Convert bmp to x3f Online: bmp2x3f
You can use Tom's Editor to easily convert images from
Microsoft Windows bitmap .BMP to Sigma Camera RAW Picture File .X3F.
Tom's Editor is a free, online image manipulation and converter program.
Go to Tom's Editor
Format created by Microsoft for their Windows and OS/2 operating systems. Images can be compressed or not.
Sigma Camera RAW Picture File is an image format with extension X3F.