11-11-2010, 10:03 AM
There's no such thing as a IS USM III.
Canon has 3x 70-300 IS lenses.
These two:
http://www.opticallimits.com/canon-eos/201-canon-ef-70-300mm-f45-56-usm-is-lab-test-report--review
http://www.opticallimits.com/canon-eos/200-canon-ef-70-300mm-f4-56-usm-is-test-report--review
Plus the new L IS.
Canon has 3x 70-300 IS lenses.
These two:
http://www.opticallimits.com/canon-eos/201-canon-ef-70-300mm-f45-56-usm-is-lab-test-report--review
http://www.opticallimits.com/canon-eos/200-canon-ef-70-300mm-f4-56-usm-is-test-report--review
Plus the new L IS.