Question about settings when using EF 2x III extender

[Joel Eade]

My experience is the same as with Kayaker ..... the loss of auto-focus will probably be a deal breaker for you but since it's a rental give it a try.....I am not very good at manual focus at high magnification.

The version III of the 2X converter can be used very successfully on f/4 or f/2.8 lenses.

With the 2X TC I can get very sharp RAW files from the following three lenses: 500mm f/4L, 300mm f/2.8L and the 70-200mm f/2.8L

I have seen plenty of very sharp images using it with the 400mm f/4L DO and the 600mm f/4L (I do not own either of these lenses)

If you need 800mm or more I would suggest you rent one of these to try out with the 2X TC

I suspect the 400mm f/2.8L would perform well too but I am mostly in to bird photography and it is not commonly used for birds.