I have a few old documents that are A3 and larger that I would like to digitize. I don't have a flatbed scanner of that size. I am thinking of taking photos of them instead and just use the JPEG. My problem is: how to set it up for the shots? I was thinking of using a ladder and shooting vertically down. But not sure how to hold the camera in place. If I shoot with a tripod, I don't know how to hold the document perfectly perpendicular to the ground. Any suggestion for a simple DIY setup that I can use to shoot?