A Basic Outline and Guide to Understanding and Using 'Camera RAW'
Clive R. Haynes FRPS
Coping with an Incorrectly Exposed Image
Please note image sizes are fairly large to preserve detail, download times may therefore be slow.
From time to time things go wrong and the exposure is not what we would have wished.
Fortunately Camera RAW can recover an amount of 'lost detail', whether under-exposed or over-exposed.
The example below deals with an amount of over-exposure and the same basic principals may be applied for an underexposed scene.
Examining the Histogram for the image above we can readily see that the RH side of the Histogram - the 'white / max exposure end is running off the edge of the scale. If this was a JPEG or TIFF image then nothing could be done to rescue the missing detail. RAW files allows around six 'f-stops' of exposure recovery.
Working on the image above, the Exposure and Shadows 'sliders' have been adjusted to recover the 'lost' - overexposed detail. The 'Exposure has been set to 4 'stops' under-expose. The whole image will become darker by 4 'stops' but as you can see the detail in the bridge has been improved.
In the case illustrated above, the procedure would be to optimise the general exposure and any other 'corrections' for the scene using the RAW dialogue box and 'save' as a .PSD file, then re-open the original RAW file and make the exposure adjustment shown. Click 'OK' to open the adjusted (darker) image.
two images would then be combined in Photoshop by 'copying' and 'pasting' with
the' improved (darker) image' to a layer above the overexposed original.
Above: The results of combining the overexposed original RAW image with the 'improved' (underexposed) / adjusted RAW image. The quality of the recovered detail is quite amazing.
|To adjust for an underexposed image, the above procedure may adopted but this time lightening the dark areas of the picture.|
Do experiment to discover how much latitude you camera allows in RAW.
Next we'll look at how we can Reveal the 'Highlights' (White) and 'Shadows' (Black) 'Clipping Points'
- click the 'Continue' link below.