used lens problem

[jonathan_paul_davies]

<p>Hello</p>

<p>I've just purchased a used large format lens (Schneider 150mm apo symmar) over the internet. On the whole the lens looks in good shape but there is one thing I am concerned about and this being my first large format lens I have no experience or means of comparison to tell if my concerns are warranted.</p>

<p>At the very edge of the front lens there are some rather large marks inside the lens. I don't know if it is some kind of separation either between the body and the lens or the coatings of the lens, or alternatively if it could be some kind of growth? This being my first large format lens I was wondering if these marks are normal or I should consider returning the lens?</p>

<p>Kind regards</p>

<p>Jon</p>

[leighb]

<p>Are you talking about small white marks around the edge of the lens elements?</p>

<p>That's called "Schneideritis", unique to Schneider lenses. It's such a common problem that it has a name.</p>

<p>In most cases it will not affect picture quality. If it's really severe it could cause a bit of flare.</p>

<p>- Leigh</p>

[jonathan_paul_davies]

<p>Thanks Leigh</p>

<p>yes, there are about 6 or so on one side of the lens, roughly 1mm diameter. They don't extend past the small lip on which the lens seems to sit.</p>

<p>Is it something that happens at the manufacturing stage or does it develop over time, I'm wondering if it will get worse?</p>

<p>Jon</p>

[leighb]

<p>It develops over time.</p>

<p>I think it's a problem with the black anodizing on the aluminum, but I can't swear to it.</p>

<p>I've seen examples far worse than you described, more like a teenager with a bad case of acne.</p>

<p>- Leigh</p>

 

[jonathan_paul_davies]

<p>Thanks Leigh</p>

<p>I appreciate being able to pick your brain.</p>

<p>Jon</p>

[leighb]

<blockquote>

<p>I appreciate being able to pick your brain.</p>

</blockquote>

<p>I was wondering what happened to it. At least now I have an excuse. :D</p>

<p>Yeah, Schneideritis is nothing to worry about. Enjoy the lens.</p>

<p>You might want to join the Large Format Photography Forum at http://www.largeformatphotography.info/forum/<br /> They talk about LF all the time.</p>

<p>- Leigh</p>

[michael_briggs2]

<p>Are the marks on the edge of the lens element? Do they look white / reflective? If so, then the marks are probably "Schneideritis", as already mentioned. Schneideritis is separation of the black anti-reflection paint used on the edge of the lens from the glass. I'm surprised for it to occurr on a lens as recent as an Apo-Symmar. </p>

[tom_cheshire]

<p>Usually the fix for that is to remove the glass and repaint the edges with a flat black paint like Floquil (model railroad paint).</p>

[brit]

<p>Funny this is a photograph forum but lots of posts go along the lines of people trying to describe something or second guess what the something might be ;p Take a photo as best you can and show it here.</p>