If you are using XP, here is a replacement viewer (from MS) that handles Canon/Nikon Raw files, this should also allow the explporer thumnail display to handle them.
I also use a tool called ExifPro which is not an editor but a viewer that is super fast even for folders with hundreds of raw images. it supprts pretty much all Raw formats and also handles all the embedded info within the image including manufacturer specific data.
The best software I have found for initially tweaking the raw images is the Canon software, either the EOS Tools, Zoom Browser or Digital Photo Professional. These have the same processing and setting controls as the camera itself so you can adjust white balance, color tone etc which is something Photoshop cannot do, or cannot do exatly the same as the camera would of done.
Remeber no versions of photoshop support High Dynamic Range images, your raw files are stored as 36 bits per pixel, 12 bits for each of RGB and all three components are allowed to go above 1.0. Photo shop only supports 24 bits (8 bits per component) in the range 0.0 to 1.0. The photoshop raw dialog that appears when you load a raw file is the only place where the HDR data properly handled. Once you have passed that dialog and gone to the main photoshop window you are back to 24bit and you lost a lot of precision. This matters for things like exposure adjustments. For example, you have a raw picture of the sun, if you half the exposure in the RAW tools the sun is still white but if you do the same operation in photoshop after leaving the initial raw dialog the sun will be mid gray. Basically in the original HDR data you might have a white pixel within the image of the sun with a value of 2.0, photoshop cannot handle numbers outside 0.0 to 1.0 so it will clamp anything above 1.0 to 1.0 which still appears white so initially all is good. Now is you reduce the brightness to 50% the photoshop pixel is 1.0/2 which is 0.5 or midgray but the original pixel would be 2.0/2 which is 1.0 so is still white.
This has been a problem for years in movies and video games where the lighting data is true light values and your source data can have a massive dynamic range, especially if the sun is in the scene. We use a load of clunky tools to deal with the HDR data without destroying it, I can give you more details if you desire to enter a world of pain. Ww have asked Adobe many times for full HDR support but they keep saying it would require a complete rewrite of the Photoshop and it would break all the plugins. Maybe one day.
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