Here is a review of the inexpensive Canon RF 24-105mm f/4-7.1 STM IS lens for the EOS R system. It seems the mechanical quality is the only good thing they found.

Optical Limits tested the Canon RF 24-105mm f/4-7.1 STM IS, and their verdict isn’t very positive:

In absolute terms, it’s clearly a sub-standard lens. Its native characteristics range from good to downright terrible. The miserable vignetting and distortions have to be seen to be believed. Conversely, the resolution is actually pretty decent – which is a bit of a pity because you just won’t use this lens without auto-correction.

That’s being said – it is highly unlikely that you invest thousands into a high-megapixel camera and then just a few hundred on a cheap kit zoom lens. The pixel-level sharpness increases towards lower sensor resolutions and the vast majority of users have cameras featuring 20 to 30 megapixels (as of the time of this review). Within this context, the Canon RF 24-105mm f/4-7.1 STM IS makes much more sense. The 24mm setting will still not be perfect here but it’s certainly usable.

[…] the mechanical quality of the lens is pretty good for a kit zoom lens. The used materials are of high quality. The (extending-)inner lens tube is a bit wobbly though and this seems to be a theme across Canon consumer-grade Canon lenses.

Read the review at Optical Limits…

Other reviewers have a less negative opinion about this lens. All Canon RF 24-105mm f/4-7.1 STM IS reviews are listed here.

The Canon RF 24-105mm f/4-7.1 IS STM sells at $399: [shopcountry 61487]

Key features:

• RF-Mount Lens/Full-Frame Format
• STM Stepping AF Motor
• Center Macro Focus, 1:2 Magnification
• Optical Image Stabilizer
• Customizable Control Ring
• Rounded 7-Blade Diaphragm