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Any Canon EOS-RP to Celestron C90 adapter(s)?

JTTraverse
Contributor

I recently was given a Celestron C90 1000mm f/11 lens (fwiw it's the black model with wide gold band, looks very similar to the orange model). The original owner used a 2.5" adapter tube to attach it to a Canon T90 camera, which I think had an 'FD' lens mount.

I happen to own a Canon RP camera that I would like to use with this C90 lens, but it's been a strain trying to get specifics on what sort of adapter I would need. Unless there is a ready-made adapter exactly for this, I've presumed that I'll need a T-adapter as well as the right T-ring. So, does anyone know exactly what it will take to make this work?

I do understand that the spacing of the T-adapter and T-ring is vital for correct focus on this camera. One suggestion was to try an EF-EOS R adapter on the camera and then simply use an EF T-ring and T-adapter to attach it. But it seems to me that there must be a simple solution, like a T-adapter that screws directly onto the C90 lens mount and the other end attaches directly to the camera lens mount, or an RF T-ring on the camera.

If anyone has experience with this, or knows a right solution to make this work, I'd appreciate the help.

Thanks!!

6 REPLIES 6

Tintype_18
Authority
Authority

Can't answer your question but that is one big lens. What do you photograph?

John
Canon EOS T7; EF-S 18-55mm IS; EF 28-135mm IS; EF 75-300mm; Sigma 150-600mm DG

Waddizzle
Legend
Legend

When Canon released the Ra, I believe users were using the RF-EF mount adapters.

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"Enjoying photography since 1972."

FloridaDrafter
Authority
Authority

Hello, JT!

You may... MAY... be able to use a T-mount made for the EF mount and get the R=>EF mount adaper. This depends on how thick the T-mount adapter is, which I'm not familiar with. If it's too thick, it will mess with where the image circle falls on the sensor, if it works at all 🙂

Newton

ebiggs1
Legend
Legend

Check out the Celestron T Adapter C90. That is what I used but I didn't have an R series.

EB
EOS 1DX and many lenses.

Waddizzle
Legend
Legend

All the above suggestions are correct.  The key piece of information that hasn’t been mentioned is that you are going to need more than one adapter.

The telescope needs a T-mount adapter.  Next you’ll need a T-mount to EF adapter.  Finally, you’ll need an EF-RF mount adapter on the camera.  That’s three adapters.

Let’s review that.  The scope needs a T-mount adapter. The camera needs the RF-EF mount adapter.

Sitting between them you’ll need a T-mount to EF mount adapter.  

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"Enjoying photography since 1972."

Waddizzle
Legend
Legend

I quick search shows that there T-mount to RF  mount adapters from several manufacturers.  This would be a far less costly approach than my previous suggestion of using a RF to EF adapter.  This type is a direct connection to the scope. 

The image is neither a suggestion or an endorsement.  This model was at the top of my search list.

IMG_4499.jpeg

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"Enjoying photography since 1972."
EOS R6 V RF20-50mm F4 L IS USM PZ Lens Kit
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