Canon EF-S lenses
Canon’s range of EF-S lenses are designed for DSLRs with smaller ‘APS-C’ sized sensors. These include the company’s most popular models, such as the EOS 400D / XTi and EOS 40D. EF-S lens optics are only corrected for use on these bodies and are not compatible with ‘APS-H’ or full-frame models.
Like all Canon lenses, you’ll still need to take your DSLR’s field reduction factor into account. Since EF-S lenses are only designed for use on APS-C bodies, the reduction factor will be 1.6 times for every model. So the general-purpose EF-S 18-55mm lens will deliver a field of view equivalent to a 28-88mm.
For a full explanation of lens specifications and examples of coverage at different focal lengths, check out our Camera Labs Lens Buyers Guide.