Canon POWERSHOT S2 IS User Manual page 2

Use of genuine Canonaccessories is recommended.
This product is designed to achieve excellent performance when
used with genuine Canon accessories. Canon shall not be liablefor
any damage to this product and/or accidents such as fire, etc.,
caused bythe malfunction of non-genuine Canonaccessories (e.g., a
leakageand/or explosion of a battery pack). Pleasenote that this
warranty does not apply to repairs arising out of the malfunction of
non-genuine Canon accessories, although you may request such
repairs on a chargeable basis.