in all cases, we work from black (no light) to white (all channels saturated), those possible values get mapped on a certain range (using 8, 12, 16 bits). So currently, most cameras are able to encode up to (2^12)^3 or 68 719 476 736 values/colours. That said, none here ever disputed that 8 bits/channel was enough for display.Ĭamera data are stored in 12 or 14 bits, and the value of using 14 bits is I think still being discussed (not only a question of camera construction, but also of physics imposing hard limits, aka noise). I think there's a slight misunderstanding: taking the alpha channel into account does NOT increase the number of colours you can encode (note: colours, not values): alpha channel adds transparency, so you'll mix the colour in one layer with whatever is underneath, and the result must be expressed in 8 or 16 bit without alpha channel (sooner or later). I'm not quite sure what the name of this number is, but it is quite large enough for anything. For a photographer this gives you 281,474,976,710,656 or more than 281 trillion possible colors (assuming there are any cameras that can capture true 16 bit color). If you are talking 16 bit per channel you have 65,536 values per channel. And if you're colour blind like me, it could drive you stir crazy! (or not, if most of them all look the same anyway!) I personally don't know how many color values a camera is able to capture, but I don't think that it comes even close to the possible values 16 bit color is able to store. If you add the alpha channel this number rises to 4,294,967,296 or over 4 billion colors. Now most of you are probably aware of this, but using the three channels which cameras can capture this gives you 16,777,216 or over 16.5 million possible unique colors. 8 bits gives you 256 possible values for each channel. As only three of the possible four channels are useful for photography I will discuss only the R,G, and B channels. Some other manufacturers beside Panasonic, such as Sony, also embed lens correction profiles in their RAW files these days, so having Affinity support embedded profiles would probably be a very useful improvement and would lessen the dependence on the Lensfun library.Just out of curiosity I decided to do some calculations about 8 bit vs 16 bit, and what I discovered surprised me.Ī standard 8 bit image stores 8 bits for each of the either three or four channels. I've found a page that details this metadata and how it is most likely used by the programs that can use it: In my testing of Affinity Photo's processing of these files, I have found that choosing the "Panasonic Lumix DMC-FZ45 and compatibles" profile manually, as suggested by some for mostly any Lumix FZ model does not yield a satisfactory result, with very visible distortion remaining whichever way I tweak the correction, and doing a completely manual correction also leaves a lot of visible distortion that doesn't seem to be possible to accurately compensate for without using the specific correction data embedded in the RW2 file EXIF metadata. The only programs I have found that are able to use this information is Adobe Lightroom (and related Adobe products like ACR) and SilkyPix, both of which do not seem to have any pre-made profiles for this camera but rather uses the parameters from the lens correction metadata to create a correction on the fly (Adobe Lightroom in particular specifically tells me this when doing lens correction on the file). The RW2 files produced by this and many other Panasonic cameras contain a built-in lens correction profile for fixing distortion and chromatic aberration. I have found that Affinity Photo, both stable (1.8.5) and current beta (1.9.0), can not process RW2 files from Panasonic Lumix DMC-FZ80/82 with lens correction.
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