----- Original Message ----- From: "michael Sta. Maria" <littlwing5@xxxxxxxxx> To: <rollei_list@xxxxxxxxxxxxx> Sent: Wednesday, April 27, 2005 9:54 AM Subject: [rollei_list] Bubbles in Schneider Lens!!! > Hello all, > This is probably a stupid question, but I > just won a bid on *bay for a 210mm symmar-s lens and > now I am questioning whether I really want it. In the > description there are bubbles barely visible between > the lens elements if seen at an angle. Does this > affect image quality? Where do these bubbles come > from? > > Please have a look: Item number: 7508963819 on *bay > Its very difficult to see anything in the photo. However, I think what the guy means is what appear to be bubbles around the edge of the lens. This is the anti-reflection paint on the edges of the elements flaking off. This seems to be common on Schneider lenses for some reason. The seller states this is the cement holding the element to the lens mount but there is no such cement, its the paint. If this is so its not serious and probably has no effect on the lens performance. Bubbles in the cement for the elements would be a problem because it indicates the synthetic cement has not been cured correctly and is beginning to separate. Small bubbles do appear in some type of optical glass but are very rare in modern glass. They were fairly common in some types of dense Barium glass in the very distant past because the melting point of these glasses was so high and because the technology to remove entrapped gasses had not been developed. Glass making techniques changed during and after WW-2 so such bubbles have become very rare. The Symmar-S is an excellent lens. If this one is in otherwise good condition, and if the "bubbles" are simply places where the edge paint has separated, its a safe buy. I have no idea what these are worth on the used market so I can't comment on value. Get a right of return on the thing so you can really inspect it. Look it over for any sign of mechanical damage; indications of being dropped or banged hard, etc. Look through it with a strong light and at the surfaces with both transmitted light and grazing reflected light using a magnifer. Scratches do matter and lenses with many scratches should be rejected. "Cleaning marks" are scratches and, if there are many, will diffuse the image just like ground glass. They also show carelessness in handling. Good luck. --- Richard Knoppow Los Angeles, CA, USA dickburk@xxxxxxxxxxxxx