EF 600mm f/4L IS III USM on R6 body? Confused.

[irish_rogue]

Found a good local/used EF 600mm f/4L IS III USM, but am confused about the tradeoffs vs. the RF mount RF600mm F4 L IS USM...   Are there tradeoffs (beyond additional adapter?) that I should consider here?

[shadowsports]

Greetigs,

Its literally the lens mount.

Canon RF 600mm F4L IS USM vs Canon EF 600mm F4L IS III USM Detailed Lens Comparison (cameradecision....

[rs-eos]

I would only be concerned with where you'll be purchasing the used lens from.  If it's not an authorized Canon reseller or trusted used gear vendor (e.g. KEH), then it will be risky.   Canon sells refurbished lenses, so you should also take a look to see if the EF 600mm f/4L is listed there.

[ebiggs1]

I would not be overly worried about purchasing a used EF 600mm f4L. They are extremely well build. But as always it must be a try before you buy situation.. If you are not allowed to try it don't buy it. That's why KEH, B&H, Adorama and some others are choice sources. You have a trial period and a return privilege.