Mirrorless users may find these other Web sites of interest. I've organized them by mount in alphabetical order (other than some generic sites I list first):
Generic:
Canon:
- Canon M forum on dpreview
- Canon RF forum on dpreview
- Jeff Cable (Canon Pro) blog
- Canon Rumors
- Canon's RF Lens Page
- Canon's Learning Page
Fujifilm:
- Fujifilm Camera Site
- Fujifilm Firmware Updates
- Fujifilm Downloadable Manuals
- Fujifilm M-Mount Adapter Lens Compatibility
- Fuji X Forums
- Fujifilm X forum on dpreview
- Fujifilm's X Photographers Gallery
- Fuji Rumors
- Fujifilm Professional Services
Hasselblad:
Leica:
- Leica forum on dpreview
- Leica Rumors
- Leica’s Web Site for SL Lenses
- List of M-mount lenses
- L-Mount Alliance
Nikon 1:
Nikon Z:
m4/3:
- Four Thirds official site (also Micro Four Thirds, or m4/3)
- 4/3 Rumors (rumor site for m4/3 equipment)
- m4/3 Blog
- m4/3 forum on dpreview
- OM Digital Firmware Updates
- Mark Young's E-M1 Mark II Setup
- Mark Young's E-M1X Setup
Sigma:
Sony:
- Sony Rumors
- Sony AlphaUniverse
- Sony Developer APIs
- Sony APS-C forum on dpreview (NEX, A5xxx, A6xxx)
- Sony full frame forum on dpreview (A1, A7, A9)
- Minolta/Sony all things Alpha site
- Using MF Lens Adapters on Sony A7 cameras
If think another Web site should be listed here, please feel free to send me that link via email.