MOUNT CONVERTER MC-21

Available mounts

sigma sa-mount

canon ef mount

The SIGMA Mount Converter MC-21 is a high-performance lens adapter that enables the use of SIGMA SA-Mount or Canon EF-Mount lenses on L-Mount mirrorless camera bodies (such as those from SIGMA, Panasonic and Leica). It ensures full mechanical and electronic integration, preserving lens functionality and enhancing system flexibility.

Key Features

Lens Compatibility:
Converts SIGMA SA-Mount or Canon EF-Mount lenses to L-Mount camera bodies
Full Functionality:
Autofocus (AF-S mode only)
Optical corrections supported (peripheral illumination, chromatic aberration, distortion)
Aperture control
EXIF data transmission (lens type, focal length, F-number)

Camera Integration:
Supports camera-based correction features
Compatible with auto-crop function for APS-C lenses on full-frame bodies.
Optimized autofocus and aperture control via pre-loaded lens data

LED Indicator:
Displays lens compatibility and firmware status
Blinking orange indicates firmware update required
Internal Flocking:
Reduces internal reflections for improved image quality
Tripod Socket:
Included for better stability with large lenses
Removable with supplied tools
Firmware Updatable:
Future lens data stored in the lens itself
No need to update MC-21 firmware for new lenses
Firmware updates via SIGMA Optimization Pro software

Specifications

Material: Metal and plastic
Color: Black
Weight: Approx. 145 g
Dimensions: Ø69.6 mm × 24 mm
Accessory Type: Mount Converter
Available Versions:
MC-11 SA-E (SIGMA SA-Mount to L-Mount)
MC-11 EF-E (Canon EF-Mount to L-Mount)

Included Items

Front and rear caps
USB cable for firmware updates
Tripod socket and hex key

Use Cases

Expanding lens compatibility for L-Mount users
Preserving investment in SIGMA or Canon EF lenses
Ideal for professionals using multiple systems
Enhancing flexibility and value of existing lens assets

Additional Notes

Not compatible with AF-C mode or continuous autofocus in video
Teleconverters are not supported
Compatible with SIGMA UD-11 USB Dock for customization and updates
For best performance, keep firmware updated via SIGMA Optimization Pro

FEATURES

PRODUCT LINEUP

The new mount converter enhancing the extensibility of the L-Mount system.

The Sigma MOUNT CONVERTER MC-21 allows Sigma SA mount and Sigma’s CANON EF mount interchangeable lens owners to use their lens investment on L-Mount camera bodies. The converter allows more freedom of choice for L-Mount cameras, enhancing the extensibility of the L-Mount system.
Effective use of lens investment

Attaching the MC-21 to your collection of Sigma SA mount and Sigma’s CANON EF mount compatible lenses* allows them to be used as L-Mount system lenses, promoting the effective use of valuable lenses already owned.
* See the list of compatible lenses below.

* Sigma’s CANON EF mount compatible lens
Interchangeable lenses available to be used for
L-Mount cameras

The MC-21 increases the number of interchangeable lenses manufactured by Sigma that can be used with the L-Mount system. Compatible with the autocrop function, mounting APS-C size image circle DC lenses to a camera body equipped with a 35mm full size sensor still allows immediate use for shooting.
Compatibility
Simple interface

Whether the mounted lens is compatible or not is instantly visible from the color and the on/off of the MC-21’s built-in LED. The LED also notifies the user when a lens firmware update is available.
Lens data is pre-loaded

Running the data pre-loaded in the MC-21 for each lens by the special control program, autofocus and aperture control have been optimized. Regarding lenses to be released in the future, data for operating these lenses via the MC-21 will be stored in the lens. It means no firmware updates of the MC-21 will be required to use those new lenses. In addition, the MC-21 also supports correction functions of camera such as peripheral illumination, chromatic aberration of magnification, and distortion.
Other features

Fast and accurate auto focus

High precision AF photography in AF-S mode is achieved.
Note: Not compatible with AF-C mode.
The inside surface of the barrel is covered with flocking to eliminate internal reflections.

To prevent a reduction in lens performance due to internal reflections, the inside surface of the barrel is covered with flocking.
Comes with a tripod socket

Equipped with a socket for attaching the tripod*. Lenses not equipped with a tripod socket can be used by mounting the tripod to the MC-21.
* The tool supplied makes attaching/detaching possible.
Inclusion in Exif data

Information such as lens type, focal length, F number, and other tags are embedded as Exif data in each image file.
Notes
Notice on usage of the Sigma Mount Converter MC-21 when it is used in combination with Panasonic L-Mount cameras.
- Please update the firmware of the MC-21 and the camera to the latest version.
- Only AF-S works in Autofocus Mode. AF-C cannot be selected.
- The Auto continuous operation cannot be used during video shooting.
- Touch AF cannot be used.
- With lenses incorporating MO (Manual Override), operation in manual mode is possible only after focusing.
- MF guide is not available.
Compatible cameras
Notice on usage of the Sigma Mount Converter MC-21 when it is used in combination with Leica cameras.
- Please update the firmware of the MC-21 and the camera to the latest version.
- The Sigma MC-21 cannot be used with Leica cameras (Leica T, TL, TL2, CL, SL) released before the announcement of the L-Mount Alliance.
- Only AF-S works in Autofocus Mode. AF-C cannot be selected.
- Only MF can be used for focusing during video shooting.
- With lenses incorporating MO (Manual Override), operation in manual mode is possible only after focusing.
- MF guide is not available.
- The Optical Stabilizer function can be switched ON and OFF only by using the OS switch on the lens body.
- The AF Function button available on some lenses cannot be used.
Compatible cameras