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2PCS Diameter 20mm Optical Glass Focal Length 13mm Height 8.1mm LED Optics Plano convex condenser Lens for LED - - Amazon.com
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Focal length, explained by RP Photonics Encyclopedia; focal distance, dioptric power, curved mirror, lens equation, microscope, photographic objective, focus, beam radius
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Focal length, explained by RP Photonics Encyclopedia; focal distance, dioptric power, curved mirror, lens equation, microscope, photographic objective, focus, beam radius
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