I don't have an 85mm prime, but I have a 90mm macro lens.
90mm + raynox
13cm away (at 1:max) - max F32
11cm away (at 1:10) - max F36
8cm away (at 1:3) - max F45
5cm away (at 1:1) - max F64
18-105mm + raynox @ 105mm
12.5cm away (at infinity) - max F36
8cm away (at 0m) - max F36 - lots of vignetting
18-105mm + raynox @ 50mm
12.5cm away (at infinity) - max F32
50mm + raynox
11.5cm away (at infinity)
11cm away (at 1.5m)
9.5 cm away (at 0.7m)
8.5 cm away (at 0.45m)