TecPIV reads either 16-bit tiff files or adobe dng files, which are then converted to 16-bits tiff files. This allows abstracting the specificities of each camera make and model. The conversion from a raw image in the format of the camera maker (eg. .raw, .nef) is delegated to other existing software like Adobe DNG Converter.
However, despite being designed to be an open standard, the dng format produced by Adobe DNG converter is non-unique. You can specify some options when converting and not all options are compatible with how TecPIV reads the dng file.
Converting the raw files into DNG is advantageous because you can keep a copy of the files in a documented format, that preserves the colour information while the 16-bit tiffs employed for the PIV calculation are grayscale.
So here are some screen captures of Adobe DNG converter with the settings producing dng files which can safely be imported into TecPIV and converted to 16-bit tiff files.