Digital
Exposure...
If you are used to using print film in a 35mm camera
and have just switched to digital you may not be happy with some of your
results... One of the main reasons for this is because of the exposure
latitude of print film compared to digital, and the way you need to meter
for digital... Using a digital camera is like shooting with slide film
in the respect that the image is a first generation image and needs more
accurate exposure... With print film you can over expose an image by 1
stop which will saturate the colours and if you over do it slightly the
printing machine will most likely compensate for any errors... With digital
images and slide film over exposure can kill an image because it will
burn out the highlights and once this is done you can never get them back...
It is always better to expose correctly with digital, but if you have
to compensate, compensate with slight under exposure as this will at least
have some detail that you may be able to recover in Photoshop or other
digital software... Below are variations of the same image in 1 stop increments
of exposure from plus four stops (over exposed) down to minus four stops
(under exposure)... You will notice that at two stops over the helmet
badge is blown out and that detail can never be recovered whereas at two
stops under, though dark, the badge details can be retrieved... At four
stops over the face is completely lost and practically void of detail
while at four stops under exposed, though really dark some image can actually
be retrieved with digital software...

  As you will see from the image on the left the attempt to bring detail back into the image which was four stops over exposed has failed miserably... None of the colours are true to the correctly exposed image because of the lack of information in that image... With the use of the fill bucket you might be able to improve it slightly but it would never be of a quality that would be of any use...
Now believe it or not the image on the right has been recovered from the image which was four stops under exposed, yes, the one that nearly looks all black... All the details that were in the correctly exposed image have been recovered... Granted the image is more grainy and the colours not exactly true to the original but this image could still be used... So remember err on the under exposure side if you are not quite sure of what to do...
In extreme contrast situations you must decide which part of the image is most important to you, and expose for that, because the latitude of digital exposures are very limited...
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