My dropped D300s with Sigma Lens coincidence.

<p>A few weeks ago I shot a concert using my two D300s bodies, Tamron 17-50mm f/2.8 VC and Sigma 50-150mm f/2.8 OS (the best lens I've ever used). With the cramped space in the wings, I dropped the camera with the 50-150 on the floor. "Oh CRAP!!!, did I damage it?" I did a few quick tests and all seemed to fine. I use the 50-150 mainly to get tight shots of the conductor from the wings or behind the orchestra.</p>

<p>Sunday night I shot another of their concerts and the conductor asked me to get some shots from the balcony. To get the best framing, I needed to use 50mm on the 50-150, but I discovered it would not focus, neither auto nor manual. I zoomed in a little and found that it would focus from about 100mm to 150mm. I was able to get most the shots I needed, but I was bummed to realize that I really had damaged something.</p>

<p>Monday morning I looked over the lens as best as I could, checked all the AF/manual settings, and found that the lens had real difficulty mounting and unmounting. I figured I must have bent the flanges on the lens and maybe the camera too. But when I put the Tamron on that camera, it worked fine. In trying to put the 50-150 in my other D300s body, it would not mount at all. So I got out my fairly new Sigma 120-300 f/2.8 to verify that the mount on the camera was OK, but discovered that 120-300 would not focus at all. Now I have two messed up lenses.</p>

<p>I took them over to Samys Camera near me since they're a Sigma dealer. They were about to send them both to Sigma in New York when I asked to mount the 50-150 one more time on another camera, but it would not mount on the D7000 he brought out. He inspected the lens carefully and discovered that the screws on the mount were loose. When he tightened them, the lens worked perfectly. The 120-300 though, would not focus at all, but at least it's still under warranty.</p>

<p>I was so relieved that the 50-150 was a simple fix, and I have to say, if not for that problem, I would never have tried the 120-300 and might have discovered it didn't work only when I used it for a job. So it's on it's way to Sigma.</p>

<p>I'm surprised the screws loosened on impact enough to prevent mounting, but weren't stripped so much to prevent re-tightening. I wonder if they were a tad loose to start with and shook loos<strong>ER </strong>on hitting the deck? I guess the floor was carpet over wooden floor-boards? Kinda springy.</p>

<p>I'm eyeing up a 50-150mm OS to mount on the not-yet-released D7200 as a lighter-weight D700 + 70-200mm VRII combo. If they get the buffer right, there are jobs where I don't need 8fps....but shoot a lot of bursts. I guess a High-Speed card could mitigate the buffer somewhat.</p>

<p>When the 120-300mm 'refused' to AF what were the symptoms? Just nothing happened...like no motor? As if the AF/MF switch was locked on MF?</p>

<p>I would be testing the D300 to make sure it is not the problem.. I would bet that if the camera and lens hit hard enough to loosen the screws on the lens then it may have shifted the mount on the camera. If the camera lens mount is not square with the film plain then the images will not be focused correctly on the film plain.</p>

<p>Looks like a Mike fest.</p>

<p>Halliwell - The 120-300 was as you said, no motor on AF. I sent it to Sigma.</p>

<p>Bradtke - I tested the camera with three other lenses and the tightened 50-150 and there are no discernible problems.</p>