Greetings,
Let's start with this. When you use a lens intended for full frame body on a on a body with an APS-C sensor the field of view changes by a factor of 1.6x.
So the RF16mm (for example) will give a equivalent FOV of 25.6mm
Primes are nice, but I feel you.might be better served by a zoom which will also give you additional versatility.
If you are going to shoot indoors with good lighting, the kit lens RF-S 14-30 f4-6.3 STM PZ is a nice option. I own this body and lens. It's a nice combo but it does not do well in low light. You also don't get a great deal of background blur if the background is close to your subject. This may not impactful for stationary art videos.
I use the BR-E1 Bluetooth controller which allows you to zoom, snap pictures and start and stop video. You can use the Canon Connect app also, but it doesn't offer the same zoom capability as the wireless controller I mentioned above.
In my opinion Sigma is making some the best APS-C lenses currently. While the Sigma lenses don't have image stabilization, this won't matter for you since you'll be using a tripod 90% of the time.
The Sigma 18-50 f2.8 for Canon RF is about $159 above your budget. It would be my choice over the Canon RF-S 14-30 due to its f2.8 constant aperture. It offers a MFD of 4.8 in. It's not a true macro lens at a 1:2.6 ratio but still offers good close up capability at 18mm.
About the lenses on your list
Canon RF35mm F1.8 is Macro STM Lens (Would this be good for close up on my art with the macro)
A: This lens will provide an equivalent field of view of 56 mm. Since it has macro capability it's 1:2 ratio means your subject will be 50% of its actual size on the sensor. It's MFD is 6.7 in.
Canon RF16mm F2.8 STM Lens (wide enough to cover my desk)
A: Will provide a equivalent FOV of 25.6 mm. It would easily be wide enough to cover your desktop space. It's macro ratio is 1:3.8. Not great for close ups. It's MFD is 5.1 in.
Canon RF50mm F1.8 STM Lens
A: This lens will provide an equivalent field of view of 80mm. This will be awkward and challenging for your intended use, I would not consider this lens.
Or Just get the Kit Lens, Canon RF-S14-30mm F4-6.3 is STM PZ, Mirrorless Lens?
A: Macro ratio 1: 2.6. MFD 5.9 in. I bought this lens because of the pz function. I wanted to see how smooth it zoomed. I was pleasantly surprised it's extremely smooth. Power zoom can be controlled with the zoom ring on the lens, zoom rocker on the body or with the wireless Bluetooth controller I mentioned. You probably won't use this too much filming art videos, unless you are changing your field of view frequently.
So at your intended budget, my recommendations might be the Sigma 18-50 slightly above, or the Canon RF-S 14-30 slightly below your target budget. Keep in mind you should also budget for at least one additional battery or power source, one or more memory cards and a tripod.
~Rick
Bay Area - CA
~R5 C (1.1.2.1), ~R50v (1.1.1) ~RF Trinity, ~RF 100 Macro, ~RF 100~400, ~RF 100~500, ~RF 200-800 +RF 1.4x TC, BG-R10, 430EX III-RT ~DxO PhotoLab Elite ~DaVinci Resolve Studio ~ImageClass MF644Cdw/MF656Cdw ~Pixel 10 ~CarePaks Are Worth It
