A small wide-angle zoom lens having good performance, in order from the object side, comprises at least a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens group G3 having a negative refractive power. During zooming from...http://www.google.co.uk/patents/US5867325?utm_source=gb-gplus-sharePatent US5867325 - Zoom lens ranging to wide angles
