I have a DaYi 6x17 back for a 4x5 camera. I paid $500 for it a few years ago. I'll sell it for the same, and throw in the PayPal and shipping fees. Still in excellent condition. Works well with lenses up to 180mm. You will of course need a 4x5 camera with a universal back (graflok). The nice thing about using the back over a dedicated camera is you can use movements.