Spectroradiometer - Topcon SR-UL2

Topcon SR-UL2
Ultra Low Luminance Spectroradiometer

NEW PRODUCT ALERT – As of February 2022, the Topcon SR-UL2 has been replaced by the SR-5 Series. Please visit the SR-5 Series Product Page to learn more.

Reaching down to 0.0005 cd/m2, the Topcon SR-UL2 Spectroradiometer offers a further 2x improvement in low light sensitivity over the SR-UL1R. That means this spectroradiometer competes directly with the leading low light (PMT-based) photometers while providing the increased color accuracy and full spectral measurements available only in a diffraction grating and linear CCD based system.

The SR-UL2 provides increased color accuracy (±0.002 xy) and guaranteed accuracy luminance measurements down to 0.0005 cd/m2. The four standard apertures (2° / 1° / 0.2° / 0.1°) are automatically selectable by the control panel or through the USB / RS-232 remote interfaces (knob is eliminated) and allow you to optimize the measurement spot size (also a function of working distance) and the minimum measureable luminance level (larger apertures can measure lower levels).

With auto-sync measurements (for flickering light sources), programmable integration time, and a normal/fast mode, the SR-UL2 sets a new standard for full-featured, low-light (< 0.1 cd/m2) instruments.



Measure low luminance with accuracy

Measures luminance and color as low as 0.0005 cd/m2 with high accuracy


Luminance, spectral distribution, and CCT measurements

Supports Luminance, Spectral Distribution, CIE1931 and CIE1976 chromaticity coordinates, Tristimulus value XYZ, CCT and Deviation, CIE1976 L*a*b*, Eab*± , CIE1976L*u*v* Euv*±


Four apertures available

Four (4) apertures 0.1°/0.2°/1°/2° enable you to measure luminance from small to wide area without attachment lens


Luminance, Chromaticity, and Color Temperature measurement of LCDs, CRTs, OLEDs, LEDs, etc

Transmittance of LCD polarizing plates & filters

Luminance and color measurement of various light sources

Step it up

For a wider dynamic range, from ultra-low luminance of 0.0005 cd/m2 up to 500,000,000 cd/m2 consider the Topcon SR-5A Spectroradiometer. This ultra-sensitive instrument can measure high luminance while still providing greater sensitivity for measuring very low luminance levels with full spectral analysis.

Parameter Aperture
0.2° 0.1°
Optical System Objective lens: f=82mm F2.5
Eyepiece lens: View field 5°, Diopter adjustment range ±5 diopter
Measurement Distance 350mm – Inf.
Luminance Range cd/m2 0.0005 ~ 3,000 0.0015 ~ 9,000 0.0375 ~ 70,000 0.15 ~ 300,000
Spectral Range 380 ~ 780 nm range @ 1 nm resolution
Luminance Accuracy ±2% (for standard illuminant A)
Color Accuracy ±0.002 in 1931 CIE x,y Space
Spot Size at 1m 32.2 mm 16.1 mm 3.2 mm 1.6 mm
Min. Spot Size at 35cm 10 mm 5 mm 1 mm 0.5 mm
Dimensions Approx 406mm (L) x 150mm (W) x 239mm (H)

Ordering Information

The base unit model number is SR-UL2 and includes:

  • Instrument with standard lens
  • AC adapter
  • Lens cap
  • Hard shell carrying case
  • Manual
  • USB Cable
  • CD containing CS-900A software

See the SR-UL2 Brochure for available options. Popular options include:

  • AL-6 and AL-11 adapter lenses (for reducing the measurement spot)
  • Tripod and fine adjustment stand (gimbal)
  • Fiber optic probe

If you can’t find what you are looking for, contact us for info on Topcon options and accessories.

Want to find out more?

If you are interested in more information, send us an inquiry.