Canon gear - EF to RF mount

With the likelihood of Canon offering a EOS 7D mk3 pretty much being DOA, the question I'm shaping up is how to move forward, while hopefully retaining most of my legacy EF glass.

The newer Canon RF lens mount has an EF adaptor, so that's good, but since there's no APS-C RF body (although rumors of one), its brought about an interesting question on configurations going foward.

My current go-to longest lens combo is:

7D body (1.6x)
EF teleconverter (1.4x)
400mm DO IS f/4

....which results in a ~900mm equivalent @ f/5.6

If I were to replace the 7D with the (say) R6, the configuration would be:

R6 (full frame... 1.0)
RF-EF adaptor (1.0)
EF teleconverter (1.4x)
400mm DO IS f/4

... results in a 560mm f/5.6

To approach the baseline, there's a couple of options, such as:

R6 (full frame... 1.0)
RF-EF adaptor (1.0)
EF teleconverter (2x)
400mm DO IS f/4

... results in a 800mm f/8 (loss of autofocus?)

But would this also work?

R6 (full frame... 1.0)
RF 2× Extender
RF-EF adaptor (1.0)
400mm DO IS f/4

Namely, to put the EF converter *after* the RF extender. Anyone know?

The thought process is that I don't currently own an EF 2x, and the different generations of extenders don't always play nice, but moving the extender onto the RF side of the RF-EF conversion would sidestep this issue, as well as to potentially also permit:

R6 (full frame... 1.0)
RF 2× Extender
RF-EF adaptor (1.0)
EF teleconverter (1.4x)
400mm DO IS f/4

... results in a 1100mm f/11 (loss of autofocus?)


Thoughts?

-hh

In article a7956f46-b24e-4480-81a9-
,
says...

Thoughts?

How about just keeping the 7D (for the time being), or is there
a reason you must upgrade?
--
Alfred Molon

Olympus 4/3 and micro 4/3 cameras forum at
https://groups.io/g/myolympus
https://myolympus.org/ photo sharing site

On 1/8/21 3:22 PM, -hh wrote:
With the likelihood of Canon offering a EOS 7D mk3 pretty much being DOA

I believe the Canon R7 is coming later this year -- APS-C
sensor, R mount.

That will be the replacement for what might have been a "7D
mk3" ...

On Saturday, January 9, 2021 at 7:15:40 PM UTC-5, Alfred Molon wrote:
-hh says...

Thoughts?

How about just keeping the 7D (for the time being), or is there
a reason you must upgrade?

Oh, I don't intend to throw stuff away; its just that the 7D is already a decade old,
and its not going to last forever.

Likewise, my 7D Mk2 is a half decade old, so that's a longer term consideration too,
plus I use my 7D extensively Underwater, and even a 7D Mk2 isn't close enough to
physically fit in the existing 7D camera housing. Because UW housings aren't free
(or cheap), its generally foolish to buy a new housing for an old body.

-hh

On Saturday, January 9, 2021 at 11:13:01 PM UTC-5, Fishrrman wrote:
On 1/8/21 3:22 PM, -hh wrote:

With the likelihood of Canon offering a EOS 7D mk3 pretty much being DOA

I believe the Canon R7 is coming later this year -- APS-C
sensor, R mount.

That will be the replacement for what might have been a "7D
mk3" ...

I've done some more reading and yes, I saw that rumor. Makes for an interesting trade-off,
particularly since I shoot wide angle on my UW setup, so that tends to favor going to a FF
sensor for that.

FWIW, in doing a bit more digging, turns out that one of the questions I asked about isn't
feasible -- one can't mount the RF-EF converter downstream of an RF extender. As such,
the option there would be either RF 1.4 + RF 100-500mm (= 140 - 700mm @ f/~10) or
RF 2.0 + RF 100-500mm200 - 1000mm @ f/~13?) or