Need to read raw images for my project. I found lots of open source packages on line, but it still needs many efforts to read and incorporate the code. Then I remember that TIFF has 16 bit version, maybe I could convert raw to 16bit tiff, which could still give me enough information about the scene, since normally raw images have 12 or 14 bits for each pixel. This sounds convenient and effortless. However, after a few experiments, I found that 16 bit tiff still loses lots of information about the scene. Mainly because when you convert raw to tiff, you have to do demosaicing, white balancing, sharpening and gamma correction for viewing (maybe). This process will inevitably truncate some head room gained by using raw format when comparing with jpeg. That is why people says “stay in Lightroom for as long as you can” (or the equivalent “do as much in ACR as you can)”), as all edits in Lightroom are nondestructive and non-cumulative.

For a detailed investigation, please check out these posts,
http://forums.adobe.com/message/2742439
http://www.bobatkins.com/photography/digital/raw.html
http://www.cambridgeincolour.com/tutorials/RAW-file-format.htm
http://osp.wikidot.com/raw