RF 400, or EF 400 with adapter?

Tambopata wrote:

PicPocket wrote:

Tambopata wrote:

tkbslc

It's the exact same lens with the same motors, how could it perform AF better?

It's all in the electronics. The RF mount has more connectors than the EF mount (12 vs 8 if I recall correctly), probably more power can be delivered to drive the AF-motors faster, more AF actuations per second to deliver faster and more precicse AF. Canon is quiet about it, but my guess is that all the wireing is changed to allow for complete access to the RF protocol.

Probably. Guess.

If we are guessing, my guess is that it is the exact same lens as EF version with the adapter bolted on. The adapter has 12 pins too. My guess is this is no different

The adaptor has 12 pins to make it compatible with the RF mont, EF mount still only has 8 pins, and that's potentially lots of info lost in translation.

That statement made me wonder why my control-ring-less Meike adapter had all 12 contacts on the camera side. I looked with an ohmmeter (low voltage one driven by a 1.3v AA battery), and found that two of the 12 contacts were shorted together. Counterclockwise, it is the first contact in each group. Maybe that's a signal that the camera needs to operate an EF lens, rather than querying the lens?

My guess again is that the full answer is connected to the release of the R3. Maybe only the RF-version is able to do 30 fps.

Is the R3 claimed to shoot 30fps with m-shutter, or just with e-shutter? E-shutter should have no necessary lens requirements for max speed. With the R5, the lens stays stopped-down during e-shutter bursts. Where the aperture motor speed or communication speed could matter is when using an exposure mode that varies the Av. The R5 allows AIServo at full e-shutter burst speed with any slow-to-AF lens; the focus just isn't as close to perfect in a larger percentage of frames.