BP850
Infrared Bandpass Filter

Recommended for use with high-power IR LEDs

To significantly improve and maximize contrast when working in the infrared, the use of a filter is almost mandatory. And when high-power LED lighting is being used, MidOpt recommends the use of our BP850 filter.

High transmission and broad bandwidth

In well over 90% of all infrared inspection applications, 850nm or 880nm LEDs are employed. We often suggest our single substrate, hard-coated BP850 as it offers very high peak transmission (typically >99%) and the coatings used are very dense, hard and environmentally stable.

While this filter's bandwidth is quite broad, ANY camera's sensitivity drops quickly beyond 880nm so there is normally little appreciable benefit in blocking these longer wavelengths... the camera sensor essentially takes care of this all by itself. 

BP850 filter contrasted with typical 850nm LED output and CCD spectral sensitivity.

Resists staining

MidOpt IR filters feature fully-coated surfaces that improve transmission and inhibit staining. Staining is a problem common to almost all IR filter glasses if they have unprotected, polished surfaces. The problem manifests itself in time as a cloudy, white film that etches into the polished glass surfaces. Over longer periods, staining can greatly reduce transmission and resolution, and cannot be simply wiped away. Factors determining the timing required and severity of staining include year-round heat, humidity and the air quality of the surrounding area. In certain climates and environments, protective coatings are an absolute necessity.

Example:

(left) Monochrome image in white light shows too much information.
(right) BP850 is used to block out unwanted elements for simple reading.

More examples

Download Excel Spreadsheet with data and curve for this filter.

Standard Threaded Mounts:
We offer standard filter sizes from stock – 22.5mm to 62mm – for same- or next-day shipping. Larger filters – 67mm to 105mm – are made to order and are normally not returnable.

Click here for PDF drawing of standard mounts

Slip Mounts:
If your lens does not have threads for mounting a filter, Slip Mount adapters are available. Slip Mounts can attach a regular filter to a lens or attach a very large filter to accommodate a wide angle lens. Please call to order Slip Mount adapters.

C-Mounts:
3mm thick threaded mount for adding a filter between lens and camera
Click here for PDF drawing of c-mounts

Transmission chart (typical)
Passes IR 810-990nm
Absorbs 200-800nm
Reflects 1010nm and above

1100
1090
1080
1070
1060
1050
1040
1030
1020
1010

1000
990
980
970
960
950
940
930
920
910

900
890
880
870
860
850
840
830
820
810

800
790
780
770
760
750
740
730
720
710

700
690
680
670
660

18.52
20.08
21.89
24.05
26.69
29.86
33.67
38.23
43.57
49.66

56.47
63.93
71.76
79.39
86.16
91.73
95.60
98.09
99.39
99.55

99.76
99.95
99.76
99.51
98.49
97.71
95.47
91.21
83.94
72.74

57.66
40.40
24.82
13.24
6.43
2.94
1.36
0.66
0.35
0.20

0.12
0.08
0.05
0.03
0.00

650
640
630
620
610
600
590
580
570
560

550
540
530
520
510
500
490
480
470
460

450
440
430
420
410
400
390
380
370
360

350
340
330
320
310
300
290
280
270
260

250
240
230
220
210

0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00

0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00

0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00

0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00

0.00
0.00
0.00
0.00
0.00