Color and polarization lens filters
Lens filters for c-mount lenses (bandpass, longpass)
Lens filters, like a bandpass filter or longpass filter are placed on the front of a machine vision lens. The lens filter, blocks certain wavelengths of the light (color), making sure that only the required light wavelengths will be captured by the machine vision camera. The lens filter can also be used as a protective cover for the lens.
In our article “How to use (color) C-mount lens filters” we explain how you can get more contrast in the image by using the correct color or polarization lens filter.
Different types of lens filters, bandpass and longpass filters
There are four types of lens filters:
- Bandpass filter (BP filter). Only a specific light wavelength (for example blue light, red light, green light) will pass the light filter.
- Longpass filter (LP filter). Only light starting from a specific light wavelength will pass the filter. As example, the LP420 passes all wavelength above 420nM (Blue + green + red + infrared) and block all wavelengths below 420nM (like UV light)
- Shortpass filter (SP filter). Only light till a specific light wavelength will pass the filter. As example, the SP420 blocks all wavelength above 420nM (Blue + green + red + infrared) and passes all wavelengths below 420nM (like UV light)
- Special filters. These filters allow specific parts of light wavelengths to pass and block. As example the UVIRCUT. This filters blocks all UV and IR light, but passes all visible light.
Mounting a lens filter, bandpass and longpass filters
Machine vision lenses have a filter thread that is used to screw the lensfilter on. Large lenses have a different filter thread then compact lenses. The most common size for a lens filter are:
- M25.5xP0.5
- M27xP0.5
- M30.5xP0.5
- M35.5xP0.5
- C-mount filters, which are screwed inside the C-mount of our USB3 cameras or GigE cameras. The C-mount filter is placed between the camera and lens, making it an ideal solution when a lens without filter thread is needed.
Not all our machine vision lensfilter are online as seperate products, therefore on this page you can customize your own lensfitler by selecting the desired bandwith and size. If you need help to select the most suitable bandpass / longpass / shortpass lens filter for your application, feel free to contact us.
