Can you ID part on D5100?

fishwrapper

New member
Can you tell me what the prong/tab projecting from the body immediately alongside the lens mount is? It would be at about the 8 o'clock position as you face the lens mount. I cannot find any info in the camera manual and so far nothing back from Nikon. I have several older lenses, Nikon E Series, and a few Tamron adaptall lenses which all work fine on the D5100 in fully manual mode. Except that the rotating tab on the back side of the aperture ring contacts this protruding tab on the body as the lens is stopped down. I cannot quite reach the smallest apertures on these manual lenses because of this
issue.

There is a ramped/angled edge on this springloaded/retractable tab, as though something should slide onto it, pushing it back into the body, but these old lenses have square, sharp edges contacting the tab. Bumping into it is starting to mark the edge of the tab. All the literature I have read says that these lenses should mount and function manually....no mention of any mechanical issues. What is this tab supposed to do?

The two kit lenses I have, AFS 18-55 VR and AFS 55-200, of course have no aperture rings and don't contact the tab in any way.:confused:
 

SkvLTD

Senior Member
I know what you're talking about, no idea what it does either, but I have an old Nikkor-H 50 pre-AI and that springy pinky doesn't get in the way of anything. Sounds quite odd.
 

fotojack

Senior Member
Is there any way for you to take a picture of what you want to know about? It'll make it easier for us to determine what it is you're asking about.
 

SkvLTD

Senior Member
Just look at your D5100, Trac. Its a little spring-loaded peg that sits right outside the mount on the body at about 8 o clock as OP said if you looking at the front of the cam.

Aperture rings, at least on Nikkors, never protruded past that little peg from what I gather, but I suppose other brands may have. Nikkors' casing edges sit flush between the outer wall of the mounting ring and that springy peg.
 

fishwrapper

New member
First, thanks for the responses. Nothing yet from inquiry I sent to Nikon as to what this gizmo does/is. That is the real question for me, since I don't know at this point what I might be damaging, if anything. Can't find any pic or reference in the manual.

SkvLTD, you may have answer to why I am the only one with this issue. I have no true Nikkor lenses except the AFS lenses mentioned above which of course have no aperture ring, and I am told that the Series E types are not true Nikkor either. So if I am understanding you, nothing on your Nikkor-H is outside the lens mount as the ap ring rotates?

tracsoft and fotojack; I can try to get a photo on here if it will help. Is there a page on the site for us who are still struggling with how to work on this forum? (I still have not been able to enter photo gear as requested in welcome message.)
 
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