I have been reading about free lensing and I realised I had all the things I needed.
1/ A digital dSLR camera
2/ An old lens that can be dismantled
3/ A pair of hands.
First I took apart the old lens. It was a 50mm f1.8 Zuiko lens off my old Olympus system. The lens was in a bad condition and I had another so it was stripped back as far as I could. I had intended to leave the aperture mechanism intact unfortunately due a bit of over enthusiasm and the removal of some important screws the aperture blades cam loose and ended up removed. In the end not a problem as I wanted to shoot wide open anyway.
I was finally left with a very compact unit containing only the glass lenses in a plastic unit.
The lens is just held in front of the camera, in my hand, and moved around until the picture looks right through the lens. there is vignetting and light leaks but that is the fun of the images.