Nikon has announced it is suing Sigma for infringing two of its patents relating to image stabilized lenses. The company says it had attempted to negotiate a resolution but concluded 'filing a lawsuit was the only way it could protect its intellectual property.' Japanese website DCWatch is reporting the disagreement as relating to Japanese patents
3,755,609 and 3,269,223, which cover 'zoom lens that can shift the image' and equipment 'provided with an ultrasonic motor and vibration detector,' respectively. News agency Reuters reports Nikon as seeking around 12.6 billion Yen ($154m). Due to the ongoing legal process, Sigma declined to comment.