Canon "Switchable" teleconverter rumor

A patent filing seems to indicate some work being done by Canon on a "switchable" teleconverter. See the link for details.

https://www.digitalcam​eraworld.com …ilt-into-an-rf-300mm-lens

That would be a very neat teleconverter, depending on how bulky it turns out though. I can see many long shooters enjoying it and being able to swap betewen say 420 and 600 on a 300mm f2.8 at a flick of a switch. Far faster and lighter than either changing the TC over or running two cameras on different lenses.

Overread wrote in post #18885013
That would be a very neat teleconverter, depending on how bulky it turns out though. I can see many long shooters enjoying it and being able to swap betewen say 420 and 600 on a 300mm f2.8 at a flick of a switch. Far faster and lighter than either changing the TC over or running two cameras on different lenses.

I would welcome a switchable 1.4x/2x, but it would be even nicer to have finer granularity, like 1/3 stop increments, and maybe go down to 1.26x and up a little above 2x.

I am very aware of how steep a cliff AF falls off of, when the open f-number gets just a little too high, and such granularity would allow one to choose the maximum
magnification that gives suitable AF ability for any given context. I find that there are situations where f/5.6 works great and f/8 is abysmal, even with the same center AF point. One or both of those 1/3-stop increments in-between may be closer to f/5.6 performance than 2x performance.

I wonder, though, if Canon's protocol allows recognition of anything but 1.4x and 2x, or 2.8x (as a so-far-unused) number.

Are there any reporting TCs that get 1.5x, 1.7x, or 3x that Canon bodies recognize as such? Or are they all non-reporting or wrong-reporting? I've never owned those magnifications.

Mirrorless brings about a change that makes these types of teleconverters more usable.

My M50 can AF at f11 during the day with a 2x on my Sigma 150-600. How crazy is that? This means teleconverters could be the next big thing to augment the mirrorless market, so a variable converter would be awesome, provided its IQ is as least as good as the dedicated fixed ones we have now. I would want a 1.4x to 3x all in one unit personally, it would be great to add to the 100-400.

I can also remember a feature in TC’s that I had back in the late 1960’s or early 1970. The lens elements were in a removable module so when they were removed you had an extension tube. I had a 1.4X and 2X version in a mount for my Konica Autoreflex gear. I don’t remember who made them, perhaps Vivitar as that was very popular back then.