In vision applications, achieving optimal image quality is crucial for accurate analysis and reliable performance. Midwest Optical filters are a trusted solution for enhancing imaging systems across a wide range of industries, from factory automation and machine vision to medical diagnostics and scientific research. These precision-engineered filters are designed to improve image contrast, reduce glare, and block unwanted wavelengths, ensuring that your vision system captures only the most relevant data. With a diverse portfolio of filters tailored to specific needs—such as polarizers, bandpass filters, and infrared cut filters—Midwest Optical delivers unmatched performance, durability, and compatibility with modern vision technologies. Whether you're aiming for higher accuracy in inspections, better control in lighting conditions, or enhanced system efficiency, Midwest Optical filters are the ideal choice for unlocking the full potential of your imaging application.
Available Products:
Bandpass Filters
MidOpt Bandpass Filters are expertly engineered for industrial imaging, offering unmatched performance across ultraviolet (UV), visible (VIS), and near-infrared (NIR) passbands. These filters deliver optimal contrast and enhance system control, repeatability, and stability. By effectively blocking interfering wavelengths, they eliminate the need for shrouds and reduce chromatic aberration, improving resolution and image quality. With anti-reflection coatings for maximum light transmission, hard-coated single-substrate fabrication, and exceptional surface quality (40/20 scratch/dig), these filters provide durability and precision for demanding applications.
MidOpt Bandpass Filters are available in a variety of mounting and size options, including threaded mounts (sizes M13.25 to M105), 25.4mm C-mounts, slip mounts, or unmounted formats. Custom shapes and sizes are also available, making them adaptable to diverse imaging needs.
These filters are used in a wide range of industries, including machine vision, factory automation, security and surveillance, license plate recognition, medical and life sciences, agricultural inspection, aerial imaging, motion analysis, photography, and cinematography.
The BP Series Broad Bandwidth Filters are designed with a broad Gaussian passband to accommodate the entire output of common LED wavelengths. These filters achieve high transmission rates (≥90%), superior out-of-band blocking, and minimize short-shifting effects with StablEDGE® design. They are ideal for machine vision, factory automation, and fluorescence imaging systems, offering sizes up to 165mm square.
The BN Series Narrow Bandwidth Filters feature a 45-55nm full width at half maximum (FWHM), with guaranteed peak transmission rates of ≥85% and superior blocking of out-of-band light. These filters are perfect for applications requiring robust performance under overwhelming ambient light, such as outdoor security surveillance, license plate recognition, and fluorescence imaging, and are available in sizes up to 165mm square.
For applications requiring even narrower bandwidths, the Bi Series Narrow Interference Filters provide 20-35nm FWHM with high transmission (≥85%) and excellent wavelength separation. Designed for use with laser diodes, these filters feature a reflective mirror-like surface to minimize thermal effects, making them ideal for life sciences and laser analysis applications. Bi Series filters are available in sizes up to 79.5mm square.
MidOpt Bandpass Filters are a critical component in imaging systems, delivering superior performance, reliability, and versatility to meet the needs of modern industrial, scientific, and creative applications.
Longpass Filter
Often referred to as “sharp-cut” filters, Longpass Filters are designed to transmit a broad spectrum of longer wavelength light while effectively blocking shorter wavelengths. They offer an economical solution for isolating specific spectral regions, achieving peak transmission rates of ≥90%. Featuring a StablEDGE® design, these filters minimize angular dependency and short-shifting effects, ensuring consistent performance across various applications. Anti-reflection coatings maximize transmission in the visible (VIS) and near-infrared (NIR) spectrums, while double-side polished glass ensures exceptional parallelism and optical flatness. With a surface quality of 40/20 scratch/dig, these filters are durable and reliable. Available in wavelength ranges from 350nm to 1500nm, Longpass Filters can also be paired with Shortpass Filters to create custom, fine-tuned Bandpass Filters.
In-stock and ready-to-ship Longpass Filters are offered in multiple mounting and size options, including threaded mounts (sizes M13.25 to M105), 25.4mm C-Mounts, slip mounts, or unmounted formats. Custom shapes and sizes are also available to meet specific needs.
Longpass Filters are widely used in fluorescence applications to block excitation light sources or pass multiple emission wavelengths, significantly improving the signal-to-noise ratio. They are also popular in photography and astronomy, where precise wavelength control is essential for capturing clear and accurate images.
Shortpass Filter
Often referred to as “IR-cut” filters, Shortpass Filters are designed to transmit a broad spectrum of shorter wavelengths while blocking longer visible (VIS) and near-infrared (NIR) wavelengths. These filters are engineered with a sharp transition between the passed shorter wavelengths and blocked longer wavelengths, achieving peak transmission rates of up to ≥90% (85% for SP701 and 88% for SP705). With anti-reflection coatings for maximum transmission and an exceptional surface quality rating of 40/20 scratch/dig, these filters deliver reliable and precise performance. Available in wavelength ranges from 340nm to 785nm, Shortpass Filters can also be paired with Longpass Filters to create custom Bandpass Filters tailored to specific applications.
The SP Series includes filters optimized for different needs. VIS-pass filters are ideal for separating colors in monochrome or color applications, enhancing contrast and resolution. NIR-block filters are commonly placed over camera sensors to block NIR light, ensuring natural color rendering. They can also function as hot mirrors, reducing unwanted heat build-up caused by IR radiation.
Shortpass Filters are available in various mounting and size options, including threaded mounts (sizes M13.25 to M105), 25.4mm C-Mounts, slip mounts, and unmounted formats. Custom shapes and sizes are also available to accommodate specific application requirements.
These filters are widely used in color imaging to achieve accurate color reproduction. They also protect sensors from NIR laser damage and reduce IR radiation or “camera bloom” caused by hot metal or glass extrusion processes. Shortpass Filters provide a versatile and effective solution for demanding imaging applications.
Neutral Density Filters
MidOpt Neutral Density Filters act as "sunglasses" for your system, suitable for use with both monochrome and color cameras. These filters are specifically designed to diminish light intensity across a particular wavelength range without altering the image color or contrast. They are available in a variety of optical densities and allow for a reduction in light intensity while maintaining a wide aperture and a shallow depth of field, with each 0.3 density increment equivalent to one f-stop. By minimizing pixel saturation, these filters can also be stacked with other Neutral Density Filters to test different optical densities. They boast exceptional surface quality, featuring a 40/20 scratch/dig specification.
The ND Series, effective in the visible (VIS) spectrum, consists of absorptive filters functioning between 425-675nm and are offered in optical densities from 0.10 to 6.0. Meanwhile, the Ni Series caters to the broad spectrum, including both VIS and near-infrared (NIR) ranges, with low reflectivity and effective operation between 400-2000nm. These filters are available in optical densities ranging from 0.3 to 2.0 and are coated on low-expansion, heat-resistant Borofloat® glass.
Regarding mounting and sizing options, in-stock ready-to-ship Neutral Density Filters are available in Threaded Mounts ranging from sizes M13.25 to M105, as well as in a 25.4® C-Mount, Slip Mounts, or unmounted configurations. Custom shapes and sizes can also be accommodated. These filters are ideal for various applications, including imaging in intense lighting scenarios such as molten metal and welding, as well as outdoor aerial imaging and photography. Neutral Density Filters are instrumental in reducing shutter speed to introduce blur, thereby preventing a "jello" effect in aerial imaging.
Light Balancing
Light Balancing Filters are designed to correct artificial lighting, ensuring that colors appear more natural and balanced. These filters enhance color accuracy, eliminating the need for additional software processing, which contributes to improved image stability and control. They enable users to achieve precise color images when utilizing artificial light sources while also increasing contrast by correcting the emission spectrum of various lighting options. With exceptional surface quality featuring a 40/20 scratch/dig specification, these filters come in several series: the LA series reduces blue shading, effectively warming the scene, and is commonly used with white LED and xenon strobe lighting. The LB series is ideal for subduing the reddish hue often encountered with tungsten, halogen, sodium, and other light sources, while the FL series addresses the greenish cast produced by fluorescent lighting.In terms of mounting and size options, in-stock, ready-to-ship Light Balancing Filters are available in Threaded Mounts ranging from sizes M13.25 to M105, Slip Mounts, or unmounted configurations, with custom shapes and sizes also offered. These filters find practical applications in various color-intensive fields, including machine vision, factory automation, photography, and fluorescence imaging.
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