Canon RF 28-70mm f/2L USM
The Canon RF 28-70 f/2L is the company's way of showing off. Most lenses is this class are at F2.8, but at F2.0 this lens lets in more light, and can make for more blurred backgrounds. Sharpness is exceptional, even wide open at F2 (where other lenses might suffer). This isn't the biggest zoom range, but if you need class-leading sharpness and low-light performance, the 28-70 has no competition. Be prepared to pay for it, though. At over 3lbs of glass and with a $3,000 price tag, this is definitely not an everyday lens.
Canon RF 50mm f/1.2L USM
Many photographers keep a cheap compact 50mm lens in their bags, but that is not what Canon has made here. The Canon RF 50mm F/1.2 is over 2 pounds and costs more than $2,000, but what you're getting for that is an incredible sharp lens with an ultra-wide aperture, perfect for super-blurred backgrounds or letting in tons of light. With no image stabilization and a noisy focus motor this is not a lens for video, but if you need a top-performing lens that takes full advantage of the new RF mount, the RF 50mm F/1.2 is the top of the class.
Canon RF 24-105mm f/4L IS USM
The Canon RF 24-105mm F4 is the "kit" lens for the company's new mirrorless camera, the EOS R, and you may be able to find the two together at a discount. The 24-105mm focal length makes for a versatile lens that can shoot reasonably wide and still provides a 4x zoom. Many 24-105 lenses lose sharpness above 70mm, but the RF 24-105 maintains good center sharpness even at 105mm. At F4, this isn't the best lens for low-light, but excellent lens stabilization means you'll be able to use it at slower shutter speeds. Like all Canon's new RF lenses, the 24-105 comes with a programmable control ring that can be set to change settings including aperture, shutter speed, or ISO.
Canon Control Ring Mount Adapter EF-EOS R
If you're looking to use older EF lenses with your new EOS R mirrorless camera, the Canon Control Ring Mount Adapter is a no-brainer. It lets you mount EF lenses to the cameras new RF mount and keeps autofocus or lens stabilization working. This mount comes in three flavors, one that is just an adapter, another that adds a customizable control ring, just like the native RF lenses have, and a model that lets you use drop-in polarizing or neutral density filters. These filters can be super-useful for filming in bright sun, but they're expensive. For anyone who doesn't need to swap filters in seconds on the fly, we'd pick up the control-ring model and stick with screw-on lens filters.
Canon RF 35mm f/1.8 IS Macro STM
The RF 35mm f/1.8 IS Macro STM is the least expensive of Canon's new RF lenses, and while $450 isn't cheap, it at least matches the price of Canon's previous 35mm f/1.8 lens. As a bonus, you get Canon's new customizable control ring, and a few features that seem designed for shooting video. This lens comes with image-stabilization, a relatively rare feature on lenses that can already let in this much light, but a must-have if you're going to try hand-held shooting on the unstabilized EOS R. Its STM focus motor is also designed for smooth focus transitions, a great feature for video.