Useful bit of kit...

when added to my 55-300mm zoom it practically turns it into a useful 600mm...not quite of course but for most uses, it's virtually as good. I spotted it brand new in the then Jessops shop in Blackpool, around 30 years ago and even back then it had all the electrical contacts for focus and aperture fitted. The amazing thing was, I found it didn't degrade the quality of the Nikon lens in any detectable way I could spot and at less than 30 quid, proved a real bargain:)