[Dan K] had just such a lens from Sigma, but wanted to get it working fully with a camera using the Canon EF lens fitting. Hacking ensued. The lens in question was a Sigma 15-30mm f/3.5-4.5 EX DG ...

The RF lens mount ensures compatibility with Canon's growing range of RF lenses, giving users access to quality optics for every budget and style. The R100’s Dual Pixel CMOS AF system covers up ...

Compatible with Canon, Nikon or Sony SLR cameras, this 2x teleconverter lens is made in a standard size so it will fit on many different types of camera lenses. Made with multicoated optical glass ...