What To Upgrade (and Downsize) From Canon 80D?
I have an 80D with 4 varied lenses. I am happy with it, but I really want something smaller. Some things I am considering:
1 - Purchasing the SL3 as a second camera, so I can use all my lenses
2 - Getting a mirrorless for about the same $, with an adapter
3 - Trading in the 80D for a full frame mirrorless, like the EOS RP
I want the ability to shoot HD video as well.
Wow! What a great question, Steve.
You do have several options when considering upgrading and downsizing your Canon 80D to either mirrorless or a super small DSLR.
Downsizing from 80D to SL 3
I'll start by recommending that you eliminate the Canon SL3 from your options. You'll only save about 10 oz. in weight by downsizing from a 80D to a Canon SL3, so that's not a big deal. Even though you're talking about it as a backup, I don't think you'd be happy with its performance if you're used to your Canon 80D. I'm assuming you're a guy with an average sized hand-I don't think you'd like the grip on the SL3 either.
Upgrading to Mirrorless From Canon 80D
Unfortunately, the size advantage when switching to mirrorless is reduced somewhat when you add an adapter and a full frame lens. Some photographers would rather go for a smaller APS-C camera and the smallish EF-S lenses that will keep the size and weight down. It does depend somewhat on the mix of EF Vs EF-S
Lenses you have. (I went from a 70D to a 90D because of the higher megapixel count, the updated Digic processor, and the dramatically improved video capabilities. I'm not sure that upgrading from your 80D to a 90D is enough of an upgrade to justify the investment.)
Replacing Canon 80D With EOS RP
I like the EOS RP a lot and seriously considered it myself when I was upgrading from my 70D. It's about the same weight reduction as the SL3, BUT it's also an upgrade to a full frame sensor.
Canon has been behind in their mirrorless offerings (especially compared to Sony) but the EOS RP release in early 2019 changed the game a bit. It's definitely a great opportunity to enter into full frame and mirrorless at an attractive price point, although the RP is a mid-level performance camera.
A big part of going from an APS-C camera like the 80D to a full frame DSLR or mirrorless is the lenses you have and the lenses you're willing to purchase. I don't know what you like to shoot or the specific Canon lenses you have, so it's hard for me to get real detailed with my answer on an 80D replacement, but I hope this helped give you some ideas, Steve.
Please let me (and other readers) know what direction you take. Just curious if you'd consider a high end compact like the Canon PowerShot G1 X Mark III as your backup to your 80D. It does have some limitations for sure, but it's got an APS-C sensor, a viewfinder, shoots raw, and its size is amazingly small-it fits in your pocket-compared to your 80D.
Thanks so much,