When the Canon EOS R5 launched in 2020, the camera was an instant hit. The 45MP full-frame sensor delivers impressive image quality, and the Dual Pixel AF system excels. Among its most impressive specs is 8K/30p video, which was extremely unusual at the time and remains an impressive offering. However, amidst the camera’s fanfare, there was a lot of discussion about the camera’s thermal design, overheating and video recording limits. A new Canon patent application filed in the United States outlines an internal liquid cooling device for mirrorless cameras that could alleviate overheating concerns in Canon’s future video-centric cameras.

The patent application describes an apparatus with a conduit that circulates magnetic fluid using a magnetic field generator. ‘The conduit includes at least four areas of a first conduit area in which the magnetic fluid receives heat from a heating unit, a second conduit area from the first conduit area to a cooling unit, a third conduit area in which the magnetic fluid is cooled by the cooling unit, and a fourth conduit area from the cooling unit to the heating unit,’ Canon writes.

Figure 6 from Canon’s patent application US 2022/0264767. Figure 6 illustrates how a magnetic liquid within a conduit can transfer heat away from one area to a cooling unit and then cycle the cooled liquid back to the area that requires cooling. For example, a system like this could remove heat from an image sensor area and then cycle the heated liquid through to a cooling unit before returning it, now cooled, back to the sensor to regulate the sensor’s temperature.

Below is the full patent application, complete with many more interesting diagrams, including how the ferrous liquid is circulated surrounding an image sensor. Regarding liquid cooling, using a magnetic liquid is an uncommon cooling solution.

It’s not immediately evident when, or if, Canon will ever integrate a magnetic cooling system into one of its mirrorless cameras. However, it’s a fascinating solution to a problem that will only become more important to solve as cameras continue to feature increased processing power and sensor resolution, all while balancing performance against compact, lightweight camera designs.

Looking back at our original Canon R5 and R6 overheating testing, it was evident that despite some claims online that the cameras were poorly designed or underperforming against Canon’s claims, the R5 and R6 performed in line with the limitations Canon outlined when it announced the cameras. Of course, the limitations that Canon outlined are problematic for some users. Canon opted to omit an internal cooling fan from the R5 and R6 to help maintain a compact, lightweight and weather-resistant design. Is it possible that an internal magnetic cooling system could be integrated without sacrificing compactness or weather resistance? Time will tell.

Figure 12A shows a version of the cooling system within a camera body. In this diagram, item 608, shown in the camera grip, is the cooling unit.

If we consider solutions to the overheating issue that other manufacturers have employed, we’ve seen the Panasonic S1H incorporate an internal fan while Fujifilm’s new X-H2S camera uses an external fan accessory that can be attached to the back of the X-H2S body to significantly extends video recording times. Canon itself incorporated active cooling into the videographer-oriented version of the EOS R5 earlier this year, the EOS R5 C. The integrated fan allows for longer recording times. Of course, the result is a larger, heavier camera.

The Canon EOS R5 C incorporates an active cooling solution with an internal fan. The fan helps extend video recording times, but does come at the cost of size and weight.

For now, we must take a wait-and-see approach to find out if Canon will ever incorporate its impressive cooling solution into its cameras. We do know it’s possible to extend the shooting times of the Canon R5 camera using a liquid cooling solution, as DIY Perks modified an R5 with an impressive water-cooling system. You can check that project out below.