This is a format that is used to store RAW photos on Sony digital cameras without the use of compression. It contains the complete set of information that was captured by the camera's sensors through the lens when shooting with minimum adjustments. The opportunities for post-editing depend on the camera model and lens. ARW files can be created and edited in the ArtStudio Image software.
BMP is format for storing bitmap images. In this format, you can only save bitmaps monolayer. For each pixel in different files may come different number of bits. The latest versions of the BMP has the ability to control color. In particular, you can specify the endpoints perform gamma correction and embed color profiles ICC.