topic Re: extender rf 2.0 in Camera Accessories

EOS R100 and Extender RF2x compatibility

JENDUPLANTIS — Wed, 29 Oct 2025 02:39:04 GMT

I'm just a little confused. I have a beginner Canon EOS R100 and have purchased a new lens 100-400 and works fine. I first started with a used 75-300 EF mount with an adapter, then purchased used EF teleconverter so I got 150-600. I wanted to change everything to all RF mount lenses so I purchased the RF mount 100-400 lens. I was a little upset that the extender 2.0 was so expensive (more than the 100-400 lens that I purchased). I made sure the 100-400 lens was compatible with the rf 2x extender but now I've read somewhere the extender is not compatible with my camera EOS R100. It fits fine on my camera but I just want to make sure I'm not messing the camera up. I do want to eventually purchase a nicer camera (EOS R7). This bird watching hobby I started is quite expensive. Is it ok to use the extender on my camera without messing it up? I don't understand how it could not be compatible if it goes right on my camera no problem

Re: extender rf 2.0

deebatman316 — Wed, 29 Oct 2025 01:31:58 GMT

Teleconverters are NOT COMPATIBLE with the EOS R100. The problem is the older hardware in the camera body. Not the camera’s physical lens mount. Or the lens being used. I would avoid using teleconverters on your camera. Even though it may mount it’s not a compatible combination. It may or may not cause damage to your camera.

Re: extender rf 2.0

stevet1 — Wed, 29 Oct 2025 01:44:07 GMT

JENDUPLANTIS,

I was going to give you the same information that Demetrius did.

You can read this in a Canon website called Supplementary Information for the R100

https://cam.start.canon/en/H001/supplement_0170.html

Steve Thomas

Re: extender rf 2.0

JENDUPLANTIS — Wed, 29 Oct 2025 02:09:23 GMT

Thank you. How can I find the compatibility guide for the Canon EOS R7 which is the camera I want to upgrade to. Hoping the RF 2x extender is compatible with it and my 100-400 lens. I thought I was going to be able to use my R100 until I could upgrade the camera. I think I had a better set up with the used ef mount 75-300 with adapter and 2x teleconverter than i do now with the rf mount 100-400 for capturing birds in flight at a longer distance.

Re: extender rf 2.0

deebatman316 — Wed, 29 Oct 2025 02:16:46 GMT

Other RF Mount cameras are compatible with teleconverters. A long with lenses that support them. The official Canon teleconverters is NOT COMPATIBLE with the EF 75-300mm lens by design. Canon’s teleconverters protrude into the lens. Thus making that lens incompatible with official Canon brand teleconverters.

Re: extender rf 2.0

JENDUPLANTIS — Wed, 29 Oct 2025 02:33:36 GMT

I know the canon RF teleconverter is not compatible with the EF 75-300. My question was where do I find the compatiblilty guide for the Canon EOS R7 to make sure it is compatible with this almost $700 RF 2x extender I just purchased. I was using the EF 75-300 with an adapter and a differernt teleconverter on my EOS R100 when I decided to upgrade to an RF 100-400 lens but just found out I cannot use this RF 2x extender with my current camera (EOS R100). I want to upgrade my camera

Re: extender rf 2.0

deebatman316 — Wed, 29 Oct 2025 02:44:29 GMT

All RF Mount cameras are compatible with teleconverters. Excluding the EOS R100. The EF 75-300mm is NOT COMPATIBLE with official Canon brand EF Mount teleconverters.

Re: extender rf 2.0

JENDUPLANTIS — Wed, 29 Oct 2025 03:05:33 GMT

Thank you. I guess I just have the only RF camera that is not compatible. It is a beginner camera for me. I guess it's time to upgrade!

Re: extender rf 2.0

stevet1 — Wed, 29 Oct 2025 05:41:25 GMT

JENDUPLANTIS,

In reading through various Internet postings in different forums, it looks like your R7 would be compatible with a 2X extender - some posters actually speak of their experience using one' and as Demetrius said, the RF system, as a whole is compatible.

The only incompatibility appears to lie with the lenses.

From Canon's website on the RF 2X extender compatibility page:

RF400mm F2.8 L IS USM

RF600mm F4 L IS USM

RF600mm F11 IS STM

RF800mm F5.6 L IS USM

RF800mm F11 IS STM

RF1200mm F8 L IS USM

RF70-200mm F2.8 L IS USM Z

RF100-300mm F2.8 L IS USM

RF100-400mm F5.6-8 IS USM

RF100-500mm F4.5-7.1 L IS USM

RF200-800mm F6.3-9 IS USM

Steve Thomas

Re: extender rf 2.0

jrhoffman75 — Wed, 29 Oct 2025 10:02:56 GMT

Do you know what the actual incompatibility is?

Re: extender rf 2.0

deebatman316 — Wed, 29 Oct 2025 13:59:55 GMT

Yes it’s Digic processor it uses. It uses the Digic 8 processor found in many older high end DSLR cameras. Most EOS R series cameras use Digic X processors. Also the camera fps in stills mode is very low. It’s only capable of 6 fps in One Shot AF then in Servo AF only 3-4 fps. I don’t think this camera is fast enough to support simultaneous AF & Aperture control. A lot of older Arc Form Drive (AFD) EF lenses released between 1987-1990. Don’t support this either due to physical hardware limitations. The communication speed between the body and lens are just too slow. Micro Motor and USM lenses never had this issue from there beginning. They can drive both aperture and AF at the same time. Ring Type USM was first released in 1987. It is also one of the oldest AF motors still in production today. The only drawback to those older lenses. Is that they were focus-by-wire. So if the AF motor were to fail the lens became a paper weight. The last ever produced AFD lens was the EF 50mm F/2.5 Compact Macro lens. It was released in December of 1987 and discontinued a couple years ago.

Re: EOS R100 and Extender RF2x compatibility

ebiggs1 — Wed, 29 Oct 2025 17:54:50 GMT

If I were you I would avoid tele converters all together. A lens like the Canon RF 200-800mm f/6.3-9 IS USM Lens is a far better choice.

Re: EOS R100 and Extender RF2x compatibility

JENDUPLANTIS — Wed, 29 Oct 2025 19:12:28 GMT

I would love that if money was not an obstacle, lol. My next purchase will be a new camera for almost $1000 less than that lens.