MidOpt DB Series Filter DB475/850
Uniforce Product
Salient Features
Dual Bandpass Blue + 850nm NIR
DB475/850 Dual Bandpass Filter Visible Blue + NIR
- Useful Range : 460-490nm, 830-870nm
- FWHM : 45nm, 55nm
- Tolerance : +/-5
- Minimum Peak Transmission : ≥90%
- Surface Quality : 40/20
The performance of a filter is based on what happens to light passing through the filter. The apparent color of light reflected off the surface is not a reliable way to judge the filter’s capabilities. Batch-to-batch difference in the apparent color of the coatings or filter substrates can often be easily seen when looking at two examples of the same filter type. The color of the coating does not indicate a disparity in performance.
The DB475/850 Dual Bandpass Filter has been primarily designed for NDVI imaging applications. When using a single camera, incorporation of this filter allows reflected near-infrared light (850nm) to be captured in the camera sensor’s red channel and reflected blue light (475nm) to be captured in the sensor’s blue channel (the green channel is not used). Even when using an inexpensive consumer camera (that has first had its IR blocking filter removed), this easy separation then makes it possible to post-process the red and blue channels for NDVI by performing the calculation: NDVI = (red – blue) / (red + blue). Healthy vegetation will absorb (not reflect) blue light and strongly reflect near-infrared light. Thus this information can then be used to apply a false color gradient to images to better highlight the contrast between regions of healthy vegetation vs. areas with stressed/diseased or no vegetation.
DB475/850Transmission Data
| wavelength | transmission | wavelength | transmission |
| (nm) | (%) | (nm) | (%) |
| 1100 | 0.15 | 720 | 0.44 |
| 1090 | 0.05 | 710 | 0.2 |
| 1080 | 0.01 | 700 | 0.03 |
| 1070 | 0.04 | 690 | 0.07 |
| 1060 | 0.25 | 680 | 0.04 |
| 1050 | 0.14 | 670 | 0.09 |
| 1040 | 0.01 | 660 | 0.21 |
| 1030 | -0.02 | 650 | 0.08 |
| 1020 | -0.02 | 640 | 0.03 |
| 1010 | 0 | 630 | 0 |
| 1000 | 0.04 | 620 | 0.02 |
| 990 | 0.01 | 610 | 0.03 |
| 980 | -0.01 | 600 | 0.01 |
| 970 | -0.01 | 590 | 0.02 |
| 960 | 0.06 | 580 | 0.01 |
| 950 | 0.09 | 570 | 0.02 |
| 940 | 0 | 560 | 0.02 |
| 930 | 0 | 550 | 0.01 |
| 920 | 0.03 | 540 | 0.03 |
| 910 | 0.14 | 530 | 0.06 |
| 900 | 0.51 | 520 | 0.22 |
| 890 | 6.78 | 510 | 0.34 |
| 880 | 53.04 | 500 | 27.47 |
| 870 | 89.2 | 490 | 86.64 |
| 860 | 93.01 | 480 | 89.98 |
| 850 | 93.57 | 470 | 88.43 |
| 840 | 92.99 | 460 | 88.63 |
| 830 | 84.55 | 450 | 33.62 |
| 820 | 21.07 | 440 | 0.07 |
| 810 | 0.87 | 430 | 0.02 |
| 800 | 0.1 | 420 | 0.02 |
| 790 | 0.03 | 410 | 0.03 |
| 780 | 0.05 | 400 | 0.02 |
| 770 | 0.19 | 390 | 0.01 |
| 760 | 0.25 | 380 | 0.01 |
| 750 | 0.17 | 370 | 0 |
| 740 | 0.04 | 360 | 0 |
| 730 | 0.12 | 350 | 0.01 |
Available Mounts
Threaded Mount
- Designed for lenses with filter threads, a variety of filter types and stock threaded sizes are available: M13.25-M105
- Larger sizes, 62mm to 105mm, are made to order and are not returnable
- Custom thread sizes are available upon request.
- Threaded mounts are available as black anodized aluminum rings. Rotating mounts with locking thumb screws are generally provided.
Ordering Example:
- Filter: BP470
- Mount Size: M27
Correct Part# is:
- BP470-27
Threaded Mount Technical Drawing PDF
Slip Mount
- Designed for varifocal lenses, wide angle lenses and lenses without filter threads
- Accommodates standard threaded mounts
- Low profile and oversize diameter design prevents wide angle lens vignetting
- Locking set screws and a wrench are provided to secure the adapter to the lens
- Many varifocal and shorter fixed focal length (wide angle) lenses are not supplied with filter threads due to the presence of a protruding, strongly convex lens element. Our slip mount adapters allow standard threaded filters to be fitted securely to these and a large variety of lenses that do not have filter threads provided.
Ordering Example:
- Filter: BP470
- Outside Diameter of Lens in mm: 43mm
Correct Part# is:
- BP470-S43
Slip Mount Technical Drawing PDF
C/CS Camera Mount
- Designed to thread directly into any C/CS mount camera between the lens and sensor
- Wrenching slots aid in threading the filter into the camera body. A wrench is supplied with each filter.
- Helpful in applications with space constraints
- Can be used with wide angle lenses that do not accept filters at the front end to prevent vignetting
- C/CS mount filters are available in a standard 1mm thickness
Ordering Example:
- Filter: BP470
- Mount Size: 25.4
Correct Part# is:
- BP470-25.4
C/CS Camera Mount Technical Drawing PDF
Unmounted & Custom Size
- Any MidOpt filter type can be provided as an Unmounted filter
- Custom shapes and sizes are typically fabricated with one day to two week lead times
- Custom filter types with longer lead times can also be quoted. Please contact us regarding feasibility.
Learn More About
› Learn More About Day/Night Imaging in Color Applications
› Learn More About the Use of Dual Bandpass Filters in NDVI/Agricultural Inspection
