adapter for Samyang 135mm F2.0 lens - Forums

I would like to buy a SAMYANG 135 F/2 lens. The camera will be the 533MC pro that I already own. Which lens mount would be most suitable, and which adapter should I use?

Which version of the lens? For the Canon version you can get the bayonet replacement.

https://www.firstlightoptics.com/adapters/astro-essentials-samyang-lens-to-m48-adapter.html

I haven't chosen the version yet. I'll choose based on what can be done with adapters that work best. And what about the back focus?

If you use that adapter, you have 44mm. That's enough for a filter wheel.

📷 1000014456.jpg

D. Jung · Dec 20, 2025 at 07:07 PM
If you use that adapter, you have 44mm. That's enough for a filter wheel.
📷 1000014456.jpg

That looks awesome!

Struggled with an E-mount one.

I tried to print an adapter but the tilt was huge.

Ended buying a canon mount fisheye just to get the right ring, then bought the M48 adapter from FLO.

To avoid any tilt issues, I printed 2 rings for the lens and one for the amera because of the EFW weight.

📷 Image PNG.png

Wandrille VINCENT · Dec 20, 2025, 06:51 PM
I would like to buy a SAMYANG 135 F/2 lens. The camera will be the 533MC pro that I already own. Which lens mount would be most suitable, and which adapter should I use?

I have the Nikon version of the Samyang 135mm which has 4 screws (Canon has 3) and can’t find an adapter for that. If anyone has I would be pleased to hear from you.

They sell adaptors to M42 male off eBay or AliExpress, 15mm thickness, if this can help. Otherwise maybe you can use one of the ZWO adaptors:
ZWO Nikon Lens Adapter for ZWO 2" EFW and ASI6200 / ASI2600 / ASI2400 Cameras - Z415-EFW2-Nikon

David Carr · Dec 21, 2025 at 10:54 AM
Wandrille VINCENT · Dec 20, 2025, 06:51 PM
I would like to buy a SAMYANG 135 F/2 lens. The camera will be the 533MC pro that I already own. Which lens mount would be most suitable, and which adapter should I use?
I have the Nikon version of the Samyang 135mm which has 4 screws (Canon has 3) and can’t find an adapter for that. If anyone has I would be pleased to hear from you.

You mean this one?

📷 IMG_1531.pngEdit: thread on CN:

https://www.cloudynights.com/forums/topic/939531-my-rokinon-135mm-modifications/#comment-13725865

I doubt it. It is meant to replace the bayonet flange with a M48x0.75 male.

For me, to avoid tilt issues from lens adaptors and have more backfocus, I would buy the canon version and the FLO m48 thing.

I have this lens and I love it. But it took a fair bit of fiddling to get it just right. I bought the Canon version so that I could use the Flo adapter. This significantly reduces the risk of tilt. I use the lens with a step down ring to reduce the open aperture, so it shoots at f2.7 in order to get better stars. You will have to use shims between the lens and the camera to get the backfocus dialed in. Even at f2.7 the depth of field is incredibly narrow. The lens will platesolve to 130mm rather than 135. Some folks have trouble getting focus and need to remove the infinity stop on the lens. If you find this necessary, Nico Carver has a video on how to do so. If you plan to use filters, make sure they are all the same thickness. Otherwise you will have to redo your backfocus shims whenever you change filters. I use the Astrodymium ring system with mine, and it is very good.

Here to second the recommendation for the Canon version. The Nikon bayonet is sometimes fine, but is often too floppy for astro purposes. And like others mentioned, you can swap it for an Astro Essentials M48 adapter, which lets you get a bit of backfocus (and a much more standard threaded connection), but it’s only compatible with the Canon-mount Rokinon/Samyangs: https://www.firstlightoptics.com/adapters/astro-essentials-samyang-lens-to-m48-adapter.html

In fact, with the M48 adapter, you get 44mm of backfocus so you can actually fit a rotator + EFW behind the lens (specifically it has to be the Wanderer Mini v2, QHY CFW Ultra Thin, and one of the shorter BFL QHY cameras). It winds up being an incredibly powerful setup this way. This is a config I’ve been eyeing as a second rig:

📷 image.png

The Nikon bayonet is perfectly fine and the Nikon version is optically superior. Given that the OP is going to use a IMX533 OSC based camera all this talk of fitting a frigging FW is quite well over the frigging point, isn't it?

andrea tasselli · Dec 21, 2025, 05:23 PM
The Nikon bayonet is perfectly fine and the Nikon version is optically superior. Given that the OP is going to use a IMX533 based camera all this talk of fitting a frigging FW is quite well over the frigging point, isn't it?

That's an interesting thought. Both have the same optical design with 11 lenses in 7 groups, same coatings, same material. As far as I know, even the published MTF charts are the same for both versions. In which aspect would you say is the Nikon version optically superior to the Canon version?

Longer backfocus makes for flatter field (in this specific instance). And I have tested both versions and kept the Nikon one. In addition you get 2.5mm extra backfocus which can't be a bad thing.

Forgot to mention: The Nikon version got a manual iris.

andrea tasselli · Dec 21, 2025, 05:45 PM
Longer backfocus makes for flatter field (in this specific instance). And I have tested both versions and kept the Nikon one. In addition you get 2.5mm extra backfocus which can't be a bad thing.

I must be missing something. As far is I know, the backfocus is also the same for both, it's just that the Canon metal tube is 2.5mn longer to accommodate for the shorter flange to sensor distance of Canon. I'm not immediately seeing how that would impact the flat field-ness of the image.

My Canon version has a manual iris ring 😬

The one I tested was different then. Branded Rokinon I reckon. Fact is all I have seen from the Canon variant weren't as good as the Nikons.

Wandrille VINCENT:
And would this one be suitable for a cannon ED?

https://www.etsy.com/fr/listing/1738864858/adaptateur-samyangrokinonwalimex-vers?ref=cart

Avoid plastic at all costs. Get the FLO one, they ship to the US too, AFAIK.

andrea tasselli · Dec 21, 2025, 08:51 PM
Wandrille VINCENT:
And would this one be suitable for a cannon ED?

https://www.etsy.com/fr/listing/1738864858/adaptateur-samyangrokinonwalimex-vers?ref=cart

Avoid plastic at all costs. Get the FLO one, they ship to the US too, AFAIK.

I'm in France and that's the problem.

ZWO make a dedicated bracket for the 533MC Pro - and all cooled cameras.

Here is mine with the Samyang 📷 20251222_212303.jpg85mm.