Lens locked, can't change.

<p>I have a Nikon FA that has never let me down. A young nephew, I've been helping with photography was over about a week ago (<strong>he</strong> <strong>happens to be left handed</strong>) went to change lenses, and instead of turning new lens from right to top center, he went from top center to left instead. The ears are now near the self timer lever. It's now locked, and I can't remove it. Would greatly appreciate any help you can give. I'm retired and love taking film pics. with this "Old War Horse". I'll be hoping and waiting for a reply.<br /> Thanks,<br /><br /></p>

<p>Ouch.<br /> Questions: which lens is mounted now? Is it an Ai-S lens? Is the Ai coupling lever (at 2 o-clock) free of the Ai coupling ridge of the lens? Could you post a picture of what this looks like at the moment?</p>

<p>I'm trying to find out which parts of the lens could interfere with camera parts - and unfortunately, there are a couple of "extras" on the FA (the additional pin that senses an Ai-S lens just above the lens locking pin) and the lever that allows the camera to distinguish between lenses of focal length 135mm and above from those with smaller focal length (at 6 o'clock). Those are in addition to the aperture coupling lever at 9 o'clock and the already mentioned Ai coupling lever.</p>

<p>Here's an image of the Nikon FA's F-mount: http://cameragx.com/2009/10/07/5o-years-of-lens-mount-evolution-part-iv-of-vi/nikon-f-mount-3222/</p>

<p>Ouch indeed! If it is a Nikkor lens, it's usually not possible to fit the lens to the camera mount at any position other than the properly indexed position (the three flange openings on the camera mount and the corresponding flanges on the lens bayonet are different sizes). And if mounted correctly there is also a stop-screw on the lens to prevent over-rotation of the index mark past 12 o'clock.</p>

<p>If the lens was somehow mounted top to left or over-rotated past 12 o'clock and the rabbit ears are now near 8 o'clock, then it is very likely that the lens stopdown lever is <strong>under</strong> the camera stopdown lever instead of resting <strong>on top</strong> of it where it belongs. This will prevent the lens from turning clockwise to dismount. If you open the camera back and hold the shutter open on the B setting, you should be able to see if this is the case (3 o'clock when viewed from the back through the open shutter). If so, you might be able to free it with some very carefully applied sideways pressure on the lens stopdown lever.</p>

<p>Another possibility if it is an Ai/AiS Nikkor lens is that the lens speed post on the back face of the lens baffle is also on the wrong side of the sensing lever in the mirror box (visible at the 6 o'clock position in the photo of the FA mount shown in Dieter's link). That will be difficult to see from an open back, and if that has indeed happened it may also prevent the lens from turning to dismount. I hope not, because I don't know how one could ever hope to fix that problem.</p>

<p>Good luck!</p>

<p>Oops, made a mistake above - the lever in the mirror box engages the lens speed post. The distinction of focal length is done by the focal length indexing ridge (which if this wrongly mounted lens is indeed Ai-S and longer than135mm would certainly interfere with the aperture lever). Here's a link explaining all the different parts of the mount: http://www.zi.ku.dk/personal/lhhansen/photo/fmount.htm</p>

<p>The worst case scenario is that the spring loaded sensing pin on the camera body lens mount has "popped" into one of the screw heads on the back of the lens, the screws that keep the lens mount on the lens barrel. This happened to me on a N2020(F501). Fortunately it was an adapter and I was able to drill through with a fine hand drill, and with a needle push the pin in, allowing release of the adapter. My suggestion is buy an automotive feeler gauge, (multileaved) and try to wiggle the feeler gauge between the lens mount and the spring pin allowing you to rotate the lens in order to remove it from the camera. Good luck, hope you are successful otherwise a technician's skill may have to solve the problem.</p>

<blockquote>

<p>The worst case scenario is that the spring loaded sensing pin...</p>

</blockquote>

<p>That's a possible scenario but not the worst case IMO. Michael mentioned what I consider the worst case scenario - which is that the lens speed post on the lens (if Ai-S) is now behind the feeler in the camera's mirror box as there likely isn't an easy way to get that one resolved without sacrificing the lens. But there is the hope that the lens isn't Ai-S. In which case, the the aperture lever and the Ai-S sensing pin are the ones to worry about - as well as getting the Ai-ridge on the lens passed the Ai-lever without damage.</p>

<p>This is more of knowing which camera brand turns lenses clock-wise, and which camera brand uses counter-clock wise movement. Being left-handed person is not an excuse.</p>

<p> </p>

As Dieter points out, it is best if the OP could post an image showing how the lens is stuck.

<p>There is supposed to be a little screw inside the lens flange that prevents reverse rotation. If that screw is missing, you can turn it the wrong way, and at least in the case of old F's and the like, what happens is that the aperture lever in the camera gets on the wrong side of the aperture lever of the lens. It might be possible to open the shutter (F or B with a locking cable release) and work the levers around each other with minimal bending. On the F, the camera's lever is brass, and if bent a little it can be bent back. I don't know about other cameras, and would be inclined to take it somewhere.</p>

<p>It's not a bad idea every once in a while to check your lenses and make sure those little screws are still there. They do fall out occasionally. The pertinent screw is a tiny one, under one of the flange ears of the lens, 180 degrees from the top red dot. </p>

Sorry, I was "out of pocket" got back this am. First you guys are amazing, you got on this so quickly. I appreciate your effort. On the left side the "rabbit ears" are at about 8 o'clock. Anything you need from me, just ask.

 

Thanks<div></div>

<p>First - this is an Ai-S lens - which makes this about the worst one that could have been stuck on an FA the wrong way because there are a maximum of levers that are now on the wrong site of their in-camera counterparts and might cause trouble moving the lens back. Here's an image of the back of this lens: http://www.amazon.com/Quantaray-28-80mm-3-5-4-5-macro-manual/dp/tech-data/B004LZP0Q4%3FSubscriptionId%3DAKIAJQUI3TELYD5FOFTA%26tag%3Dblaznewelectonic-20%26linkCode%3Dxm2%26camp%3D2025%26creative%3D386001%26creativeASIN%3DB004LZP0Q4<br /> (the image also shows the little brass screw that Matthew mentioned above (just above the N/AI engraving in the mount) - the fact that reverse rotation was even possible seems to indicate that the screw is missing though)</p>

<p>I am surprised that the lens actually got on at all and that it was possible to turn it that far. I would expect that some force must have been necessary to accomplish this? First to mount it with the rabbit ears up, I suspect that the Ai coupling tab (2 o'clock) had to be pushed in (similar to mounting an non-Ai lens) - so chances are that that part on the camera has already sustained damage. Maybe if the lens was fully stopped down, the ridge might have just cleared the Ai tab (certainly worthwhile to set the lens to fully closed when attempting a dismount).</p>

<p>While it might be possible to get the aperture tab past the actuation lever in the camera by working through the back, I doubt the same is possible for the lens speed post (though I am curious how it moved past the in-camera lever during mounting). Maybe the lens was attached so that the post on the lens just cleared the in-camera part (on the "wrong" side of course) - and thus should not interfere with the dismounting operation either. Considering how sturdy the post is and the in-camera counterpart - this seems to be very likely (which is good news).</p>

<p>Question: does the lens move at all (make sure you push the lens release on the camera as the corresponding locking pin might have snagged in one of the lens' screw holes)? Also, as already mentioned above, you need to use a feeler gauge to push the Ai-S sensing pin down - as it might also have gotten stuck in a screw (or will do so when the lens is turned). That screw near the N/AI engraving appears to be just in the right position for being the culprit that prevents the lens from turning at all (or at least not very far).</p>

<p>I am very much afraid that there isn't going to be an easy way to get the lens off - for certain the aperture tab and the sensing pin will need attention during an attempt to dismount the lens.</p>

<p>Another option might be to disassemble (and possible sacrifice) the lens - but coming from the "wrong" side this might not work and might entail drilling out the lens mount screws.</p>

<p>Time to get a new nephew! Only kidding...</p>

<p>I have been playing with the lens and camera and have noticed that if you point the rabbit ears down toward the bottom of the mount that the lens will almost go all of the way in to the camera mount. A person not experienced with the F mount might have tried to mount to the lens from the indexing side of other brand cameras, and forced it into the mount in frustration, turned it clockwise with a fair amount of force and succeeded. It is probably damaged already. You may need to turn it back ccw to dislodge it. Good Luck!</p>

<p>William brings up a good point - so far I've assumed (as suggested by the original post) that the lens was mounted with the rabbit ears at 12 o'clock and forced into the mount in a CCW rotation with the rabbit ears ending up in the current 8 o'clock position. Was this indeed the case? If so, it would imply that a CW rotation should be applied to remove it.</p>

<p>If, however, the lens was mounted with the rabbit ears in a 6 o'clock position and turned CW into the current 8 o'clock one - then a CCW would be required to dismount it.</p>

<p>Hence the question to the OP - how certain are you about the way your nephew mounted the lens?</p>

<p>Needless to say there's a limit to how many different ways I'll try to mismount a lens on any of my Nikons, but a little experimenting suggests that at least with an F, one cannot mount the lens any but the right way if the screw I mentioned above is in place. I did not remove that screw to see what would happen then, but if this were my camera, the first thing I'd do is open the shutter and look at the mounting from the inside to see what might be in the way and what might already be bent.</p>

<p>If you would open the back and hold the shutter open it might be possible to see the actual damage and possibly the direction of turning.</p>