Dwig mentions extension tubes and EF-S lenses. Actually, not "all" extension tubes will accommodate EF-S lenses. In fact, the earlier electronically fitted extension tubes from Kenko and Soligar will NOT accept the EF-S macro lens or the EF-S zoom lenses from Canon.
Kenko AF extension tubes (also branded and sold as Soligar in parts of the world) which have the small, white SQUARE mounting index are the newer, EF-S compatible tubes. The small, white SQUARE lens mounting index is the clue that a body, lens, or accessory is EF-S compliant. Any Canon-mount product with a round RED DOT index point means the item is intended only for use with EF mount accessories.
Using an EF-S compatible extension tube will allow an EF-S lens to be used with an EF Canon body; as Dwig mentioned, the newer EF-S compliant automatic extension tubes have what would be called EF flanges on the rear, but the front of the tubes will accommodate the deeper-seated EF-S lenses.