Needs to be at least 16 0x00's. I get a CRW file that I can open and see an image.
Don't confuse the *extension* with the *format* of the file. If you have DNG turned on you get a DNG. Some programs are smart enough to figure out a file with a format that doesn't match the extension.
If you get a working DNG (the image isn't scrambled), your raw parameters are correct, and you can ignore everything below
Okay - worked out how to get the makefile in the tools directory to build an executable version of rawconvert. What should I use as command line parameters to get an 8bpp greyscale - that was not obvious and trial & error has not helped. Also - any suggestiong on what image viewer should understand the resulting output ?
Thank again!
http://chdk.wikia.com/wiki/CHDK_Toolsrawconvert -12to8 -w=<width> -h=<height> [-pgm] <infile> <outfile>
-12to8 says to convert a 12 bit per pixel to an 8 bit per pixel.
The non-pgm output of rawconvert is understood by many programs (gimp, irfanview
http://www.irfanview.com/ photoshop) that have an "open as raw" command where you can enter the bit depth and dimensions.
Most of those programs probably also understand pgm.
The width and height don't have to be correct, they just have to match (width*height*bpp)/8 == filesize. Use whatever values you have in camera.h. If you get them wrong it will be obvious in the image, and you can try different values in camera.h.
In irfanview, you would do
"open as raw", and enter 8bpp (greyscale, 1 byte per pixel), and the same width and height you used in camera.h