SP730
Hot Mirror/NIR Colorless
Blocking Filter

The single substrate, hard-coated SP730 filter is suggested for color imaging applications where the camera is not supplied with an infrared blocking filter.

Also known as a "crystal clear" hot mirror because there is no attenuation of the visible spectrum, the results are excellent color rendition. A very small portion of near-IR and UV are passed to insure that no deep blue or deep red wavelengths are sacrificed.

This dichroic filter is hard-coated on a low expansion glass, therefore heat resistance is excellent.

The infrared spectrum is usually defined as starting at 700nm. Depending on the spectral response of any given camera, some camera manufacturers feel they achieve a much better color balance when they are able to truly pass ALL of the visible light that their COLOR camera is sensitive to. The deep red portion of the visible spectrum is essentially not affected, thus the 50% point for this IR blocker is at 730nm. Infrared blocking over the 750-1100nm range is better than or equivalent to that of any standard IR blocking filter in use by most camera manufacturers. Average visible transmission exceeds 95%.

Certain machine vision filters can also be used to block the bright glow of hot metals, glass and other material. Shortpass filters allow light up to a specific wavelength to pass through while blocking all light at higher wavelengths. This useful feature permits, for example, the viewing of hot rolled steel to see certain temperature areas while not blinding the system from the brighter, hotter areas.

See SP510, SP570, SP585, SP625, SP645, SP700 and SP730

Download Excel Spreadsheet with data and curve for this filter.

Examples of filter effectiveness.

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 370-725nm
Reflects 735-1100nm

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

1.61
1.44
0.76
0.37
0.20
0.13
0.11
0.10
0.11
0.16

0.30
0.98
2.55
0.85
0.40
0.32
0.42
0.96
3.35
1.65

0.65
0.51
0.67
1.23
1.42
0.78
0.58
0.65
1.07
1.97

1.82
1.58
2.26
5.19
9.85
11.61
20.16
54.70
89.80
89.12

80.57
83.22
94.81
96.25
92.95

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

94.50
98.03
94.30
97.71
98.08
97.91
97.07
97.12
96.41
97.35

98.37
93.80
98.24
96.80
95.90
96.63
93.44
95.92
96.23
95.74

93.97
86.09
92.23
91.32
91.26
85.37
80.02
81.34
71.19
1.48

10.76
2.35
0.09
0.02
0.01
0.00
0.00
0.00
0.00
0.00

0.00
0.00
0.00
0.00
0.00