I first purchased a right angle viewfinder about 35 years ago. When I purchased my first Nikon DSLR it was my first accessory. The DR-6 slips easily onto the rectangular eyepiece after you remove the soft factory eyecup.
The viewfinder allows me to get my camera into positions that would make it impossible to compose a shot through the traditional ways. The most obvious use has been the low level shots and it has done wonderful service there, but its articulated neck allows the user to shoot in both landscape and portrait postions on the ground and literally at an arms length above my head with the eyepiece pointed straight down.
The DR-6 has a diopter adjustment which is critical in macro (micro) work when you are in manual focus mode and a 2X power lever that magnifies the image for best focus.
I love my DR-6 because it keeps me clean, allowing me to do from squatted positions shots that would otherwise require full prone positions in the wet grass and or mud and it has saved me the pain of bent knees more often than I can count...
Review 3 for DR-6 Rectangular Right Angle Viewfinder
I find this product essential for macro work. I often need to work very low to the ground, plus the 2x magnification can really help with focusing as you approach 1:1. Easy to use, great quality, nice little case.