From: pcdhSpamMeSenseless@electrooptical.net   
      
   On 11/06/2013 08:18 AM, Helpful person wrote:   
   > On Tuesday, November 5, 2013 11:30:56 PM UTC-5, gr wrote:   
   >> On 11/5/2013 1:23 PM, Helmut Wabnig wrote:   
   >>   
   >>> Any ideas how to mitigate a severe scratch in   
   >>> the front lens of a fotoobjective?   
   >>> Can only take shots in nebula   
   >>> or have to correct fotos with software effects.   
   >>   
   >>> Polishing?   
   >>> Filling the crack with something and polish?   
   >>> Oil on the front lens?   
   >>   
   >>> w.   
   >>   
   >> Black grease pencil is somewhat effective- I have seen special ones for   
   >> sale for use with eyeglass scratches.   
   >>   
   >> Windshield repair places have some UV cure filler they use for big   
   >>   
   >> dings- maybe.   
   >   
   > Don't forget you need to maintain the surface figure.  Anything   
   > that changes the surface profile will result in image   
   > artifacts.   
   >   
   > http://www.richardfisher.com   
   >   
      
   Yup.  That's why just using black paint to effectively delete that area   
   of the surface is a win.  Of course, the edges of the paint will cause a   
   certain amount of scatter.   
      
   Cheers   
      
   Phil Hobbs   
      
   --   
   Dr Philip C D Hobbs   
   Principal Consultant   
   ElectroOptical Innovations LLC   
   Optics, Electro-optics, Photonics, Analog Electronics   
      
   160 North State Road #203   
   Briarcliff Manor NY 10510   
      
   hobbs at electrooptical dot net   
   http://electrooptical.net   
      
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