LP830
IR Longpass Filter

Midwest Optical normally recommends the use of an LP830 filter in many cases, simply because when LED lighting is chosen for illumination purposes, 90% of all applications is either 880nm or 850nm LED lighting. We recommend the LP830 filter for 880nm when the choice of IR lighting will be made at a later time.

A longpass filter is sufficient for most IR lighting applications. Since ANY camera's sensitivity is dropping quickly beyond 880nm, there is little or no appreciable benefit to blocking these longer wavelengths. The camera is taking care of this by itself.

For this same reason, we recommend the LP830 longpass filter over the LP850 for 880nm LED lighting applications. The LP850 does not reach peak efficiency at 880nm, and the better transmission (over the better blocking of the LP850 filter) makes LP830 the filter of choice.

MidOpt single substrate filters are supplied with hard-coated surfaces to improve transmission and inhibit staining. Staining is a problem common to infrared filter glasses that can be found particularly on unprotected polished surfaces. This problem manifests itself as a cloudy, white film that etches into the polished glass. Over time, staining can greatly reduce transmission and resolution, and cannot be simply wiped away. Factors determining the time required and severity of staining include the year-round heat, humidity and air quality of the surrounding area. In certain environments, coatings are an absolute necessity.

Example:

(left) Glue bottle under white light and through a monochrome camera, looking for presence of batch code in lower right of bottle.
(center) 880nm LED illumination improves contrast.
(right) MidOpt LP830 creates much greater contrast and fully isolates the code.

More Examples of filter effectiveness.

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 830nm and above
Absorbs 815nm and below

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

95.60
95.62
95.70
95.74
95.88
95.94
96.03
96.13
96.21
96.26

96.33
96.39
96.41
96.50
96.44
96.52
96.61
96.59
96.69
96.80

96.81
96.58
96.20
95.54
94.16
90.79
83.62
69.58
47.90
24.99

9.57
2.89
0.76
0.20
0.06
0.02
0.01
0.00
0.00
0.00

0.00
0.00
0.00
0.00
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