ISO 12233 crops have been added to the Canon EF 300mm f/2.8 L IS II USM Lens Review page.
These results are very impressive. The Canon EF 300mm f/2.8 L IS USM Lens was one of Canon's best lenses. The 300 II bests it - especially with the new extender IIIs attached. As with the 400 II, the lighter weight of this lens over the previous model is very noticeable - and very welcomed.