My understanding is that, as a diopter it doesn't really amplify, but allows you to focus closer with an existing lens. In my experience, the focal distance and depth of field will vary with the lens. I use a .2 diopter with my 18-200 lens that allows me to focus within 8 inches of the lens at 200mm. This allows a substantial "amplification", but the depth of field becomes less than an inch, making for a very touchy focus. Backscatter rates the macro mate at 3:2 using a 105 micro, I believe. I have little reason to doubt that, though I haven't tried it. The sample images in their gallery make it look quite reasonable. I think the quality of the image is more important than the actual increase in image size, as you can gain that through cropping. The main advantage would be less water column between camera and image, giving you the clarity of proximity of perhaps a 60mm micro with the greater magnification of the 105 at that distance. I think the test would be to shoot the 105 at the focal distance obtained with the diopter and check the size of the image compared to the normal minimum focal distance, regardless of whether it is in focus. So the question might be, "what is the minimum focus distance of the Nikkor micro 105mm lens with the macro mate installed?"