For standard EXIF tags, start with the official CIPA EXIF specification (EXIF 2.3 and later). That’s the authoritative reference for common fields such as ISO, aperture, and shutter speed.

For Sony-specific metadata, especially maker-note tags, the most practical references are the tag documentation from ExifTool and Exiv2. Those projects document many manufacturer-specific fields, including Sony tags, and are often the easiest way to match tag IDs to readable names and values.

Also note that not everything you want is necessarily stored in EXIF:

• Image width/height and megapixels are typically from the JPEG image data itself, not EXIF.
• “JPEG quality” labels like Sony Extra Fine/Fine/Standard are generally derived from JPEG encoding characteristics (such as compression quality and possibly chroma subsampling), not always from a dedicated EXIF tag.

So in practice:

1. Use the CIPA EXIF spec for standard tags.
2. Use ExifTool/Exiv2 docs for Sony maker notes.
3. Check whether a value comes from EXIF, maker notes, or the JPEG structure before expecting a tag for it.