Should I buy the Canon RF-S 10-18mm or RF-S 18-45mm?

The choice mostly comes down to how wide a view you need.

• Buy the Canon RF-S 10-18mm if you want the ultra-wide look for vlogging, landscapes, architecture, or tight indoor spaces. It’s the better pick when you need to fit a lot into the frame, especially for handheld video at arm’s length.
• Buy the Canon RF-S 18-45mm if you want a more general everyday zoom for travel, street shots, and casual portraits. It’s the more flexible all-purpose option when you don’t need an ultra-wide view.

If you can only buy one, I’d usually lean 18-45mm for general use and 10-18mm for a specific ultrawide need.

One important caveat: both lenses are designed for Canon APS-C RF-S bodies like the R50, R10, and R7. They can mount on full-frame EOS R cameras, but the camera will crop the image.

Also, the 10-18mm tends to do better at the edges, with less vignetting and sharper corners than the 18-45mm kit lens.