I'm not 100% certain if this will make sense. But I'll give it a shot. What's the purpose of buying a $1,000 macro lens when you can buy these Tiffen (and other brands) +7 and +10 screw on lenses for $40-$70? I'm looking for a cheap way to get in there close on small bugs and other micro things. The lenses I'm going to buy with my Nikon D50 are the 18-55mm ED AF-S F/3.5-5.6 and the 70-300mm ED AF F/4-5.6. I also need to know what size (mm) ring to buy if I deside to buy one of these tiffin +7's or +10's. As you can tell this is all new to me. I'm sure buying the $1,000 macro lens produces better images but are the screw on lenses a good alternative for someone, like me, on a small budget? I've seen some awesome photos from a website that was using a Tiffin +10. All advise welcomed?