This format is used by Olympus cameras to create RAW images. These files record data from the camera matrix that are used to generate the image. It contains raw data about contrast, saturation, color temperature, as well as metadata. The exposure and white balance can be changed in an ORF image while maintaining the level of detail and quality of the photo.
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.