I recently bought a Canon EOS300D. Usually I use my Nikon F4 with full range of lenses loaded with K64 / Provia or Velvia. I decided to spend 2 weeks shooting digital with the EOS300D only (with good lens -> 17-40 F4). I shot nearly 820 pictures in 12 days. All the pictures in Raw format with the exception of some (roughly 20) in jpeg. At home, I browse the RAW pictures and noticed some of them are underexposed or overexposed. I then use the RAW utility (called FileViewer for Canon) for altering the exposures. Results are quite incredible, even with exposure correction of 2 stops.
Here follows a personnal explanation (I am an engineer -> technical). In raw format, for the Canon EOS300D, the pixels are recorded in a 12 bits resolution. Converting to 8 bits drops 4 bits. The 4 bits that are dropped corresponds to 4 stops (log in base 2). This deduction seems correct since the Canon RAW utility allows to alter the exposure with a range of +- 2 stops (-> 4 stops). Therefore, there is a huge advantage keeping the files in RAW format that allows 12 stops of exposure range. The aforementioned explanation is just personal deduction from what I experienced practically with the EOS300D raw format and from my personnal professional knowledge (computer science engineer). Apparently, the exposure measured with the camera is centered on the 6 bits of the sensor resolution.
The RAW Truth: Does it really increase the dynamic range?
in The Digital Darkroom: Process, Technique & Printing
Posted
I recently bought a Canon EOS300D. Usually I use my Nikon F4 with full range of lenses loaded with K64 / Provia or Velvia. I decided to spend 2 weeks shooting digital with the EOS300D only (with good lens -> 17-40 F4). I shot nearly 820 pictures in 12 days. All the pictures in Raw format with the exception of some (roughly 20) in jpeg. At home, I browse the RAW pictures and noticed some of them are underexposed or overexposed. I then use the RAW utility (called FileViewer for Canon) for altering the exposures. Results are quite incredible, even with exposure correction of 2 stops.
Here follows a personnal explanation (I am an engineer -> technical). In raw format, for the Canon EOS300D, the pixels are recorded in a 12 bits resolution. Converting to 8 bits drops 4 bits. The 4 bits that are dropped corresponds to 4 stops (log in base 2). This deduction seems correct since the Canon RAW utility allows to alter the exposure with a range of +- 2 stops (-> 4 stops). Therefore, there is a huge advantage keeping the files in RAW format that allows 12 stops of exposure range. The aforementioned explanation is just personal deduction from what I experienced practically with the EOS300D raw format and from my personnal professional knowledge (computer science engineer). Apparently, the exposure measured with the camera is centered on the 6 bits of the sensor resolution.
_michel moreaux