An APS-C lens may mount yet cover a smaller recording area. Canon specifies automatic cropping for the RF-S18-45mm on supported full-frame EOS R bodies.
Make the exact-model decision
Check your exact body and lens together; do not assume all brands crop the same way. Record the body’s sensor area, lens image-circle designation and exact still/movie mode. Check each focus and stabilization function separately.
A manufacturer example
Canon identifies the RF-S18-45mm as a 49 mm-filter APS-C lens and describes automatic APS-C cropping on compatible full-frame EOS R cameras. Use the linked page for its stated model and revision; a different model may need a different support document.
Where to draw the line
Crop mode narrows the recorded view without changing the focal length printed on the lens. A still-AF statement may say nothing about movie AF. If a source does not address the exact feature you need, record that feature as unknown rather than treating silence as support or incompatibility.
Your next step
Take the model code from the body or lens label, open the official source below, and compare its scope with the equipment you have. Then use the test an exact pair to organize what is known. Do not mount an item that resists or appears on a maker’s exclusion list.
Official sources and scope
Checked for this reference on October 30, 2026. Product firmware and support lists can change; inspect the current maker page for your exact revision.