DIGITAL EXPOSURE...
f 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... 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...
t 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...
To the left 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...
To the left 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...
I check the histogram in tricky situations and make sure the graph is over to the right, but not bunched that way... The graph should just touch the right bottom edge of the histogram then I know the highlights will not be blown... The above images show I could always pull some detail out of the shadows in Photoshop...
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...
I check the histogram in tricky situations and make sure the graph is over to the right, but not bunched that way... The graph should just touch the right bottom edge of the histogram then I know the highlights will not be blown... The above images show I could always pull some detail out of the shadows in Photoshop...
