TGA to ORF Converter

Encoding: the TGA uses uncompressed or run-length encoded (RLE); ORF uses losslessly compressed sensor data, with a preview and thumbnail, and the download is a Linear DNG: demosaiced 8-bit RGB with the colour matrices raw editors need.

Bit depth: 8, 15, 16, 24 or 32 bits per pixel in the TGA; ORF allows 12 bits per channel, and the DNG written here has 8 bits per channel, linearised.

Colour: RGB, greyscale or a colour map in the TGA; ORF supports camera RGB from a Bayer mosaic, written here as 8-bit sRGB.

Transparency: the TGA stores it as the fourth byte of each 32-bit pixel (or one bit in 16-bit files); the DNG has none, so transparent areas are filled with the colour you choose.

Metadata: the TGA can carry an image ID field and an optional extension area with author and date; ORF can carry EXIF and Olympus maker notes, which also contain the preview, but nothing is copied across.

TGA is a simple raster format still widely used for game textures and 3D rendering pipelines because it stores alpha channels reliably and loads fast.

A TGA has an 18-byte header (ID length, colour map type, image type 2 for true colour or 10 for RLE, origin, size, bits per pixel and a descriptor byte whose bits give the alpha depth and whether rows run top-down), then the pixels; version 2 files end with a 'TRUEVISION-XFILE' footer.

TGA files usually come from game engines, 3D renderers and texture painting tools.

ORF is the raw format of Olympus and OM System cameras, built around Four Thirds and Micro Four Thirds sensors. It stores 12-bit sensor data with a JPEG preview kept inside Olympus's maker notes.

ORF looks like TIFF but replaces the version number 42 with the letters 'RO', so a little-endian file starts 'IIRO' and generic TIFF readers reject it. Its JPEG preview is not in the main image directory but inside the camera-settings block of Olympus's maker notes.

ORF files come from Olympus E-series DSLRs, OM-D and PEN mirrorless cameras and OM System bodies.

Forms and workflows that ask for ORF usually feed a raw editor, and each of those opens DNG as well, so the DNG can take the ORF's place. Keep the TGA if you only need to view or share the picture.

What ORF offers when it comes straight from the camera: Compact files from a smaller Four Thirds sensor; High Res Shot results stored as a single file; Supported across two decades of Olympus and OM System bodies. Its drawbacks: An 'IIRO' header that generic TIFF readers reject; 12-bit depth, less than most full-frame raw files; A preview hidden inside the maker notes.