Many recent lenses for mirrorless cameras rely heavily on in-camera correction for distortion. As you’ll see from this graph, using distortion data for prime lenses as well as for zoom lenses at their shortest focal length (where distortion is typically worst), the Canon RF 16mm and RF 24-105mm lenses are unusable without automatic correction. Indeed, the in-camera distortion correction option can’t be switched off. Even so, the 7Artisans 50mm and Canon RF 35mm mirrorless primes are the closest to being zero-distortion lenses.