Dropped lens

<p>While changing a lens, I dropped the Sumicron 75 f/2.0 about 6 to 8 inches onto a wooden table. It landed on the front edge of the barrel. The lens appears o.k. -- the aperature works correctly when the ring is turned and there is no sticking or roughness when the focus ring is turned. What other damage is possible that I can look for or not? (I worry that the coating might flake or the cement might crack --something like that.)</p>

<p>IMHO you lucked out probably a non event. Are the filter threads still unharmed? A friend dropped my 90mm f2.8 Leicaflex lens onto a metal table about 8 inch drop, no effect. These Leitz lenses were made for professional use and can take it!</p>

<p>I'd worry more about the table. Leica lenses, mechanically, are pretty simple and very sturdy. If the fall didn't even damage the filter thread then I wouldn't worry too much.</p>

<p>Shoot a roll of film to see if anything has been knocked out of whack.</p>

<p>I dropped my Summicron 35/2 on the subway once (I had accidentaly tripped the lens release button whilst squeezing my way through a crowd, or so I beleive). The mount was slightly scuffed, but the lens still works a charm, if you can't see any damage looking through the lens or feel any irregularities when working the focus/aperture I dare say your lens is damage free. </p>

<p>6 to 8 inches is not much, particularly with a wooden surface. If it dropped in a non vertical line, a part of the impact would have been transfered into some rotation and that would lessen the effect. I dropped my Summicron from a three foot height onto a gravel path in the Smokies, and apart from a small bright spot on the focusing ring, the lens was perfectly OK afterwards. I dropped an M3 onto a wooden floor from shoulder height and had to replace the VF prism (cement separation), but the rest of the camera was unaffected and required no readjustment (which I had done, but was told it was in perfect shape).</p>

<p>Although it doesn't sound like it from my experience over 20 years, I take quite good care of my equipment. I wouldn't worry about your lens, but you can always shoot some detailed far, medium and long distance photos of detailed subjects (fine, bare, tree branches, centre and edge of the frame) if you are worried.</p>

<p>First off, the term "rangefinder" is not to be interpreted in a military sense: find the range to the target, then fire a gun or drop a bomb...</p>

<p>Now, that aside, it's surprisingly easy for a hard hit (drop onto a surface with no give) to decenter an element. (it's harder to delaminate or break the adhesive bonds that hold elements together).</p>

<p>To check centration, you have to do a really good job of aligning the camera parallel to something flat and detailed. Load up some fine grain (preferably B&W) film. Focus on the flat, detailed surface, back the focus off a bit in the near direction (about 1mm of rotation) and shoot it wide open, Move 0.5mm towards the correct focus point, shoot again. Move to teh correct focus point, and shoot again. Keep this up until you have a set of 5 shots: 1mm too near, 0.5mm too near, in focus, 0.5mm too far, 1mm too far. Develop the film promptly, and check the corners on each frame with at least a 10x loupe. If all four corners are equally in focus (or out of focus, depending on if you're a glass half full kind of person or not) in each frame, you're fine. And, if the center is in the best focus in the middle frame, congratulations, your rangefinder is on. If the center and corners are all at their best in the middle frame, congratulations again, you have a sample of the 75mm that has a reasonably flat field (yeah, you wish).</p>

<p>Bruce, I agree with Paul and the others. I recently dropped my new Zeiss 50mm Sonnar C about 1.4m onto a hard wooden floor. It looked, sounded, felt and worked fine. Pictures since then all OK. When I had recovered a little I saw some serrations in the floor where it had dropped and it had clearly landed on the filter (B & W, brass) which had a slight deviation in the anterior lip. Thread worked perfectly still and the hood went on OK. Just can't add a filter. I think the filter helped save the lens. You'll be fine.</p>

<p>It's most likely just fine. Use it and look at the results, if acceptable, forget about it.<br />Mechanical robustness is one of the reasons for purchashing professional equipment. I have banged and dented all manner of both Nikon SLR and Leica equipment over the years with never a trip to the repair shop. Last year I dropped an M7 with 21mm f2.8 ASPH attached about 6 inches onto a wooden table. The lens had the hood on at the time and the hood impacted the table first. The only thing I could find wrong was a dent in the wooden table. M7 and lens work just fine with no cosmetic damage.-Dick</p>

<p>Everything seems fine the filters still go on, etc. I think I will not worry any longer. I want to thank you for all the dropping testimonials -- made me feel much better!</p>

<p>OK guys, we all have to remember to wear our neck straps and change lenses over soft stuff...</p>

<p>Bruce did good in changing his 75mm <strong>at the least</strong> over a table.</p>

<p>Now, Joseph Wisniewski's concern for "centration" on a Leica lens is a bit over the top. The internal elements and groups in a Leica made lens are housed in robust brass tubes, with <strong>super tight tolerances’. </strong>De-centering would have to be felt in the action of the mounting, focusing, or aperture ring movement. If they all feel normal, no such flaw exists. There's simply <strong>no play</strong> for the glass to make <strong>any</strong> movement.</p>

<blockquote>

<p>"decenter an element. (it's harder to delaminate or break the adhesive bonds that hold elements together)"</p>

</blockquote>

<p>This statement is ONLY true with Zoom lenses, especially the ones that have plastic/polycarbonate construction.<br />Shock or impact <strong>can</strong> fracture the epoxy/cement/balsam in 'solid prime lenses' like that of Zeiss or Leica brands.</p>

<p>The 75/2.0 has moving elements that help with close focusing. As Richard suggests I'd check your results especially at the nearer distances just to make sure.</p>

<p>True Peter, but "floating element" CRC designs are <strong>directly connected</strong> to the focus mechanism. Bruce would still <strong>feel</strong> something...</p>

<p>I recently had an Olympus 24mm f/2 in for service, where the lens focus was fully seized. No signs of impact whatsoever. It ended up being that the floating element chamber had experienced grease failure. No play and bad grease resulted in a jammed lens.</p>

<p>Slightly <strong>displaced</strong> elements have even obstructed nearby aperture blades. A rare example where you <strong>couldn't feel</strong> the effects of a shock or impact, but still had internal damage. </p>

<p>But, this has only occurred on those previously mentioned"plastic" made Zooms... (Especially Canon)</p>

<p>Do not worry damage is visible when it happens ! Ex: I dropped an M6 + summicron 35 at an airport safety check, not more than 30cm on the metal slide of the x ray machine: Result the lens thread was destroyed. I could not focus until replaced 300 euros later. However the lens block looks and was solid enough no damage. How do you expect "de centering" lenses that are held so tight, either they break or they stay in place ! Do NOT bother, wood is not so hard and if I'm right 6 inches is only 15cm! not so high !</p>

<p>Just returning with a photo of the damage sustained to my 35 'cron after I dropped it atleast one meter (from where the camera was hanging around my neck) onto the concrete flooring of the Stockholm subway. I haven't noticed any imperfections in my images that might be related to this, after about a year or so of use since one of the most horrific and embaressing accidents of my life.</p>

<p><a href="http://img38.imageshack.us/i/12314o.jpg/" target="_blank"><img src="http://img38.imageshack.us/img38/897/12314o.th.jpg" border="0" alt="" /></a></p>

<p>Morgan, as much as that damaged 35'cron hurts to look at or imagine, <strong>you've got a pretty good life</strong> going there, if that's;</p>

<blockquote>

<p>"one of the most horrific and embaressing accidents of my life"</p>

</blockquote>

<blockquote>

<p>If it dropped in a non vertical line, a part of the impact would have been transfered into some rotation and that would lessen the effect.</p>

</blockquote>

<p>How do you drop something non-vertically? Anomalous gravitational field? You could impart a horizontal component of motion, but the free-fall vertical component would still be determined by gravitational accelleration, no? Unless you throw it down. Otherwise, I think the impact will be the same. Agree- or disagree?</p>

<blockquote>

 

</blockquote>