The Samyang 85mm f/1.2 lens is priced at £899, and is available in Canon EF fit only. The only competition is from Canon themselves, with the EF 85mm f/1.2L II USM at £1649.
The amount of selective focus possible with a wide aperture 85mm lens helps anyway and the overall effect is very pleasing. This will be very useful for beautiful portraits, which is one of the ...
The Sigma SD1 is sold body-only, or bundled with one of three Sigma lenses: the 17-50mm f/2.8 EX DC OS zoom, 30mm f/1.4mm EX DG HSM prime, or 85mm EX ... so be aware of sample variation.