# R5 + Old EF Lens AF Experiences



## analoggrotto (Aug 15, 2020)

I have an old NON-IS 300mm F2.8 L. Despite the awful minimum focus distance, I do still love this lens and would very much like to keep it for when my R5 arrives in time for whenever it arrives. 

Curious if anyone here has had any extensive experiences with first generation EOS lenses such as these and if that headlining AF applies here as well. 

I originally used this lens on a 5D Mark III, AF could be very difficult at times, the 5D Mark IV really speed things up (I hear it runs a higher voltage to the lens' AF motor). Similarly, with the 50L, the Mark IV eliminated the low light AF inaccuracies which plagued my old Mark III. 

Funny story on the 300mm F2.8L; as it gets some interesting attention out in the world, one drunken old fool threatened to call the US Navy on me for using it in public.


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## tron (Aug 16, 2020)

5DIV does not have give higher voltage to the lens. Only the 1D series do that.

It has better AF than 5D3 though. (I have upgraded from 5D3 to 5D4).


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## analoggrotto (Aug 16, 2020)

tron said:


> 5DIV does not have give higher voltage to the lens. Only the 1D series do that.
> 
> It has better AF than 5D3 though. (I have upgraded from 5D3 to 5D4).


Ok, thanks for the clarification. 5D4 eats the battery much faster than the 5D3, it's working much harder. 

Still curious he R5 moves the old EF glass, but im still getting it.


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## nc0b (Aug 29, 2020)

Has anyone used a 400mm f/5.6 L, which as no IS, on an R5 with IBIS? I still prefer this old prime over my 100-400 II for BIF due to its optional 8.5m close focus limit. I wish the zoom had an additional 10m focus limit option so AF can't get so easily lost in a clear blue sky. Of course I wish the 400 5.6 had IS like the 300 f/4.0, but it doesn't. 

Does IBIS provide a stable image through the EVF? How does IBIS compare to IS in the lens for 400mm and longer focal lengths? Since the 100-500mm RF zoom has IS in the lens, does that imply IBIS isn't very effective for long lenses?

The IS in my Canon 10x42 L IS WP binoculars (500mm equivalent) is simply stunning. I cannot imagine owning 10X binoculars without IS, and this L version runs circles around non-L Canon binoculars with IS as far as image quality.


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