Hey, I'm using a Cambo Wide DS with a 65mm lens and 4x5" revolving back ( http://www.cambo.com/Html/products_photo/set01/english/internet/Item21915.html ). But for some reason I am unable to focus and all seems unsharp when focussing, am I missing something here? It cannot be used in combination with the 65mm lens? I use a grid glass to focus without any issues on my older Cambo (580 and 750) series. Thanks.