Patent Reveal: Canon’s Motorized Built-in Extender – The End of the Lever?
Recent patent applications from Canon have revealed a fascinating new direction for their super-telephoto lenses: a motorized built-in extender. While lenses like the EF 200-400mm f/4L IS USM have featured a mechanical lever for engaging an internal 1.4x extender, Canon seems to be exploring an electronic, motorized solution for future RF-mount glass.
This development would mark a significant shift in lens design, moving away from physical switches and levers towards fully electronic control.
The Technology: A Look Inside
The core of the patent involves replacing the manual lever mechanism with a small, precise actuator or motor. This motor would be responsible for physically moving the extender’s optical group into and out of the light path. This is similar in principle to how autofocus motors move focus groups, but applied to the extender mechanism.
Below is a visualization of what this internal mechanism could look like, based on the patent concepts.
As you can see in this concept, a small motor and gear system is placed near the rear of the lens. With the push of a button, it would precisely slide the extender elements into place, transforming the lens’s focal length.
Potential Benefits: Beyond the Switch
So, why move to a motorized system? There are several potential advantages:
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Improved Weather Sealing: A mechanical lever requires a physical opening in the lens barrel, which can be a point of weakness for dust and moisture ingress. An electronic button or switch can be much more effectively sealed.
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Ergonomics and Speed: An electronic switch could be placed in a more ergonomic location, or even assigned to a camera button, allowing photographers to engage the extender without taking their eye off the viewfinder or changing their grip.
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Integration with Camera Features: A motorized system could be integrated with camera functions, perhaps allowing for automatic engagement based on subject distance or other shooting parameters.
Here is a concept of what the new electronic control might look like on the side of a lens:
This concept shows a sleek, low-profile rocker switch with LED indicators, a significant departure from the bulky levers of the past.
The Future of RF Super-Telephotos?
While a patent is not a guarantee of a final product, it strongly indicates the direction of Canon’s R&D. We’ve already seen patents for motorized tilt-shift lenses and other electronic lens controls, so a motorized built-in extender is a logical next step.
Could we see this technology in a future RF 500mm f/4 with a built-in 1.4x, or perhaps a new version of the 200-400mm? Only time will tell, but the future of Canon’s super-telephoto lineup looks increasingly electronic.
via j-platpat