Sigma has come out with a fast telephoto lens that works with the Canon EF mount system. This lens is a prime lens at 135mm and has an aperture range of F/1.9 to F/16. B&H has this for sale at $1,399. Some ideal uses for this lens will be portrait and studio photography. To buy this lens: https://www.bhphotovideo.com/c/product/1321303-REG/sigma_135mm_f_1_8_dg_hsm.html