Was goofing around and wanted to print some abstracts w/ overemphasized grain. I figured I could focus on a very small part on the negative (35mm) to get what I was aiming for. With the head fully extended along the rails, I still wasn't able to make the image large enough to get what I wanted. What can I do to magnify this small area? Is this what extension tubes are used for? What effect would a lens for MF printing have on a 35mm negative? Thanks.