1.4 TC use for the R5 and R6

Since you mentioned the 100-500 you should be aware that if you use an RF TC it will not retract past 300mm. So your range is 300-700mm.

Some people are not happy with this for a few reasons. First obviously the restricted range and transportation. Neither of these bother me. I don’t ever recall shooting between 100 and 300 with my 100-400 and a TC. It’s on there for a reason.

As for transportation you remove it for travel. For local I purchased a plastic tool box that is wide enough to accommodate it with the TC including keeping the lens hood mounted for shooting mode. I did the same thing for my 400 DO so I could leave the lens hood on all the time.

John Sheehy wrote in post #19166094
Optically, yes, but you can't just randomly stack TCs of any type and expect the system to deal with it correctly, electronically. I find that many combinations just bang the IS (even if both IS and AF are disabled on the lens), or report communication errors. I am considering gutting some TCs and removing anything but pass-through, for stacking purposes. Also for AF speed purposes, as AF can work somewhat reliably without any AF speed governance caused by reporting TCs in good light and contrast. I find the more you cheat on AF speed governance with non-reporting TCs, the more likely focus is to jump quickly off-subject, after initially locking on in medium light, or overshooting in low light and/or contrast.

You've had this issue with the R5? Interesting. So far, none at all here. I've been mixing and combining Canon and Sigma T-Cons on Canon and Sigma lenses, maybe I've been lucky. I haven't tried the old Kenko I still have kicking around yet, the only reason I ever owned was because it didn't report. So really no reason to use it on the R5 with the reporting TCs working fine.

digital paradise wrote in post #19166204
Since you mentioned the 100-500 you should be aware that if you use an RF TC it will not retract past 300mm. So your range is 300-700mm.

Some people are not happy with this for a few reasons. First obviously the restricted range and transportation. Neither of these bother me. I don’t ever recall shooting between 100 and 300 with my 100-400 and a TC. It’s on there for a reason.

As for transportation you remove it for travel. For local I purchased a plastic tool box that is wide enough to accommodate it with the TC including keeping the lens hood mounted for shooting mode. I did the same thing for my 400 DO so I could leave the lens hood on all the time.

I guess we need to have SOMETHING to nit pick! lol

John Sheehy wrote in post #19166091
I don't recall whether such hacks allowed AF or any communication, myself, but my gut feeling is that the body might see the RF TC, talk in RF protocol, and not see the EF lens, like using a manual lens, unless the TC just has 8 pass-through wires to the EF-relevant pins, with no electronics on them, in which case AF and aperture control might work, but reporting may be absent, if the EF lens can't talk to the RF TC through the 3 extra EF-lens reporting-TC contacts. Canon might not have any motive for providing such communication or cooperation.

Do RF lenses and TCs have extra contacts for TC communication like EF does, or does the TC intercept lens/body communication. It would be interesting if the reporting was in-line, and still worked with an EF lens.

From the TDP article I linked to:
Being able to mount the extender behind the adapter was the first test to pass. Having the extender function properly in conjunction with EF lenses was the bigger question in my mind. Fortunately, the modified adapter passed that test also.

Note that this setup does not report the reduced aperture and increased focal length to the camera, but the camera continues to work normally.

So a question then,

Now that we have discerned that it is possible to HACK an RF adapter to allow the use of EF lenses with an RF Teleconverter...

.. was there an advantage?

Or is this like back when people would ask "can you mount an EF-S lens on a full frame camera" and people would answer "Yes"...


....you just have to chop up your EF-S lens with a dremel to MAKE it fit, and then pray the mirror assembly won't crash into the rear element"

To me, that answer really always meant "no"

The only reason I can see is that future proofing thing. You have EF lenses and you want to purchase a TC with the intent of getting RF lenses down the road.

I don’t know whey else anyone would want to do that. Only other thing is the hack is a “they said it couldn’t be done but I did” thing. All I can think of.

You can buy NC. Its best

Choderboy wrote in post #19166368
From the TDP article I linked to:
Being able to mount the extender behind the adapter was the first test to pass. Having the extender function properly in conjunction with EF lenses was the bigger question in my mind. Fortunately, the modified adapter passed that test also.

Note that this setup does not report the reduced aperture and increased focal length to the camera, but the camera continues to work normally.

Thanks; so we know that EXIF of the main lens parameters and aperture and AF motors work. The lens tested with is not IS, though, so we don't know if there are any issues with that. I suspect that Canon's newer bodies throttle power to the lens mount based on what the system thinks is attached to it, so there is some potential for too little power for the IS system. Almost every problem I have with TC combos on the R5 involves a lens with IS, usually a larger lens with IS.

Also, we know that the TC does not provide reporting of its presence in-line, with this EF lens and rig configuration, and likely all EF lenses with the same configuration of TC and adapter. If the RF system uses extra pins perhaps an adapter that added them too could work for reporting, but probably only if the lens/TC communication is the same as EF (not likely, I would guess).

digital paradise wrote in post #19166465
The only reason I can see is that future proofing thing. You have EF lenses and you want to purchase a TC with the intent of getting RF lenses down the road.

I don’t know why else anyone would want to do that. Only other thing is the hack is a “they said it couldn’t be done but I did” thing. All I can think of.

I really don't even see it as future-proofing. I would assume that anyone with EF mount telephoto lenses and an interest in using teleconvertors would already own EF mount TCs. Those TCs will work perfectly fine via the RF to EF mount adapter. The only reason to buy an RF teleconvertor is if you purchase an RF mount telephoto lens.

The only thing I can see it saving is the need to carry both RF and EF mount teleconvertors if you have a mixture of RF and EF mount telephoto lenses.

The most obvious advantage of the hack is using lenses that are not compatible with TCs physically.
eg the 24-70 2.8L that Bryan tried for his hack and the 70-300L. I know there are others.

The hack would also allow you to test for yourself to see if there is an advantage optically of the RF TC over EF TC, particularly in the case of owning the V1 or V2 EF TCs.
It could make selling existing EF TCs practical as RF TCs could be used for both EF and RF lenses.
Lose, forget, damage your EF TC and choose hack rather than replace the EF TC.

If Bryan's prediction comes true, third party adapters could be available in the future requiring no hack.

Scott M wrote in post #19166553
I really don't even see it as future-proofing. I would assume that anyone with EF mount telephoto lenses and an interest in using teleconvertors would already own EF mount TCs. Those TCs will work perfectly fine via the RF to EF mount adapter. The only reason to buy an RF teleconvertor is if you purchase an RF mount telephoto lens.

The only thing I can see it saving is the need to carry both RF and EF mount teleconvertors if you have a mixture of RF and EF mount telephoto lenses.

That would be another scenario and carrying less gear is always appealing. My thoughts were that someone has never owned a TC. They want one and are expensive. Why spend money on EF when they know they will be changing to RF over time. I was in one thread with this theme. Everyone is motivated by different needs.

digital paradise wrote in post #19166204
Since you mentioned the 100-500 you should be aware that if you use an RF TC it will not retract past 300mm. So your range is 300-700mm.

Some people are not happy with this for a few reasons. First obviously the restricted range and transportation. Neither of these bother me. I don’t ever recall shooting between 100 and 300 with my 100-400 and a TC. It’s on there for a reason.

.

If I understand correctly, the zoom range with the RF1.4 would be 420-700, not 300-700.

Dave63401 wrote in post #19166613
If I understand correctly, the zoom range with the RF1.4 would be 420-700, not 300-700.

Yes that is correct. I was thinking about the physical retraction limit point of the lens which is 300mm. I think pictures of that if you want to see them.

How about this 1x to 1.5x to 2x zoomable TC?

https://www.canonnews.​com …0x-zoomable-teleconvertor

Looks really interesting. It'll be awhile, though, before it hits the market as it's in the patent application stage.

SYS wrote in post #19166645
How about this 1x to 1.5x to 2x zoomable TC?

https://www.canonnews.​com …0x-zoomable-teleconvertor

Looks really interesting. It'll be awhile, though, before it hits the market as it's in the patent application stage.

$1,600?