Nikon lens + adaptor on 5DII = very, very tight fit - Is this normal?
 

I have just bought a cheap Nikon lens from eBay for use with my 5DII. It's a labelled as a NIKKOR-NC Auto 1:2.8 f = 24mm 395043. I have tried a bunch of Nikon->Canon EF adaptors bought from eBay both some of the Kawas mentioned on this forum & a couple of others from a different source that look almost identical. They all show the same problem in that while the original Canon 24-105 f4L zoom is as smooth as butter to fit or remove getting the Nikon lens on & off is a struggle & it feels like I am really forcing it. The adaptor alone fits onto the 5DII body easily & while fitting the adaptor to the Nikon lens is tight it feels more like it is fitting really firmly rather than I am actually having to force it on. There is a sort of little tongue that sits proud of the lens at the camera end (see attached photo) & I did wonder whether this was fouling something on the camera body but I have no familiarity with Nikon lenses so don't know if they all have this tongue. If it is this tongue catching would it be OK to just remove it with a Dremel? Presumambly it serves some function on a Nikon body but would be OK without on a Canon.

Cheers

Nigel

I think it may be the toungue, (or flange?) catching, i think there would be no issue in removing it and I'm pretty sure others have done the same with the older/cheaper nikon lenses. Of course I'm not sure so maybe you should wait for someone else to chime in as well...

It is probably to do with the adapter's adjustments being out. If you look close most of them have small adjustment slots on the inside ring which can be levered wider or squeezed thinner. Somehow you need to push them closer together. It's a little hard to explain but see if you see them.

Dan

It is probably the small shoulder which is cut out of the mount around the outside front flange surface. On some third party non-genuine mounts, this shoulder is not cut deep enough in either or both directions and the overhanging piece on back some of the older Nikon lens rides tight on this.

You will find that the aperture ring (iris control) is associated with this overhanging piece and it will be the iris control which may jam or be moved whenever you attempt to fit the lens to the mount.

There were different styles of lenses for the same mount. You find the suffix "AI" or "AIS" on lens model numbers. It is related to some early form of mechanical interaction with the camera internals for exposure management, possibly changing shutter speed as a reciprocal of an iris setting for the same exposure value or something like that. I don't have the knowing this stuff but a Nikon shooter would know all about it.

You may have to get a machinist to skim a little more out of this shoulder around the mount until your lens fits. It should only be a fraction of a millimetre to put it right. Don't take the Dremel to the lens. It is a most heinous thing to do, cruel even, definitely a form of abuse and you'll get all manner of metal swarf and debris into the guts of the lens and spoil it.

Thanks for the quick replies.

Dan, I found the little slots & pinching them up with a pair of pliers does make the adaptor fit more loosely on the lens so fitting & removing is much easier but that doesn't fix the problem. The adaptor fits nicely onto the lens if a little snugly & can be adjusted by pinching up or levering the 3 slots. The adaptor also attaches to the camera body smoothly on its own. Its just putting all three components together that gives the problem

Bob, I am afraid that you just confused me (not a difficult task:-). What is a 3rd party non-genuine mount? I have the genuine Nikon mount on the lens, the 3rd-party non-genuine adaptor ring with Nikon mount on one side & Canon mount on the other & then the genuine Canon mount on the camera body. The moving part from the iris ring that does protrude at the back of the lens does not protrude as much as the tongue/flange.

Nick, I think that you are most likely correct (& not just because you agree with my diagnosis:-) If I offer up the lens to the body without the adaptor then the tongue/flange does appear to protrude into the body & when I rotate it does catch inside body just above the row of sprung gold pins that carry the electrical signals between body & lens. Looking at other photos of Nikon lenses that I have found none seem to have such a large tongue/flange as this particular lens.

Cheers

Nigel

Nigel,

If you can get the lens to mount up correctly I think you will really like it. This lens was my favorite for the 20 years I owned it. Mine was the sharpest at about f 5.6. Hopefully, it will work well with your 5d.

OK, problem solved, it's the lens. Our post lady just turned up with another Nikon lens that I bought on eBay. This time a Nikkor 50mm 1:1.4. This does not have a tongue/flange/lip protruding to anything like the same degree as the 24mm lens that I tried originally. It fits the adaptor slickly & can be fitted & removed from the camera almost as smoothly as the Canon lens.

So my conclusion is that it is indeed the tongue/flange/lip that is fouling the camera body & that I have been lucky that I didn't do any damage when fitting it. So before I fit it to the camera again I need to get out my Dremel & grind off the redundant tongue/flange/lip.

Cheers

Nigel