Novice Raw vs JPEG question, Type I

[Wayne]

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I now have my camera, and have a day to play around with it.

 

I have been recording DNG-JPEG so far. It is the first instance I have had of greatly preferring the out of camera Raw image to the JPEG. Is the JPEG image nothing more than a compressed version of the Raw image?

[hoppyman]

Hi Wayne. The JPG is compressed with loss of a lot of information and typically has changes to the colour, contrast etc to a standard meant to be appealing.

The DNG contains effectively all of the information that the camera recorded and so has much more scope to be manipulated in processing. For example recovering information barely visible in highlights or darks, altering the White Balance etc. Once the camera or your image processing program has made a JPG version of your raw file, you can't get back all of the discarded information. That may or may not matter depending on what you want the images for of course.

When you view a DNG on the camera LCD you are actually seeing a preview generated from the raw information. If you are importing into Lightroom for example, then you initially see the low resolution preview that is embedded in the raw file. Then a new preview is generated (up to 1:1) with similar adjustments as with the camera generated JPG. Typically that preview can look 'flatter' that is to say it won't have had the same compression of tonal range). However you can endlessly change that conversion with no loss of any original information (until you output a version in another format of course).