Important Reminders Before Usage
| < 500g |  |
| 1. Avoid Using Overweight Lenses | 2. Different operation on lenses with different lengths |
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Operational Video Tutorial
M2RF Software Tool used is Version 1.0
Understanding Aperture on the M2RF
The adapter cannot directly control or read the lens focal length and aperture values. When shooting, you must manually adjust the aperture ring on the lens body. It is critical to use lens data tool that precisely matches the actual focal length and aperture of the lens to ensure the best stabilisation and autofocus performance
Here’s how that syncing works, in three parts:
| Set up your lens info – using Megadap Custom Tool on a computer | Control the aperture manually (every time you shoot) | Check the sync |
| Using the free “Megadap Custom Tool” software, you type in details for up to 4 lenses — name, focal length, and aperture values.
This data gets sent to the adapter and is later written automatically into your photos’ EXIF (metadata) info. A default lens profile can be chosen in the custom software; please use the chosen default lens during first use. |
Turn your lens’s aperture ring to one of the 4 specific values already saved in your active profile
Then flip the adapter’s 4-step lever to the position corresponding to that f-stop, based on how you configured it in the Custom Tool. |
Make sure the aperture number shown on your camera’s screen matches the number you physically set on the lens. |
⚠️ Why this matters: If the lens data doesn’t precisely match your lens’s real focal length and maximum aperture, autofocus speed and accuracy will suffer — you may see the camera “hunt” for focus or miss focus entirely.
Factory-Preset Lens Data
The adapter ships with four built-in lens profiles (A, B, C, D) already loaded with data for popular classic lenses. You can use these if you have these lenses or overwrite them with your own lens details using the Custom Tool.
What “A (F2.2)” Actually Means
The number in parentheses is a fixed selector code, not the lens’s real aperture. A, B, C, and D are four storage slots for lens profiles; since the adapter has no screen or buttons, it reuses your camera’s aperture dial to pick which slot to load. For example, Slot A is dial-coded “F2.2” but actually stores an f/1.4 lens — the dial code and the lens’s real aperture are two separate numbers.
| Camera Aperture Dial Setting | Loads | Real Lens Aperture (Factory Example) |
| F2.2 | A | f/1.4, f/2, f/2.8, f/4 |
| F2.5 | B | f/2 f/2.8, f/4, f/5.6 |
| F2.8 | C | f/2.8, f/4, f/5, f/5.6 |
| F3.2 | D | f/1.2, f/1.4, f/2, f/2.8 |
Step 1: Installing the Custom Tool Software – To customise your M2RF to fit your lenses
If your lens isn’t in the preset list, use the free Megadap M2RF Custom Tool Version 1.01 app on your computer:
- Download it from the official Megadap website or the documentation package (see download links at the end of this guide).
- Connect the adapter to your computer.
- Pick which slot you’re editing — Slot A, B, C, or D — from the dropdown & Enter your lens’s name, focal length, and aperture values.
- Enter your four aperture values in ascending order (smallest f-number first).
- Click Save to Adapter to write the data to the adapter.
⚠️ Mac users: For first-time use, please go to Settings> Privacy & Security > and select” Open Anyways”
Step 2: First-Time Setup
Follow these steps the very first time you use the adapter:
- Mount the M2RF adapter onto your RF-mount camera body.
- Mount your M-mount lens onto the adapter. ( In the custom software you can choose a default lens profile, please use the default lens data for first setup)
- Rotate the lens’s focus ring to the infinity (∞) position. ( For using lenses with 50mm focal length or wider )
- Turn on the camera.
- Turn the lens’s aperture ring to one of that profile’s four aperture values ( Configured previously using the custom software )
- Flip the adapter’s aperture lever to match — the lever’s 4 positions line up in order with the profile’s 4 values (1st position = 1st value, 2nd = 2nd, and so on set in the custom software)
- Check the camera screen — the aperture value shown on the camera body should match the actual aperture you set on the lens.
Step 3: Changing Aperture While Shooting
Once everything is set up, changing your aperture mid-shoot is simple:
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| Rotate the Lens | Match the Lever | Check the Screen |
| Turn the lens’s ring to your desired aperture | Move the 4-step lever to the stop number you assigned that aperture in the Custom Tool (e.g., F2.8 = “Stop 2” → move to Stop 2) | Confirm the camera’s displayed value now matches your physical setting |
⚠️ Always make sure your physical lens matches the active lens profile on the adapter (A, B, C, or D). If they don’t match, the camera will display the wrong aperture value.
Switching to a Different Lens (Changing Lens Profile)
If you want to swap in a completely different lens (say, moving from Lens A to Lens C), follow this exact sequence:
- Turn off your camera body.
- Remove the current lens and attach the lens you want to switch to.
- Turn the camera back on and set it to M (Manual) or Av (Aperture Priority) mode.
- Press and hold the AF/MF button for about 3 seconds.
- Rotate the camera’s aperture dial to the selector code for the slot you saved your new lens under, while holding the AF/MF Button — remember, this number is just a menu code, not your lens’s real aperture:
- F2.2 → loads Slot A
- F2.5 → loads Slot B
- F2.8 → loads Slot C
- F3.2 → loads Slot D
- Take a photo — this saves your selection.
- Turn the camera off.
- Wait about 5 seconds for the adapter to fully retract.
- Turn the camera back on.
- Your newly selected lens profile is now active.
M2RF Custom Tool Download
FOR WINDOWS USERS
FOR MacOS USERS
⚠️ Mac users: For first-time use, please go to Settings> Privacy & Security > and select “Open Anyway”
Switching Lens Profile – Unable To Switch Lens Data Fix
On the EOS R1 and EOS R5 Mark II, long-pressing the AF/MF multi-function button to switch lens data may make the aperture value jump briefly and then snap back — so the aperture can’t be set to 2.2 / 2.5 / 2.8 / 3.2
Follow this exact sequence to resolve the issue:
1. Confirm that the camera is set to M ( Manual ) mode or AV ( Aperture Priority ) mode in still photo shooting mode
2. In the shooting menu, set [Blackout-free display] to [OFF]
3. Set ISO speed to AUTO
4. Try switching lens data again