Hi All, This is a followup on my original thread to get this ultrafast lens converted to Nikon mount. Here are some details and photos of this conversion. I did the conversion part yesterday took me about 5 mins plus leaving it overnight to dry out. I bought the cheap aluminium extension tubes set on eBay for Nikon F-mount. The extension tubes came in with 2 Nikon F connectors one to attach to the camera and one to the lens with 3 extension rings. All of them attach to each other using 58mm threads same as the filters. After some measurement, it appeared that only those 2 mounts need to be used - they provide just enough height for the rear lens element to be leveled with new lens mount. Since it was important to me to make the rear lens element to stick as far as possible without damaging the mirror (this is to allow as large as possible focussing distance since this lens has register of 7mm and hence won't focus at infinity) I then decided to use only those two mounts without all the extension rings. The mount that attaches to the rear of the lens was then glued to the lens back with industrial strength epoxy glue (special version of it for metal bonding) with it's extension thread facing back/up (i.e. just like it should be used with normal lens when used for it's intended purpouse). Photo here (the "other end" F-mount adapter is lying next to it): The other connector or any other extension ring or adapter (or even another lens) can then be screwed in using the 58mm thread. I simply have the second F-mount from that extension ring set screwed in directly on top of this. So it looks like this: This is how it looks on my D200 attached: A very first sample photo of the tiny 5mm metall ball made up with this lens: Contrary to my previous experience to take photos hand holding this lens - this is way much better and easier to focus now. The focus plane seems to lie somewhere around 10-20 cm in front of the lens which makes it easier to use than reversed-lens macro. I have also tried it with extension rings added like so: And it produces those magnification (photos are of the daffodil central part). 1. Taken without any extension rings 2. Taken with 20mm ring 3. Taken with all 3 rings More examples, in the followup message.