LMK 6 color

luminance measuring video photometer
LMK color

The LMK 6 color uses a color glass filter wheel to match the CIE color sensitivity functions of the 2 ° standard observer (CIE 1931). Each camera comes with an unique color filter wheel, which ensures a high quality of customization and focuses on the unique spectral CMOS sensitivity function. The LMK 6 color is critical for imaging color and chromaticity measurements in addtion to imaging luminance measures.

In addition the measuring system can be equipped with other full-glass filters. For example, the scotopic sensitivity V '(λ), the circadian response function C (λ), the spectral action function for melatonin suppression Smel, different NIR filters, a BLH filter (blue light hazard), or a glass filters are available.

The LMK 6 color is robust in construction, lightweight and has compact dimensions. This means that it can be used in almost every process for many different light and color measurement tasks.
In conjunction with the supplied system and measurement software, the LMK6 color can be used in areas of application where the imaging determination and evaluation of luminance and color distribution is required.

A large selection of high-quality standard lenses and special imaging systems in combination with an interchangeable lens mount further increases the flexibility of the LMK 6 color. As a result, the LMK 6 color is able to meet many requirements and combines a wide range of measuring devices in a single system.

Flicker detection

With the use of a CMOS image sensor array, it is not necessary to transfer a complete image during image acquisition (global shutter). Rather, the CMOS technology makes it possible to partially read the image data. For example, individual image pixels or image lines (rolling shutter) can be recorded.
Using this option, it is possible to realize a very fast image capture.

For the flicker detection, 4 image lines with a total exposure time of 21μsec are continuously recorded and written to each other in a single measurement image. This makes it possible to show the periodicity of the input signal on the time axis.
With the aid of this evaluation method, the frequency and the modulation depth of the input signal can be determined.

If the option of flicker detection is activated for the image acquisition, the exposure time control of the LMK is automatically adjusted to the flicker frequency of the light source (DUT).

Flicker detection

Sensor - imaging CMOS matrix system
Standard resolution (LMK 6-5 color)
2464 x 2056 Pixel
Sony-CMOS [ IMX 250 (2/3"); 12 Bit digital ]
High resolution (LMK 6-12 color)
4112 x 3008 Pixel
Sony-CMOS [ IMX 253 (1,1"); 12 Bit digital ]
Measurement time
starting with 1 sec. up to 15 sec. depending on luminance level, adjusted lens and exposure/integration time
Dynamic range
[ 1:10000000 (~140 dB) ]
Data interface
Gigabit Ethernet Interface(GigE®)
Spectral matching
  • using V(λ)-function matched full glas filter for luminance measures
  • adapted with full glass filters to the X(λ)-, V(λ)- and Z(λ)-function to measure color values
  • further full glass filters for the functions C(λ)-, V'(λ)-, Smel and BLH (blue light hazard) as well as NIR filters are available

Metrological data

Metrological specifications
V(λ) [ f´1 < 4 %1]; X(λ) [ f*1 < 4 % ]
Z(λ) [ f*1 < 6 % ]; V´(λ) [ f*1 < 6 % ]
Measuring quantities
Luminance: L (cd/m²)
Chromaticity coordinates
Supported colour spaces
RGB, XYZ, sRGB, EBU-RGB, User, Lxy,
Luv, Lu’v’, L*u*v*, C*h*s*uv, L*a*b*,
C*h*ab, HIS, HSV, HSL,WST2
Measuring range (integration time)
100 µsec. ...15 sec.
Measuring range depending on lens aperture value (F)
1 msec. ... appr. 7500 cd/m² & 3 sec. ... appr. 2.5 cd/m² (F = min.)
1 msec. ... appr. 60000 cd/m² & 3 sec. ... appr. 20 cd/m² (F = max.)
Measuring range for the preset f-number (F/4)
1 msec. ... ca. 10000 cd/m² & 3 sec. ... ca. 3.3 cd/m²
Calibration uncertainty2
fix focused lenses ∆L [ < 2 % ]
focusable lenses ∆L [ < 2.5 % ]
∆L [ < 0.1 % ]
Measuring accuracy
∆L [ < 3 % (for standard illuminant A) ]
∆L [ < 2 % ]

Dimensions and weight

Housing dimensions without lenses
Housing dimensions LMK 6-5 color
stable black anodized aluminum housing: 117 mm x 90 mm x 47 mm (HxWxD)
Housing dimensions LMK 6-12 color
stable black anodized aluminum housing: 140 mm x 110 mm x 47 mm (HxWxD)
Weight LMK 6-5 color
camera housing without lens: 800 g

available lenses: 120 g - 600 g
Weight LMK 6-12 color
camera housing without lens: 1300 g

available lenses: 200 g - 800 g


  • Complex evaluation of luminous and illuminated scenes by means of the photograph of an image-resolved luminance distribution
  • Simultaneous recording of a large number of connected measuring data for easy data analysis (at a glance)

Result data

  • Luminance distributions in measuring images L(x,y)
  • Color and chromaticity distributions in measuring images
  • Derived lighting-engineering parameters such as illuminance distribution E(x,y) and luminous intensity distribution I(x,y)
  • Statistical data for use in various calculation programs (z.B. EXCEL®, MatLAB®, LabVIEW®)
1 Measurements according to DIN 5032 Part 6/CIE Pub. 69 | 2 Calibration according to DIN 5032 Part 6 using a luminance standard led back from the Physical-Technical Federal Institute | 3 Measurement performed on a stabilized white LED light source L=100 cd/m². Mean value over 100 Pixel; repeatability as variability of the mean value.