darks, Lights and Highlights - and adjusting these sliders determines the range of each of the sections to be adjusted.

The sliders represent the four sections of the graph and as each is adjusted the line on the graph reshapes This also helps to teach photographers how the tone curve works A dropdown box allows the curve to be set via a senes of presets, including Strong Contrast and Linear.

ACR Curves control
The full Photoshop version of the ACR control pallet performs all but the direct on-image adjustment of lightroom

 The final adjustment method, available only in Lightroom, is the de/erest and perhaps the most useful By clicking on the small symbol to the top left of the graph, you can dick and drag directly onto your image to adjust the tones in that section This means you can dick on a skin tone and drag the mouse upwards to lighten, then dick on the backgound and drag down to darken.

 

 

PRESETS (LIGHTROOM)

Lightroom offers a wide range of presets in each of its sections Within the Develop section some of these relate to the exposure and contrast, including Punch and Medium Contrast tone curve Users can also create their own presets, by making adjustments to an image and then selecting the plus symbol on the preset list and ticking a I the required adjustments fa inclusion in the preset This can then be used on other images with a single click

SYNCING EXPOSURES

In a similar way to applying a preset, most raw software allows you to repl cate the adjustments that are made to one image to multiple images using Copy and Paste, or the Synchronise command Once the changes are made to your first image, any adjustment, including the exposure settings, can be copied to all the other files selected This is handy when working with images taken under consistent lighting, such as studio work