My i-pad has photos from i-photo, cant delete them with Yosemite photos

My i-pad has all its albums and photos copied from my old mac (Snow Leopard) I-Photo. I have changed my Mac for a new one (Yosemite) with the photo app. I now find I can't delete or manage any of the images on the i-pad. Any ideas on how I can wipe the photos from the ipad and start again?