Bandpass Lens Filter 500 nm, Select your size, 500 nm peak wavelength, useful range between 450-550 nm, useful range FWHM: 100 (±5 nm)

The BP500 narrow bandpass filter is an optical lens filter engineered to pass light with a peak wavelength of 500 nm and a useful range between 450–550 nm, while efficiently blocking all other wavelengths.

It easily mounts on a machine vision lens using the standard filter thread.

A variety of available thread sizes ensures compatibility with different lens types, providing a secure fit and maintaining consistent optical performance across a wide range of machine vision and imaging applications.

How the BP500 Narrow Bandpass Filter Works

Narrow bandpass filters work by allowing only a specific portion of the light spectrum to pass while effectively blocking all other wavelengths.

For the BP500 filter, light at a central wavelength of 500 nm achieves peak transmission above 90%, and within the effective range of 470–530 nm, transmission remains above 80%.

Specification
Filter type	Narrow Bandpass
Peak wavelength	500 nm
Peak wavelength color	Green
Useful wavelength range	450-550 nm

BP500 Lens Filter Size Options

Because lenses come in different sizes, the BP500 filter is offered in multiple standard thread sizes suitable for both small and large lenses.

• C-mount filter

• 0.5 thread (pitch): M22.5×0.5, M25.5×0.5, M27×0.5, M30.5×0.5, M34×0.5, M35.5×0.5, M37×0.5, M37.5×0.5, M40.5×0.5

• 0.75 thread (pitch): M37×0.75, M43×0.75, M46×0.75, M49×0.75, M52×0.75, M55×0.75, M58×0.75, M60×0.75, M62×0.75, M67×0.75, M72×0.75

Need help with C-mount (CMT) filter thread installation?

Submit the form below to get instant access to the manual on how to mount it and see which lenses it’s compatible with!

BP500 Narrow Bandpass Filter: Technical Overview and Practical Applications

The BP500 bandpass filter is designed to transmit light centered around 500 nm while blocking unwanted wavelengths outside its passband. This precise wavelength control enhances image contrast, color accuracy, and measurement reliability for a wide variety of optical systems.

By selecting a specific wavelength (for example 500 nm), the BP500 filter effectively becomes a ‘color’ filter for the monochrome imaging: it allows only the target color (green) to pass and suppresses its complementary and nearby wavelengths. Adding a color lens filter “works on a subtraction idea” — for instance, a green filter makes green shades stay bright while rendering complementary colors dark.

In practical use, combining a white-light or broad-spectrum illumination source with the BP500 filter isolates a narrow spectral band centered at 500 nm. This results in higher contrast, sharper object differentiation, fewer unwanted reflections, and greater image stability. Such performance is especially valuable in machine vision and inspection applications, where subtle differences in material, color, or surface features must be reliably detected under variable lighting conditions.

BP500 Bandpass Filter Typical Applications:

• Green LED or laser lighting systems

• Machine vision and automated inspection

• Color sorting and material differentiation 

• Optical contrast enhancement and fluorescence imaging

BP500 Filter Compatibility with Lenses and Cameras

The BP500 filter provides versatile mounting options and can be seamlessly integrated into existing imaging systems without the need to modify your current camera or lens.

In most machine vision setups, it can be directly mounted to the front of the lens, as standard lenses typically include a filter thread for attaching optical filters.

When you're using a C-mount lens on a GigE camera or USB3 camera, the BP500 filter can also be positioned inside the C-mount interface rather than mounted on the lens front. This method is particularly useful when the lens does not feature a front filter thread.

In this configuration, the filter sits securely between the camera and the lens, remaining fixed in the optical path. This stable placement helps maintain optical alignment and delivers consistent image quality.

Key Benefits for BP500 Narrow Bandpass Filter:

• High transmission efficiency at the 500 nm center wavelength
• Strong blocking of unwanted out-of-band light
• Enhanced image contrast and overall signal clarity
• Consistent optical performance under changing environmental or lighting conditions
• Reliable and repeatable results in precision imaging and measurement applications

Select Your BP500 Narrow Bandpass Filter

Choose the BP500 narrow bandpass filter with the thread size that matches your lens. For help selecting the correct size or wavelength, contact our technical team.