I have recently purchased a EOS 1N for a great price and now I can use the battery pack I purchased for my EOS 3 camera. Being that as it may I have noticed the EOS 1 focuses a lot faster than the EOS 3. It may have to do with the EC focus on the 3. Not that I will be loosing a lot of sleep over this but I find it somewhat perplexing that it does this. Most of the CF functions are set identical except for the EC functions. Let me know how your focus functions work on either camera.