Help with Nikon Lens Diagnosis & Repair

<p>I've been shooting with my Nikon 300 f/4 D ED-IF AF-S and Nikon TC-14E II on my D90 since I purchased them new in June 2011 from Amazon. Lately, the lens will not focus at all on distance objects. I sometimes hear the motor try and engage, but then nothing. I have to manually focus and then the AF-S locks-in. Close focus seems to be fine so far. Can anyone give me an idea on what the problem might be, how long it will take to repair, and how much it might cost? I appreciate it!</p>

<p>Well if the lens is only a year old, and if it's an official nikon-usa import, I believe the warranty is 5 years.</p>

<p>Edit: If you dropped or damaged it, send it in to Nikon for a "free estimate".</p>

<p> </p>

<p>Easy things first: clean contacts, play with the AF-limit switch, and test other lenses and/or other camera.<br>

When you focus manually, is there a point of increased resistance. Play with manual focus ring a couple of times from limit to limit.<br>

And of course, test without TC too.</p>

I don't have my 300mm/f4 AF-S with me, but I don't recall that it has a focus-limit swich that limits it to close focusing.

Therefore, this is probably a mechanical problem, but please take that comment with a grain of salt since it is difficult to

diagnose a lens remotely without physical access.

 

If it was purchased from amazon.com in the US last year, as Bob suggests, it should be under Nikon-USA's 5-year

extended warranty. I have read complaints that Nikon USA frequently blames things on "impact damage" and decline

warranty repair. Hopefully your lens hasn't had any of that.

<p>Just a guess here: you have had the lens and tele-converter since June 2011. If there is a issue with either, the Nikon warranty (as noted above) should apply. If you have had your Nikon D90 a couple of years, it may be that the focus-motor may be your problem. The D90, a fine camera, is not quite the heavy-duty body that, for example, a Nikon D3 is. If you get in touch with Nikon (via e-mail is free) you can find out how long a check-up or repair might take.</p>

<p> </p>

<blockquote>

<p><em>"If you have had your Nikon D90 a couple of years, it may be that the focus-motor may be your problem. The D90, a fine camera, is not quite the heavy-duty body..."</em></p>

</blockquote>

<p>The lens in question is AF-S, so doesn't use the D90 in-camera focus motor.</p>

<p>If the problem only occurs near infinity and "corrects" by moving the focus manually, I would be inclined to believe the problem lies with the silent wave motor in the lens. The teleconverter essential serves as a "pass through" communication device with respect to focusing, and the camera body autofocus module doesn't really know the difference between an object at 10ft or an object at infinity when finding focus. It only knows that it needs to move the lens elements in a particular direction to get the image is in focus.</p>

<p>Best bet is to contact Nikon service, although I expect they will suggest that you send in all three pieces for inspection. As others have noted, this should be covered under warranty if these are official imports.</p>

<p>Slightly off topic, but do Nikon's modern teleconverters really act as a simple "pass through" for the primary lens connections? Or does the TC intercept the signals to automatically correct the reported focal length and aperture? Just curious about this since I only have older MF Nikon TCs.</p>

<p>My reference to simple "pass through" communication was with respect to autofocus function only, since the teleconverter would simply pass the signal from the body through to the lens SWM to autofocus the lens.</p>

<p>With <strong>some</strong> lenses I think the 'E' converters do report correct effective focal length and aperture in the meta data. But on some they do not. I have a modified TC-14E, and when mounted on an AF 80~200/2.8D (a lens Nikon never intended it to be used with) it does not report the effective focal length or aperture. The meta data (and camera displays) report the master lens values for the combo. But that lens only has 5 CPU contacts, so that might have something to do with it. I have also read that on some combinations it will report a focal length different from the master lens, but an incorrect effective focal length.</p>

<p>I've had the same with my AF-S 300 f/4 on a D300. In the "field" I could solve it with mounting the lens again. Afterwards, I cleaned the contacts, and it was fine again, did not notice it again (but I haven't used the lens a great deal lately).<br>

I had the problem mainly without the TC - with TC it worked fine, but the connection between TC and lens seems a bit tighter than lens to camera - so maybe a case of being on the border of tolerances?</p>

<p>Thanks to all for your help! </p>