Canon EOS 1Ds Mark III Optics

The Canon 1Ds Mark III will work with pretty much any EF-mount lens ever made, however it is not compatible with the special EF-S lenses designed for cameras with APS-C size sensors. Designed with a smaller image circle (the area covered by the image on the film/sensor plane), EF-S lenses tend to be smaller and lighter than full-frame models with the same focal length and maximum aperture. EF-S lenses can't be used on full-frame Canon cameras, nor on their models with 1.3x crop factors, like the EOS-1D Mark III.

The full-frame sensor on the Canon 1Ds Mark III means there is no "crop factor" for this camera, or that the "focal length multiplier" is 1x, the same as 35mm film.

I normally cite the aperture and focal length of a digital camera's lens in this part of the review, but because the 1Ds Mark III accepts a wide range of lenses, these characteristics will vary depending on the lens in use. We shot most of our test images with our very sharp Sigma 70mm f/2.8 EX DG Macro reference lens. The Far Field house shots were taken with a Canon 50mm f/1.8 Mark II.