CR2 is Canon's in-camera RAW
CR2 is the raw sensor data a Canon camera writes at the moment of capture. It's produced by the camera's own hardware and firmware — software can read it, but nothing can manufacture a genuine CR2 from a finished FITS.
Looking to turn a FITS into a CR2 file? Here's the honest answer — and what actually works instead.
You can't convert FITS to CR2. CR2 is a camera's own RAW format — it only ever comes out of the camera.
CR2 is the raw sensor data a Canon camera writes at the moment of capture. It's produced by the camera's own hardware and firmware — software can read it, but nothing can manufacture a genuine CR2 from a finished FITS.
Your FITS is a developed, final image. The extra sensor information a CR2 carries — wider dynamic range, full color depth, untouched highlights — was discarded when the photo was first saved, and can't be put back.
CR2 is proprietary to Canon. Even other RAW formats (NEF, ARW, RAF…) aren't interchangeable with it — there is no universal "save as RAW" that produces a real CR2.
Every real RAW file is one of these camera-maker-specific formats, written by the camera itself:
FITS (Flexible Image Transport System) is the standard format of astronomy, storing telescope and scientific image data with extensive metadata headers.
How to open FITS opens in astronomy software like SAOImage DS9, FITS Liberator and Astropy; convert to PNG/TIFF to view normally.
Full FITS format guideCR2 is Canon’s older raw photo format, holding unprocessed sensor data from EOS cameras for maximum editing flexibility.
How to open CR2 opens in Canon DPP, Lightroom, Photoshop and most raw editors.
Full CR2 format guideLossless and uncompressed — ideal for editing, archiving and print.
FITS → TIFFLossless with transparency — perfect for graphics, logos and screenshots.
FITS → PNGA small, universal photo format that opens everywhere.
FITS → JPGConvert your CR2 and other camera RAW files to JPG, PNG or TIFF.
Open the converter