Is this normal for 28mm AIS f2.8 lens

[yinghui_zhang]

<p>I am currently using Nikon 28mm f2.8 AIS on my F3, it is really an excellent quality lens, but one thing worries me a bit, the filter thread could be rotated about 1- 2 degrees.<br /> I also have a 50mm f1.8AFD lens, but the 28mm f2.8 lens has much loose filter thread than the 50mm one.<br /> Just wondering for those who have this 28mm AIS, does yours have similar issue? Is this normal? Would it affect focusing? etc.</p>

<p>Thanks in advance.</p>

[rodeo_joe1]

<p>That's not normal. It sounds like the grub-screws that hold the front cover/filter thread to the lens body have come loose. It should be an easy fix with a jeweller's screwdriver if that's the case. It shouldn't affect focussing unless the whole helix is rotating, in which case it's a job for professional repair.</p>

[yinghui_zhang]

<p>Thanks, Rodeo. Only the filter thread rotated, the front element and other parts inside that I can see stay in their position. </p>

<p>Do not think I can fix it myself, never done anything similar. A repair manual would help?</p>

[Michael R Freeman]

<p>If the grub screws are loose, it is a simple and easy fix. Focus the lens to 0.2m and you should see 2 tiny screws on the side of the filter thread nosepiece (see photo below). The screws are very tiny and very fragile, but as long as you have a properly fitted slot screwdriver, you should be able to tighten them enough to secure the filter thread.</p>

<p>This slight rotation of the nosepiece would have no impact on the other mechanical or optical functions of the lens.</p><div></div>

[yinghui_zhang]

<p>Many thanks Michael. The picture really helps. </p>

<p>Now I can see the grub screw, but only one grub screw, as on the other side it does not has any screw, just a hole.<br>

Is this normal? I guess it would be very difficult to get a screw of such type.</p>

<p><img src="http://s32.postimg.org/yndhdmc79/IMG_9412.jpg" alt="" /></p>

<p><img src="http://s32.postimg.org/8nr8tljk5/IMG_9413.jpg" alt="" /></p>

[yinghui_zhang]

<p>Do you have any idea about the type/size of screw driver that should be used? thanks</p>

[kari_oinonen]

<p>You may get help the easy way by visiting a nearby shop selling and/or repairig eyewear or watches. They have the tools and they may have a suitable screw. The repair cost will be around nothing to 5 €/$.</p>

[yinghui_zhang]

<p>Thanks, Kari. I will do that.</p>

[yinghui_zhang]

<p>Thanks for all the input, I went to town centre this afternoon and borrowed a screw driver from the watch repair shop, and the problem solved by just fastening the screw!!<br>

Many thanks again. </p>

[Michael R Freeman]

<p>Yes, there should be two grub screws on the AiS 28/2.8, so one is missing where you see the hole. But if tightening the one screw fixed your nosepiece looseness, I would not worry about the other missing screw.</p>

<p>I'm not sure of the size, but these are specialized hardened screws with a sharply tapered cone point on one end (Nikon p/n K2-17020FB). Again, as long as you have one tightened down, I would not be concerned about the one that is missing on a small lens like the 28mm. The only purpose of the nosepiece is to provide an attachment point for a lens cap, filter or the very lightweight HN-2 lens hood. The nosepiece is fully seated and threaded on to the main lens barrel via fine pitch threads. The grub screws are only there to prevent the assembly from possibly backing out when you unscrew a filter.</p>

<p>Enjoy the lens. :)</p><div></div>

[yinghui_zhang]

Michael, many thanks for your pictures and your explanations, it really helps, and I

also learned a lot from it, really appreciated!!!

 

Using the part number you provided, I found a website which still has the screws

available, I will contact them and buy couple of these screws.

 

Here is the website

http://mikescamera.com/nikon-camera-repair-parts.html

 

Many thanks again.

[scott_murphy5]

<p>This is not normal for <em>any</em> lens. As has been mentioned, you may have a problem with the grub screws which are holding the ring in place. I suggest you take it to a qualified camera repairman and get it fixed professionally.</p>

[ziman_zdeno]

Hi Michael, please could you help me with big problem what I have? I can dissasembly everything except elements

group. I need unscrue front element from this group because there is fungus...but is impossible for me. I have used a lot

of tools but the front silver ring of this group is like as It's been glued. No holes for spanner so I'm not sure if it is right way

how to do it. Have you any idea how it could be possible? Thank you very much for you help.<div></div>