Friend of mine an avid user of Nikon system ask me the question about 4/3 and m4/3 sensor specification. While I can answer some of it, it's a bit difficult to answer specific things like RAW compression bits, pixel density and so on. He also ask the question about why many picture example in four-third.org have a bit loss of gradation in highlight part. I know that Olympus use 12-bit RAW compression but how about Panasonic what kind of raw compression did they use? Also I have read in other forum that m4/3 tough use smaller sensor size have more pixel density compared to some APS (entry level) sensor. They even have some sort formula to count the pixel density? Anyone can clarify this?