Kenko extension tubes not recognized by D300

[bhneely]

<p>I've searched the web, including photo.net for about a half hour and haven't found an answer to this problem. I have Kenko extension tubes that I use with my 50mm f/1.4 on a D300, and the camera has recently developed the problem of not recognizing that an electronic lens is attached. It automatically defaults to my most recent Non-CPU lens. The problem this creates, of course, is that I can't change the lens aperture. Admittedly, I mostly shoot at f/16 in macro, so it's not a crushing problem, but it *is* pretty frustrating.<br>

Can someone point me in a direction of what might be causing the problem and how I might solve it?<br>

Thanks.</p>

[mike_halliwell]

<p>I assume the lens is recognised just fine without the tubes?</p>

<p>I guess you have the usual set of three? Do any of them work <em>individually</em>? There may be a broken contact in one of them that cannot pass the signals through from lens to body. If you take out that tube, it should work fine with the other two.</p>

<p>Which 50mm 1.4 is it? From the fact you can't change the aperture, I'm assuming it must be the latest G variant without an A ring.</p>

[bhneely]

<p>It's the D version of the lens, so I could change the aperture manually...I'm so out of the habit of doing that, though, that I haven't tried. And yes, the lens functions completely normally on its own.<br>

And now that I think of it, it's only with one of the tubes that I have the problem. Do you know if this is fixable, or am I better off just using it as a manual lens?</p>

<p> </p>

[hans_janssen]

<p>When your aperture is closed when the lens is on the tubes on the camera there is something wrong with the aperture lever(s) of the tubes that should open the aperture to 1.4.</p>

[mike_halliwell]

<p>Whether it's a broken or mucky contact you could check with a continuity tester. There's one on every cheap multimeter. </p>

<p>Assembling and disassembling the 3 tube set in all possible different orders, ie 12>36>20 and 20>12>36 etc should 'scratch' clean all 42 connections....Give it a good clean with some IPA and see if it connects.</p>

 

<p>Looking closely at the 12mm tube in my DG set, it has 7 pins and 7 pads connected by a ribbon cable. Simples. There doesn't seem to be very much to break. There's no movement that could snap a ribbon component. I'd guess a corroded contact or maybe a separated end connection....ie ribbon>pin/pad. </p>

<p>If you disassemble the 'dead' tube you <em>may</em> find a break that's solderable. It's a bit of a pain to do though....the soldering that is:-)</p>

<p>When you say use the aperture 'manually', I assume the actual aperture blades stay open when you dial the A ring to f16 and only stop down during the taking cycle?..ie mechanically it's all fine?</p>

<p>Do you use/need all three? </p>

[CvhKaar]

<blockquote>

<p> The problem this creates, of course, is that I can't change the lens aperture</p>

<p>and</p>

<p>It's the D version of the lens, so I could change the aperture manually</p>

<p>and</p>

<p>If you disassemble the 'dead' tube you <em>may</em> find a break that's solderable</p>

</blockquote>

<p> Lleaves me puzzled...need explanation ??<br>

, D-lenses do not require anything electronic for controlling the aperture ... just like all orher "manual lenses to my knowledge... Just set the aperture on the lens for the smallest aperture on a D300..<br>

So if anything is brokrn it would be the aperture lever in (one of the three) tubes ... ( or your lesn is not set to its smallest aperture, or your camera is set to use the aperture ring for aperture control instead of the aperture dail on the camera ( which is possibelon a D300...). OR ... am i missing something ??</p>

<p> </p>

[mike_halliwell]

<p>I think the OP wants to set the Aperture from the body...No?</p>

<p>A)....If I put a dumb tube, like the PK-13, between my D300 and my 80mm 1.4D, I can set the aperture manually with the A ring and that change shows on the top LCD. When the little orange thingy is locked at min aperture, the top LCD shows f16 and can't be changed with the body controls. All as it should be.</p>

<p>B)...If I put a smart tube such as a 20mm Kenko DG, I can set the A from the body after I lock the A > f16 min</p>

<p>The OP could do B) with their tubes, but something has happened and can now only do A)</p>

<p>I think that means his Smart tubes or one, at least, have been dumbed!</p>