Canon has released firmware updates to five RF-mount telephoto lenses.

• RF100-300mm F2.8 L IS USM Firmware Version 1.0.6
• RF400mm F2.8 L IS USM Firmware Version 1.0.6
• RF600mm F4 L IS USM Firmware Version 1.0.6
• RF800mm F5.6 L IS USM Firmware Version 1.0.4
• RF1200mm F8 L IS USM Firmware Version 1.0.4

Even with fast zoom operations, it is now easier to focus (RF 100-300 f/2.8L IS USM Only). The electronic shutter system has improved the control of the panning assist after the second continuous shot.

I am unsure exactly what ‘easier to focus’ means in Canon’s vernacular. Perhaps they mean quicker or better to focus? Or Both? In any case, that comment only applies to the new 100-300mm f2.8L IS RF lens. The other note concerns all the telephoto lenses noted above and panning assist – a feature I have only begun to dabble with so far. Nevertheless, it is always recommended that the firmware be updated to the latest.