List of Canon parafocal zooms (anywhere?)

[JohnByers]

I use a Canon EOS D30 with this zoom lens:

EF 28-105mm f/3.5-4.5 II USM

I was surprised to see that my zoom lens is not included in the parfocal zoom lens listing that you provided.

I generally make it a practice to zoom in and lock autofocus and autoexposure, and then zoom out for final composition before taking a photo. This is the procedure that I've been teaching in a digital photography class that I conduct.

Can you provide technical details, or suggest tests that I can conduct, to determine how severe the focusing error might be with the zoom lens that I use?

John Byers