An older post in Apple Discussions had this comment from Canon.
Canon Support - Scanner writes:
``Thank you for your inquiry. We value you as a Canon customer and
appreciate the opportunity to assist you. We regret to hear that you
are experiencing difficulty scanning from Image Capture with your
CanoScan LiDE 80.
That is very strange that the CanoScan LiDE 80 would scan using the
Toolbox but not from Image Capture. The CanoScan LiDE 80 is not
supported on the Mac OS X 10.5 Leopard OS. We are sorry for any
inconvenience this may cause.
The following models are compatible with Macintosh OS X 10.5: 4400F,
8400F, 8600F, 8800F, 9950F, LiDE 25, LiDE 35, LiDE 60, LiDE 70, LiDE 90,
LiDE 500F, LiDE 600F.
Looking on Canon's site at http://www.usa.canon.com/cusa/support/consumer/scanners/canoscan_series/canoscan _lide_80#DriversAndSoftware the driver for the Lide 80 maxes out at OS 10.4
However, this link does have the Lide 80 driver http://driversbay.com/drivers/scanners/canon/canoscan-lide-80/apple-mac-os-x-10- 5-leopard/
After weeks and weeks of searching on forums, and installing all types of softwares to get my scanner canon lide 80 working on 10.5.8, and well after series of unsuccessfull days,
this morning I randomly installed the software found on canon site for the canon lide 35 scanner, and there I find out, my lide 80 is working on 10.5.8 !! with Canoscan toolbox 4.51 I just downloaded . So, here I am posting on this forum. I check again the canonscan Toolbox window, I realise it's not the 4.5.1 that is open (and working) but it's the 18.104.22.168 (2003 version). Sorry I cannot be more precise, I have downloaded sooo many versions, without necessarly uninstalling the previous versions. But well, there is some hope that if one mixes all of this, it works, just ok. Good luck.
I am using a mac pro desktop computer.