{"title":"Neutral Density Filters","description":"\u003cp\u003eReduce light intensity across a useful wavelength region. Compare the transmission profile of each design to select attenuation that suits the source and detector.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow to choose:\u003c\/strong\u003e Check spectral neutrality over your operating range. Confirm the required optical density and tolerance; reference measurements are not a calibration certificate.\u003c\/p\u003e","products":[{"product_id":"lee299","title":"LEE299 Neutral-density filter","description":"\u003cnav aria-label=\"Product family\"\u003e\u003cp\u003e\u003ca href=\"\/collections\/all-products\"\u003eAll optics\u003c\/a\u003e \/ \u003ca href=\"\/collections\/neutral-density-nd-filter\"\u003eNeutral Density Filters\u003c\/a\u003e\u003c\/p\u003e\u003c\/nav\u003e\u003cstyle\u003e\n.ko-reviewed{color:#222;font-family:inherit;line-height:1.65;overflow-wrap:anywhere}\n.ko-reviewed *{box-sizing:border-box}.ko-reviewed h2,.ko-reviewed h3{color:#005F96;line-height:1.3}\n.ko-reviewed h2{font-size:24px;margin:0 0 1rem}.ko-reviewed h3{font-size:19px;margin:1.7rem 0 .65rem}\n.ko-reviewed p{margin:.6rem 0 1rem}.ko-reviewed ul{padding-left:1.25rem;margin:.6rem 0 1rem}\n.ko-reviewed li{padding-left:.15rem;margin:.55rem 0}.ko-reviewed .ko-note{border-left:3px solid #c9dae4;padding:.65rem 1rem;background:#f7fafc;font-size:.95em}\n.ko-reviewed a{color:#005F96;text-decoration:underline}\n\n@media(max-width:480px){.ko-reviewed h2{font-size:22px}.ko-reviewed h3{font-size:18px}.ko-reviewed .ko-note{padding:.65rem .8rem}}\n\u003c\/style\u003e\u003csection class=\"ko-reviewed\"\u003e\u003ch2 class=\"ko-catalog-description-title\"\u003eNeutral-density filter (LEE299)\u003c\/h2\u003e\n\u003cp\u003eLEE299 is a neutral-density filter. The measured curve transmits approximately 1.5-3% over 400-700 nm. It provides attenuation for exposure and detector-level adjustment; the variation across wavelength should be considered when color balance matters.\u003c\/p\u003e\n\u003ch3\u003eOptical performance\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMeasured wavelength range:\u003c\/strong\u003e 380-780 nm. Performance outside this measured interval is not established by this curve.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMeasured optical density:\u003c\/strong\u003e Approximately 1.52-1.81 over 400-700 nm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExposure reduction:\u003c\/strong\u003e Approximately 5.06-6.02 stops across the same interval. Actual exposure change depends on the source and detector response.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCustomization:\u003c\/strong\u003e We can customize stock and sample-book designs. Tell us the wavelength response, size and operating conditions you need.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"ko-note\"\u003eThese values come from the measured samples and help you choose a starting design. We will agree the final specification for your order. Custom versions have their own specifications and measured curves.\u003c\/p\u003e\n\u003ch3\u003eApplications to consider\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eImaging exposure control:\u003c\/strong\u003e Evaluate attenuation when the required shutter speed, aperture or illumination level leaves the detector close to saturation. Check color balance across the camera response.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLighting-level adjustment:\u003c\/strong\u003e Consider reducing output without changing the source drive setting. Choose attenuation and thermal conditions for your fixture.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptical test benches:\u003c\/strong\u003e Consider a transmission attenuator for detector-range adjustment. Confirm wavelength-dependent attenuation and power handling against the test setup.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eChoosing this filter\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eMatch attenuation to the wavelength range of the source and detector. Optical density and exposure reduction vary with wavelength.\u003c\/li\u003e\n\u003cli\u003eFor high-power light sources, tell us the power density at the filter, beam size and operating conditions so we can assess a suitable optic.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eCustom options\u003c\/h3\u003e\n\u003cp\u003eStart with this stock or sample-book design, then tell us what you need to change. We can discuss the wavelength bands, transmission, blocking, angle, glass material, size and operating conditions with you, and agree a specification for your custom filter.\u003c\/p\u003e\u003c\/section\u003e\u003ch3\u003eTransmission spectrum\u003c\/h3\u003e\u003ciframe src=\"https:\/\/charts.kupooptics.com\/LEE299.html\" title=\"LEE299 transmission spectrum with wavelength readout\" loading=\"lazy\" width=\"100%\" height=\"880\" style=\"border:0;width:100%;height:clamp(640px,calc(43vw + 320px),880px);\" referrerpolicy=\"no-referrer-when-downgrade\"\u003e\u003c\/iframe\u003e\u003csection class=\"ko-reviewed ko-product-faq\" aria-label=\"Product questions\"\u003e\u003ch2\u003eQuestions about LEE299\u003c\/h2\u003e\n\u003ch3\u003eHow much exposure reduction should I expect from LEE299?\u003c\/h3\u003e\n\u003cp\u003eThe sample calculation gives approximately 5.06-6.02 stops over 400-700 nm. Its optical density is approximately 1.52-1.81 over 400-700 nm. These estimates help you choose attenuation; check the result with your actual source and detector.\u003c\/p\u003e\n\u003ch3\u003eIs LEE299 equally neutral across blue, green and red?\u003c\/h3\u003e\n\u003cp\u003eThe measured transmission varies from 1.5-3% over 400-700 nm. That is the variation to assess when color balance matters. Compare the full visible curve with the wavelengths used by your source rather than treating the attenuation as perfectly flat.\u003c\/p\u003e\u003c\/section\u003e\u003cp\u003e\u003ca href=\"\/pages\/contact\"\u003e\u003cstrong\u003eDiscuss this filter with KUPO\u003c\/strong\u003e\u003c\/a\u003e - include the product reference, source wavelength, working angle and required dimensions.\u003c\/p\u003e\u003cstyle\u003e#MainContent .ko-reviewed\u003eh2.ko-catalog-description-title{font-size:27px;font-weight:500;line-height:1.4;letter-spacing:-.01em;color:#0c324b;background:#f0f6f9;padding:20px 24px;}#MainContent .ko-reviewed\u003eh2.ko-catalog-description-title+p{border-bottom:0;}@media(max-width:650px){#MainContent .ko-reviewed\u003eh2.ko-catalog-description-title{font-size:24px;}}\u003c\/style\u003e","brand":"KUPO Optics","offers":[{"title":"Neutral Density (ND) Filter","offer_id":48516671209727,"sku":"LEE299","price":0.0,"currency_code":"TWD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0818\/8651\/1359\/files\/lee299-spectrum.jpg?v=1778712948"},{"product_id":"lee211","title":"LEE211 Neutral-density filter","description":"\u003cnav aria-label=\"Product family\"\u003e\u003cp\u003e\u003ca href=\"\/collections\/all-products\"\u003eAll optics\u003c\/a\u003e \/ \u003ca href=\"\/collections\/neutral-density-nd-filter\"\u003eNeutral Density Filters\u003c\/a\u003e\u003c\/p\u003e\u003c\/nav\u003e\u003cstyle\u003e\n.ko-reviewed{color:#222;font-family:inherit;line-height:1.65;overflow-wrap:anywhere}\n.ko-reviewed *{box-sizing:border-box}.ko-reviewed h2,.ko-reviewed h3{color:#005F96;line-height:1.3}\n.ko-reviewed h2{font-size:24px;margin:0 0 1rem}.ko-reviewed h3{font-size:19px;margin:1.7rem 0 .65rem}\n.ko-reviewed p{margin:.6rem 0 1rem}.ko-reviewed ul{padding-left:1.25rem;margin:.6rem 0 1rem}\n.ko-reviewed li{padding-left:.15rem;margin:.55rem 0}.ko-reviewed .ko-note{border-left:3px solid #c9dae4;padding:.65rem 1rem;background:#f7fafc;font-size:.95em}\n.ko-reviewed a{color:#005F96;text-decoration:underline}\n\n@media(max-width:480px){.ko-reviewed h2{font-size:22px}.ko-reviewed h3{font-size:18px}.ko-reviewed .ko-note{padding:.65rem .8rem}}\n\u003c\/style\u003e\u003csection class=\"ko-reviewed\"\u003e\u003ch2 class=\"ko-catalog-description-title\"\u003eNeutral-density filter (LEE211)\u003c\/h2\u003e\n\u003cp\u003eLEE211 is a neutral-density filter. The measured curve transmits approximately 6-7.3% over 400-700 nm. It provides attenuation for exposure and detector-level adjustment; the variation across wavelength should be considered when color balance matters.\u003c\/p\u003e\n\u003ch3\u003eOptical performance\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMeasured wavelength range:\u003c\/strong\u003e 380-780 nm. Performance outside this measured interval is not established by this curve.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMeasured optical density:\u003c\/strong\u003e Approximately 1.14-1.22 over 400-700 nm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExposure reduction:\u003c\/strong\u003e Approximately 3.77-4.06 stops across the same interval. Actual exposure change depends on the source and detector response.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCustomization:\u003c\/strong\u003e We can customize stock and sample-book designs. Tell us the wavelength response, size and operating conditions you need.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"ko-note\"\u003eThese values come from the measured samples and help you choose a starting design. We will agree the final specification for your order. Custom versions have their own specifications and measured curves.\u003c\/p\u003e\n\u003ch3\u003eApplications to consider\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eImaging exposure control:\u003c\/strong\u003e Evaluate attenuation when the required shutter speed, aperture or illumination level leaves the detector close to saturation. Check color balance across the camera response.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLighting-level adjustment:\u003c\/strong\u003e Consider reducing output without changing the source drive setting. Choose attenuation and thermal conditions for your fixture.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptical test benches:\u003c\/strong\u003e Consider a transmission attenuator for detector-range adjustment. Confirm wavelength-dependent attenuation and power handling against the test setup.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eChoosing this filter\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eMatch attenuation to the wavelength range of the source and detector. Optical density and exposure reduction vary with wavelength.\u003c\/li\u003e\n\u003cli\u003eFor high-power light sources, tell us the power density at the filter, beam size and operating conditions so we can assess a suitable optic.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eCustom options\u003c\/h3\u003e\n\u003cp\u003eStart with this stock or sample-book design, then tell us what you need to change. We can discuss the wavelength bands, transmission, blocking, angle, glass material, size and operating conditions with you, and agree a specification for your custom filter.\u003c\/p\u003e\u003c\/section\u003e\u003ch3\u003eTransmission spectrum\u003c\/h3\u003e\u003ciframe src=\"https:\/\/charts.kupooptics.com\/LEE211.html\" title=\"LEE211 transmission spectrum with wavelength readout\" loading=\"lazy\" width=\"100%\" height=\"880\" style=\"border:0;width:100%;height:clamp(640px,calc(43vw + 320px),880px);\" referrerpolicy=\"no-referrer-when-downgrade\"\u003e\u003c\/iframe\u003e\u003csection class=\"ko-reviewed ko-product-faq\" aria-label=\"Product questions\"\u003e\u003ch2\u003eQuestions about LEE211\u003c\/h2\u003e\n\u003ch3\u003eHow much exposure reduction should I expect from LEE211?\u003c\/h3\u003e\n\u003cp\u003eThe sample calculation gives approximately 3.77-4.06 stops over 400-700 nm. Its optical density is approximately 1.14-1.22 over 400-700 nm. These estimates help you choose attenuation; check the result with your actual source and detector.\u003c\/p\u003e\n\u003ch3\u003eIs LEE211 equally neutral across blue, green and red?\u003c\/h3\u003e\n\u003cp\u003eThe measured transmission varies from 6-7.3% over 400-700 nm. That is the variation to assess when color balance matters. Compare the full visible curve with the wavelengths used by your source rather than treating the attenuation as perfectly flat.\u003c\/p\u003e\u003c\/section\u003e\u003cp\u003e\u003ca href=\"\/pages\/contact\"\u003e\u003cstrong\u003eDiscuss this filter with KUPO\u003c\/strong\u003e\u003c\/a\u003e - include the product reference, source wavelength, working angle and required dimensions.\u003c\/p\u003e\u003cstyle\u003e#MainContent .ko-reviewed\u003eh2.ko-catalog-description-title{font-size:27px;font-weight:500;line-height:1.4;letter-spacing:-.01em;color:#0c324b;background:#f0f6f9;padding:20px 24px;}#MainContent .ko-reviewed\u003eh2.ko-catalog-description-title+p{border-bottom:0;}@media(max-width:650px){#MainContent .ko-reviewed\u003eh2.ko-catalog-description-title{font-size:24px;}}\u003c\/style\u003e","brand":"KUPO Optics","offers":[{"title":"Neutral Density (ND) Filter","offer_id":48516671242495,"sku":"LEE211","price":0.0,"currency_code":"TWD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0818\/8651\/1359\/files\/lee211-spectrum.jpg?v=1778712948"},{"product_id":"lee210","title":"LEE210 Neutral-density filter","description":"\u003cnav aria-label=\"Product family\"\u003e\u003cp\u003e\u003ca href=\"\/collections\/all-products\"\u003eAll optics\u003c\/a\u003e \/ \u003ca href=\"\/collections\/neutral-density-nd-filter\"\u003eNeutral Density Filters\u003c\/a\u003e\u003c\/p\u003e\u003c\/nav\u003e\u003cstyle\u003e\n.ko-reviewed{color:#222;font-family:inherit;line-height:1.65;overflow-wrap:anywhere}\n.ko-reviewed *{box-sizing:border-box}.ko-reviewed h2,.ko-reviewed h3{color:#005F96;line-height:1.3}\n.ko-reviewed h2{font-size:24px;margin:0 0 1rem}.ko-reviewed h3{font-size:19px;margin:1.7rem 0 .65rem}\n.ko-reviewed p{margin:.6rem 0 1rem}.ko-reviewed ul{padding-left:1.25rem;margin:.6rem 0 1rem}\n.ko-reviewed li{padding-left:.15rem;margin:.55rem 0}.ko-reviewed .ko-note{border-left:3px solid #c9dae4;padding:.65rem 1rem;background:#f7fafc;font-size:.95em}\n.ko-reviewed a{color:#005F96;text-decoration:underline}\n\n@media(max-width:480px){.ko-reviewed h2{font-size:22px}.ko-reviewed h3{font-size:18px}.ko-reviewed .ko-note{padding:.65rem .8rem}}\n\u003c\/style\u003e\u003csection class=\"ko-reviewed\"\u003e\u003ch2 class=\"ko-catalog-description-title\"\u003eNeutral-density filter (LEE210)\u003c\/h2\u003e\n\u003cp\u003eLEE210 is a neutral-density filter. The measured curve transmits approximately 20.6-21.8% over 400-700 nm. It provides attenuation for exposure and detector-level adjustment; the variation across wavelength should be considered when color balance matters.\u003c\/p\u003e\n\u003ch3\u003eOptical performance\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMeasured wavelength range:\u003c\/strong\u003e 380-780 nm. Performance outside this measured interval is not established by this curve.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMeasured optical density:\u003c\/strong\u003e Approximately 0.66-0.69 over 400-700 nm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExposure reduction:\u003c\/strong\u003e Approximately 2.2-2.28 stops across the same interval. Actual exposure change depends on the source and detector response.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCustomization:\u003c\/strong\u003e We can customize stock and sample-book designs. Tell us the wavelength response, size and operating conditions you need.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"ko-note\"\u003eThese values come from the measured samples and help you choose a starting design. We will agree the final specification for your order. Custom versions have their own specifications and measured curves.\u003c\/p\u003e\n\u003ch3\u003eApplications to consider\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eImaging exposure control:\u003c\/strong\u003e Evaluate attenuation when the required shutter speed, aperture or illumination level leaves the detector close to saturation. Check color balance across the camera response.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLighting-level adjustment:\u003c\/strong\u003e Consider reducing output without changing the source drive setting. Choose attenuation and thermal conditions for your fixture.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptical test benches:\u003c\/strong\u003e Consider a transmission attenuator for detector-range adjustment. Confirm wavelength-dependent attenuation and power handling against the test setup.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eChoosing this filter\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eMatch attenuation to the wavelength range of the source and detector. Optical density and exposure reduction vary with wavelength.\u003c\/li\u003e\n\u003cli\u003eFor high-power light sources, tell us the power density at the filter, beam size and operating conditions so we can assess a suitable optic.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eCustom options\u003c\/h3\u003e\n\u003cp\u003eStart with this stock or sample-book design, then tell us what you need to change. We can discuss the wavelength bands, transmission, blocking, angle, glass material, size and operating conditions with you, and agree a specification for your custom filter.\u003c\/p\u003e\u003c\/section\u003e\u003ch3\u003eTransmission spectrum\u003c\/h3\u003e\u003ciframe src=\"https:\/\/charts.kupooptics.com\/LEE210.html\" title=\"LEE210 transmission spectrum with wavelength readout\" loading=\"lazy\" width=\"100%\" height=\"880\" style=\"border:0;width:100%;height:clamp(640px,calc(43vw + 320px),880px);\" referrerpolicy=\"no-referrer-when-downgrade\"\u003e\u003c\/iframe\u003e\u003csection class=\"ko-reviewed ko-product-faq\" aria-label=\"Product questions\"\u003e\u003ch2\u003eQuestions about LEE210\u003c\/h2\u003e\n\u003ch3\u003eHow much exposure reduction should I expect from LEE210?\u003c\/h3\u003e\n\u003cp\u003eThe sample calculation gives approximately 2.2-2.28 stops over 400-700 nm. Its optical density is approximately 0.66-0.69 over 400-700 nm. These estimates help you choose attenuation; check the result with your actual source and detector.\u003c\/p\u003e\n\u003ch3\u003eIs LEE210 equally neutral across blue, green and red?\u003c\/h3\u003e\n\u003cp\u003eThe measured transmission varies from 20.6-21.8% over 400-700 nm. That is the variation to assess when color balance matters. Compare the full visible curve with the wavelengths used by your source rather than treating the attenuation as perfectly flat.\u003c\/p\u003e\u003c\/section\u003e\u003cp\u003e\u003ca href=\"\/pages\/contact\"\u003e\u003cstrong\u003eDiscuss this filter with KUPO\u003c\/strong\u003e\u003c\/a\u003e - include the product reference, source wavelength, working angle and required dimensions.\u003c\/p\u003e\u003cstyle\u003e#MainContent .ko-reviewed\u003eh2.ko-catalog-description-title{font-size:27px;font-weight:500;line-height:1.4;letter-spacing:-.01em;color:#0c324b;background:#f0f6f9;padding:20px 24px;}#MainContent .ko-reviewed\u003eh2.ko-catalog-description-title+p{border-bottom:0;}@media(max-width:650px){#MainContent .ko-reviewed\u003eh2.ko-catalog-description-title{font-size:24px;}}\u003c\/style\u003e","brand":"KUPO Optics","offers":[{"title":"Neutral Density (ND) Filter","offer_id":48516671275263,"sku":"LEE210","price":0.0,"currency_code":"TWD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0818\/8651\/1359\/files\/lee210-spectrum.jpg?v=1778712949"},{"product_id":"lee209","title":"LEE209 Neutral-density filter","description":"\u003cnav aria-label=\"Product family\"\u003e\u003cp\u003e\u003ca href=\"\/collections\/all-products\"\u003eAll optics\u003c\/a\u003e \/ \u003ca href=\"\/collections\/neutral-density-nd-filter\"\u003eNeutral Density Filters\u003c\/a\u003e\u003c\/p\u003e\u003c\/nav\u003e\u003cstyle\u003e\n.ko-reviewed{color:#222;font-family:inherit;line-height:1.65;overflow-wrap:anywhere}\n.ko-reviewed *{box-sizing:border-box}.ko-reviewed h2,.ko-reviewed h3{color:#005F96;line-height:1.3}\n.ko-reviewed h2{font-size:24px;margin:0 0 1rem}.ko-reviewed h3{font-size:19px;margin:1.7rem 0 .65rem}\n.ko-reviewed p{margin:.6rem 0 1rem}.ko-reviewed ul{padding-left:1.25rem;margin:.6rem 0 1rem}\n.ko-reviewed li{padding-left:.15rem;margin:.55rem 0}.ko-reviewed .ko-note{border-left:3px solid #c9dae4;padding:.65rem 1rem;background:#f7fafc;font-size:.95em}\n.ko-reviewed a{color:#005F96;text-decoration:underline}\n\n@media(max-width:480px){.ko-reviewed h2{font-size:22px}.ko-reviewed h3{font-size:18px}.ko-reviewed .ko-note{padding:.65rem .8rem}}\n\u003c\/style\u003e\u003csection class=\"ko-reviewed\"\u003e\u003ch2 class=\"ko-catalog-description-title\"\u003eNeutral-density filter (LEE209)\u003c\/h2\u003e\n\u003cp\u003eLEE209 is a neutral-density filter. The measured curve transmits approximately 36.5-41.1% over 400-700 nm. It provides attenuation for exposure and detector-level adjustment; the variation across wavelength should be considered when color balance matters.\u003c\/p\u003e\n\u003ch3\u003eOptical performance\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMeasured wavelength range:\u003c\/strong\u003e 380-780 nm. Performance outside this measured interval is not established by this curve.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMeasured optical density:\u003c\/strong\u003e Approximately 0.39-0.44 over 400-700 nm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExposure reduction:\u003c\/strong\u003e Approximately 1.28-1.45 stops across the same interval. Actual exposure change depends on the source and detector response.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCustomization:\u003c\/strong\u003e We can customize stock and sample-book designs. Tell us the wavelength response, size and operating conditions you need.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"ko-note\"\u003eThese values come from the measured samples and help you choose a starting design. We will agree the final specification for your order. Custom versions have their own specifications and measured curves.\u003c\/p\u003e\n\u003ch3\u003eApplications to consider\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eImaging exposure control:\u003c\/strong\u003e Evaluate attenuation when the required shutter speed, aperture or illumination level leaves the detector close to saturation. Check color balance across the camera response.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLighting-level adjustment:\u003c\/strong\u003e Consider reducing output without changing the source drive setting. Choose attenuation and thermal conditions for your fixture.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptical test benches:\u003c\/strong\u003e Consider a transmission attenuator for detector-range adjustment. Confirm wavelength-dependent attenuation and power handling against the test setup.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eChoosing this filter\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eMatch attenuation to the wavelength range of the source and detector. Optical density and exposure reduction vary with wavelength.\u003c\/li\u003e\n\u003cli\u003eFor high-power light sources, tell us the power density at the filter, beam size and operating conditions so we can assess a suitable optic.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eCustom options\u003c\/h3\u003e\n\u003cp\u003eStart with this stock or sample-book design, then tell us what you need to change. We can discuss the wavelength bands, transmission, blocking, angle, glass material, size and operating conditions with you, and agree a specification for your custom filter.\u003c\/p\u003e\u003c\/section\u003e\u003ch3\u003eTransmission spectrum\u003c\/h3\u003e\u003ciframe src=\"https:\/\/charts.kupooptics.com\/LEE209.html\" title=\"LEE209 transmission spectrum with wavelength readout\" loading=\"lazy\" width=\"100%\" height=\"880\" style=\"border:0;width:100%;height:clamp(640px,calc(43vw + 320px),880px);\" referrerpolicy=\"no-referrer-when-downgrade\"\u003e\u003c\/iframe\u003e\u003csection class=\"ko-reviewed ko-product-faq\" aria-label=\"Product questions\"\u003e\u003ch2\u003eQuestions about LEE209\u003c\/h2\u003e\n\u003ch3\u003eHow much exposure reduction should I expect from LEE209?\u003c\/h3\u003e\n\u003cp\u003eThe sample calculation gives approximately 1.28-1.45 stops over 400-700 nm. Its optical density is approximately 0.39-0.44 over 400-700 nm. These estimates help you choose attenuation; check the result with your actual source and detector.\u003c\/p\u003e\n\u003ch3\u003eIs LEE209 equally neutral across blue, green and red?\u003c\/h3\u003e\n\u003cp\u003eThe measured transmission varies from 36.5-41.1% over 400-700 nm. That is the variation to assess when color balance matters. Compare the full visible curve with the wavelengths used by your source rather than treating the attenuation as perfectly flat.\u003c\/p\u003e\u003c\/section\u003e\u003cp\u003e\u003ca href=\"\/pages\/contact\"\u003e\u003cstrong\u003eDiscuss this filter with KUPO\u003c\/strong\u003e\u003c\/a\u003e - include the product reference, source wavelength, working angle and required dimensions.\u003c\/p\u003e\u003cstyle\u003e#MainContent .ko-reviewed\u003eh2.ko-catalog-description-title{font-size:27px;font-weight:500;line-height:1.4;letter-spacing:-.01em;color:#0c324b;background:#f0f6f9;padding:20px 24px;}#MainContent .ko-reviewed\u003eh2.ko-catalog-description-title+p{border-bottom:0;}@media(max-width:650px){#MainContent .ko-reviewed\u003eh2.ko-catalog-description-title{font-size:24px;}}\u003c\/style\u003e","brand":"KUPO Optics","offers":[{"title":"Neutral Density (ND) Filter","offer_id":48516671308031,"sku":"LEE209","price":0.0,"currency_code":"TWD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0818\/8651\/1359\/files\/lee209-spectrum.jpg?v=1778712950"}],"url":"https:\/\/kupooptics.com\/collections\/neutral-density-nd-filter.oembed","provider":"KUPO Optics","version":"1.0","type":"link"}