When mounting lenses via a teleconverter like the Canon 2x, does the EXIF metadata record this information somehow? Will the recorded focal length be adjusted by the camera or the extender? Is there a metadata flag that indicates the presence of the extender during shooting?
When I use a third party teleconverter with a Canon lens, the EXIF records the lens only in the Lens field, but the actual Av and Focal Length are correctly recorded.
The EXIF info below is from a shot taken at maximum aperture and focal length of an EF 70-200mm f/2.8 L IS II + Kenko C-AF 2X Teleplus Pro 300. As you can see the aperture is recorded as f/5.6 and the focal length as 400mm.
When a Canon extender is used, the EXIF data includes the extender in the lens data.
Indeed the EXIF data records the use of a teleconverter. see the attached picture.
Here is a screenshot of the EXIF data of a photo as displayed by Apple Aperture. The labels are in German, but the values speak for themselves.
The picture was taken using a 200mm lens with the Canon 1.4x teleconverter (II), the resulting focal length of 280mm is recorded.
Depends on the extender, really. Third-party ones will not necessarily be visible in EXIF.
If it is a modern Canon extender on a modern Canon camera, then yes, the meta data will indicate this and the focal length will be correct and even the correction profiles (if your camera supports them) are specific to the extender and lens combination used.