Note: 

I am far from being an expert on EXIF. This information has been compiled from EXIF specifications available from the EXIF.org website HERE, and from actual 1Ds EXIF data extracted using the useful EXIF Reader utility by Ryuuji Yoshimoto. I have done my best to interpret the rather confusing (to me at least!) information available, but I make no claim that it is 100% accurate and it should not be taken as gospel. A much more detailed explanation of EXIF compiled by TsuruZoh Tachibanaya can be found HERE.

What is EXIF?

EXIF is an acronym for EXchangeable Image File, an image data specification developed by the Japan Electronics and Information Technology Industries Association (JEITA). Originally developed to standardise digital photographic printing, it is often refered to as EXIF Print. The EXIF v2.1 specification relates to Digital Camera Files (DCF EXIF).

The DCF EXIF specification comprises a number of attributes that describe a digital camera image, such as date and time of exposure, aperture and shutter settings, focal length of lens, etc. Which attributes are used is optional and usually depends on the type and functions available in a particular camera.

This information is then embedded as Tags within the header of each image file and "travels" with it for as long as application software and image file format conversions support it. Further information may be added to the EXIF data by subsequent software processing such as RAW file conversion.

EXIF as created by the Canon EOS 1Ds

The following list of DCF EXIF Tags shows which are used during image exposure by the 1Ds camera:

Info included in my galleries where available
info recorded by camera but not included in my galleries
info not recorded by camera