Thanks for the informed replies guys. Much appreciated. Just as I suspected but interesting to understand the reason why. It's a shame as I like my Canon zoom and it was expensive so not sure how good a price I'd get 2nd hand. I'll wait til I get that dream Nikon before deciding whether to sell my Canon gear or keep it as a cheaper travel model when I don't need low light capability. Hope to buy 2 or 3 Nikon lenses when I can but I'll save that for another thread.

It has to do with the flange distance. Nikon can go to Canon, but not vice versa.

Following is a comment posted on another site, not by me, so I cannot claim whether this is correct, though it sounds correct. The other site is (this link might be removed, im not sure if this goes against site policy..?) http://the-gadgeteer.com/2010/07/26/pair-up-a-nikon-lens-with-a-canon-camera-or-vice-versa/

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Systems with larger “flange” distances (e.g. Nikon, Olympus OM, etc.) are “universal donors.” i.e. their lenses can be used (in manual mode) with more camera systems with relatively simple physical adapters, but their bodies can only take relatively few lenses.

Systems with shorter flange distances (i.e. Canon, FourThirds) are “univeral acceptors.” I.e. their bodies can take more lenses with simple adapters, but their lenses are relatively limited in use.

The newer “EVIL” cameras (i.e. Electronic viewfinder, interchangeable lens) such as µ4/3 and similar models from Sony and Samsung are noted for having much shorter flange distances and can use almost any SLR lens with appropriate adapter.

Nikon lens + Canon Body is easy. The reverse, less so.

It is possible to create an adapter to allow the use of shorter flange lenses with longer flange bodies, but doing so introduces compromises. A simple adapter would likely lose the ability to focus the lens at infinity. The lens, with sufficient manual controls, would work fine as a macro lens in that case as the adapter/camera would basically act as an extension tube.

It may be possible to create an adapter that adds optical elements to correct for the flange differential, but those would either be expensive or compromise quality. For example, Canon made some of those for adapting their old FD lenses to the EF bodies.

I could be wrong here but I thought the only reason that Canon users could use Nikon lenses with an adaptor is because the Canon camera has more space between the digital sensor and lens mount than Nikon, or the difference between the way a Canon lens and a Nikon lens displays the image on the sensor. Therefore they were able to make an adaptor that could mesh between the two and make it a usable lens on the Canon. Unfortunately you can't go the other way, if that is the case.

I thought I read that somewhere but with my oldtimers who knows where that was, of course I do know it came from the internet so take it with a grain of salt.

If they exist Novoflex would have the best ones. Realistically you would be much better off swapping lenses to Nikon than using adapters.

I'm new here. Currently waiting to change over from Canon to Nikon gear. Waiting for the true D700 low-light replacement so I might have a bit of a wait yet! This may well be a silly question but...I've noticed there's several adaptors around for using Canon or other lenses on a Nikon body but can't find any for the other way around. Am I correct in thinking no Canon EF to Nikon F Mount Adaptor exists? I have a very decent Canon EF 70-300mm f4.5-5.6 DO IS USM zoom lens. It's a very compact quality zoom for 300mm so easily portable. It'd be useful to be able to use it on a Nikon body, even if only on manual.