Question 16

Raw files always contain uncompressed image data

ANSWER (B) Score 1 The answer is (B), false! In fact, most cameras use compression to keep down the size of their raw files and, sometimes, to make them faster to capture. Raw file compression comes in two forms: ‘Compressed’ and ‘Lossless Compressed’. ‘Compressed’ raw files use ‘lossy’ compression, like JPEGs, but less aggressive, so it’s unlikely any quality loss would be apparent, or even detectable. ‘Lossless Compressed’ raw files are like compressed TIFF images – no significant information is discarded and the compression process is simply stripping out redundant data. Only more professionally-orientated cameras offer true, uncompressed raw files, and these are significantly larger. On the Nikon D810 a Compressed raw file takes up 36.3MB, a Lossless Compressed raw file takes up 40.7MB and an Uncompressed raw file is a huge 73.2MB.