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LEE209 spectral response — original published curveOpen full-size image ↗
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Neutral Density Filters

LEE209Neutral Density Filters

LEE209 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.

  • Product family: Neutral Density Filters
  • Measured wavelength range: 380–780 nm
  • Published response: Transmittance

Measured interval is not the passband. Values shown are sample measurements. Final specifications are agreed for your order.

MEASURED OPTICAL RESPONSE

Read the light.

Original published sample data.

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Nearest measured point shown; no interpolation or extrapolation. Original sample values are preserved, including values outside 0–100%. Samples are selection references, not production acceptance limits.

OPTICAL PERFORMANCE · LEE209

Read the numbers.
Understand the response.

Measured wavelength range

380-780 nm. Performance outside this measured interval is not established by this curve.

Measured optical density

Approximately 0.39-0.44 over 400-700 nm.

Exposure reduction

Approximately 1.28-1.45 stops across the same interval. Actual exposure change depends on the source and detector response.

These 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.

OPERATING CONDITIONS

Match the complete optical system.

Match the full source band.

Compare the source emission spectrum with the filter curve. Include the source bandwidth, rather than relying on the nominal wavelength alone.

Check unwanted response.

Compare the complete measured response with your detector sensitivity. Confirm any additional blocking needed for your system.

Define the incidence conditions.

Specify the working angle and whether the beam is collimated or converging. Confirm the required response under those conditions.

Confirm the physical fit.

Provide the available mounting space, required shape, dimensions and thickness. Physical specifications will be confirmed for your assembly.

APPLICATIONS

Where this profile can help.

Imaging & Photography

Manage exposure, unwanted wavelengths and reflection.

Industrial & Machine Vision

Inspection, detection, sorting and image contrast.

Research & Instrumentation

Spectral selection, beam paths and measurement systems.

Solar Simulation

Source shaping for solar-cell testing and laboratory simulators.

Application examples are starting points for evaluation; suitability depends on the complete optical system.

CUSTOM & ENQUIRY

Tell us what
your design needs.

Start with LEE209 and discuss the spectral response, physical format and operating conditions.

Include in your enquiry

  • Target wavelengths and required transmission or blocking
  • Light source and detector model, or their spectra
  • Working angle, beam geometry and operating environment
  • Required shape, dimensions, thickness and mounting constraints
  • Sample quantity, expected order quantity and project timing

TECHNICAL RESOURCES

Take the data
into your design.

LEE209 spectrum data CSV ↓KUPO Optics catalog Download ↗Explore Neutral Density Filters →