The Canon EOS R is a full frame mirrorless camera that uses the RF lens mount, while the Canon EOS 90D is a crop sensor DSLR that uses the EF and EF-S mount. In short, choose the EOS R if you want full frame image quality and a modern mirrorless system, and choose the 90D if you want a traditional DSLR with extra reach from a smaller sensor. Confirm exact specifications on Canon’s pages before buying.
Two Different Kinds of Camera
These bodies come from different eras of Canon’s lineup. The EOS R was the first body in the RF system, built around an electronic viewfinder and a full frame sensor. The 90D is a late model in the long running APS-C DSLR line, built around an optical viewfinder and the mature EF-S lens range.
Key Differences
| Trait | Canon EOS R | Canon EOS 90D |
|---|---|---|
| Body type | Mirrorless | DSLR |
| Sensor size | Full frame | APS-C (crop) |
| Viewfinder | Electronic | Optical |
| Lens mount | RF | EF and EF-S |
Sensor size shapes the look of your photos. A full frame sensor generally gives shallower depth of field at the same framing and aperture, and it usually handles dim light more gracefully. A crop sensor effectively narrows the field of view, which can make a telephoto lens feel longer for birds, sports, and distant subjects.
Lenses and Adapters
Lens choice often decides this comparison. The EOS R uses RF glass natively and can use older EF lenses through Canon’s mount adapter. The 90D uses EF and EF-S lenses directly, and these are plentiful on the used market. If you already own EF lenses, the 90D needs nothing extra, while the EOS R needs an adapter but gives you a path into the RF line.
How to Choose
- Write down what you shoot most. Landscapes, portraits, and low light favor full frame. Wildlife and sports at a distance favor the extra reach of a crop body.
- Count the lenses you own. Existing EF-S lenses will not cover the full frame area of the EOS R in a useful way.
- Decide on viewfinder preference. An electronic finder shows exposure before you shoot, while an optical finder shows the scene directly with no lag.
- Think about the future. Canon’s current development is focused on RF, so the EOS R points toward where new lenses are headed.
FAQ
Can I use EF lenses on the Canon EOS R?
Yes, with Canon’s EF to RF mount adapter. Confirm compatibility for your specific lens on Canon’s support pages.
Is full frame always better than crop?
No. Full frame offers wider coverage and shallower depth of field, but a crop body can be lighter to carry with a long lens and often costs less to build a kit around.
The Short Version
Choose the Canon EOS R if you want full frame files, a mirrorless viewfinder, and a mount with a future. Choose the Canon EOS 90D if you already own EF lenses or want extra reach for distant subjects. We have not used either camera ourselves, so check Canon’s pages for current details.
