A friend recently let me have a go with a 105mm micro Nikkor fitted with a Nikon 4T dioptre.
After only having used a 60mm lens I was keen to see what I could do with this combination at the limit of close focus.
I came back with some pleasing images but was not exactly sure what this lens and dioptre were doing. I sensed a bit of extra magnification and a shallower depth of field but I've no idea by how much.
Apart from a + 2.9 rating can anyone explain in simple terms what you get with this dioptre?
This thread must answer must of your questions about 4T:
