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What's this on my sensor ??

km6xz

St Petersburg, RU
3572 posts

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"RE: What's this on my sensor ??"

km6xz Moderator Awarded for his in-depth knowledge in various areas, including Portraits and Urban Photography Nikonian since 22nd Jan 2009
Sat 16-Feb-13 11:35 PM | edited Sat 16-Feb-13 11:36 PM by km6xz

Hello JohnE
The AA filters used in are made of Lithium Niobate (LiNbO3) which was rated at 5.0Mohs hardness which corresponds to around Vickers microhardness value of 400kg/mm^2 in older materials handbooks but later studies place the microhardness up around 650 kg/mm^2 with the property of increased hardness with increased load. By doping with Fe, which is done to alter the diffraction index (needed in AA filters), increases Vickers microhardness up to around 750kg/mm^2
Here is a study by K G SUBHADRA, K KISHAN RAO and D B SIRDESHMUKH published by Indian Academy of Sciences in 2000
http://www.ias.ac.in/matersci/bmsapr2000/147.pdf that describes the newer findings.

The material is rather inert so is unaffected by any common solvents or water making cleaning safe with just about any solvent you can get without a license.
For surface hardness, the newer figures place it close to Quartz crystal, above fused Quartz, above window glass(Moh 5.5), steel and tooth enamel.
Stan
St Petersburg Russia

Visit my Nikonians gallery.

This is a hot, active topic! What's this on my sensor ?? [View all] , Ray B , Tue 05-Feb-13 11:41 AM
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