topic Re: Canon Extender RF 2x/1.4x with Tamron EF lens and ER to R control ring in Gear Guide

Canon Extender RF 2x/1.4x with Tamron EF lens and ER to R control ring: Pros & Cons?

carmelstickyrol — Tue, 13 May 2025 13:12:09 GMT

Hello Canon site,

I am looking for advice on the pros and cons for adding in a teleconverter OR is the following even a plausible thought…..

I have the following equipment:

Canon EOS Ra

Tamron SP 150-600mm f/5-6.3 Di VC USD G2 for Canon EF

Canon Control Ring Mount Adapter EF-EOS R

I would like to hear some pros and cons on adding in one of the following to this configuration.

Canon Extender RF 2x

Canon Extender RF 1.4x

The two teleconverters are of different “thickness”. Will either one come in to play with the focal point considering that a mount adapter is in the mix?

What will be any changes to the maximum aperture?

If the canon teleconverters are not correct for this situation are there any links to a correct teleconverters?

Thanks for your insight and ideas and conclusions

Re: Canon Extender RF 2x/1.4x with Tamron EF lens and ER to R control ring

deebatman316 — Tue, 13 May 2025 00:17:40 GMT

RF Mount teleconverters are NOT COMPATIBLE with the EF-RF Mount adapter.

Re: Canon Extender RF 2x/1.4x with Tamron EF lens and ER to R control ring

carmelstickyrol — Tue, 13 May 2025 02:49:34 GMT

agree….. thinking RF and meant to type EF…. mind and fingers doing two different things… my questions still apply for understanding

Re: Canon Extender RF 2x/1.4x with Tamron EF lens and ER to R control ring

p4pictures — Tue, 13 May 2025 07:20:24 GMT

Firstly you cannot physically mount the RF extender in to the back of the RF to EF mount adapter. The inner diameter of the mount adapter is too small.

If you put the Canon EF extender on the mount adapter that will fit, but the Canon extender protrudes inside the rear of the lens it is fitted to. This is why extenders are only compatible with a limited range of EF lenses - those with space inside the rear of the lens to accommodate the front part of the extender. You will need to search around to find out if anyone has tried the Canon EF extender with the Tamron 150-600mm, and also check that when the lens is zoomed the rear element does not move to impact the front of the extender.

If Tamron has an extender compatible with the lens that would be the best option, though I am not sure that is possible given that the Tamron website does not list any extender as a compatible accessory. I do know that Kenko brand extenders do not have the protruding part on the front of the extender so can be used with most lenses. However optical quality is not so high.

Re: Canon Extender RF 2x/1.4x with Tamron EF lens and ER to R control ring: Pros & Cons?

ebiggs1 — Tue, 13 May 2025 14:55:50 GMT

I have the Sigma 150-600mm f/5-6.3 DG DN OS Sports Lens and a host of the other models in this FL zoom range. I have the Sigma 1.4x tel-con and all I can say is it works. I see no any reason why that combo would not work with the RF to EF adapter. I also can not see any reason why anyone wants to do it. You never get anything for free in photography. You alway give to get. The penalty to me is not worth the benefit.

I personally don't have the Tamron 1.4x so I can't say personally since I have never tried it on any of my Tamron lenses. I don't even know if it is still in production but it is probably the way for you to go. Still bottom line I wouldn't do it.