Photometers: Accurate testing of luminous intensity

In the workplace, photometers are used to regularly measure the light intensity. This is intended to ensure that the distribution of lighting and its intensity in the relevant workplace are correct and that the lighting conditions there are optimal. Employees in a company can only work efficiently if their working environment is sufficiently illuminated. It is also a question of safety, because only with sufficient light intensity can errors in the operation of machines and systems be prevented. In addition, fatigue is reduced if the light in the workplace is appropriately bright. Photometers are therefore used to measure the following criteria, as well as others:

  • Lighting distribution and intensity in the workplace
  • Optimal lighting conditions in public buildings
  • Light distribution measurement at trade fairs and exhibitions
  • Good machine illumination in production


  • testo 545 testo 545

    testo 545 - Digital Lux meter with App connection

    Order-Nr. 0563 1545

    incl. GST  $922.90
    • Simple, fast and precise measurement of illuminance (Lux) according to the V-lambda curve for all common light sources
    • Wide range of applications due to LED compatibility (except single-colour blue LED)

Your ideal light meter – from the entry level to the professional model

Lux meters with permanent probes

Particularly easy operation due to compact, handy design.

Lux meters with connectable probes

Lux meter
In addition to light, also measures further parameters relevant to ambient conditions – simply attach the required probe.


Measure the light intensity
Lux probe for measuring illuminance – compatible with your lux meter with connectable probes.

Data loggers

Light meter
Monitor lux and other parameters via WiFi and store them in the Testo Cloud.

Lux meter with permanent probes

Lux meters with connectable probes


Measuring luminous intensity: Photometers for all requirements

Measure illuminance

Can lux be measured? Photometry has the answer to this question, with a photometer being the perfect tool for the job. One lux means that a luminous flux with the power of one lumen is uniformly distributed over a surface area of one square metre. A photometer is therefore also dubbed a “lux meter”, because it measures the illuminance. Different devices are available for all applications:

  • multifunction measuring instruments for measuring light and IAQ parameters
  • Lux meter with connectable probes
  • Photometer without interchangeable probes
  • Data logger for collecting and storing data

Indoor air comfort: Light

Testo's photometers are characterized by their compact design, and they make it possible to measure light very simply and within a very short time. The sensitive, high-precision sensors are adapted to the spectral sensitivity of the human eye or correspond to it. Thanks to the Hold function, the measured values are easy to read off. The large display also allows reading off from different angles. A photometer is used wherever it is important to have correct and sufficient distribution of light. Primarily in offices and in production, as well as in assembly halls and medical facilities, the lighting of a room or special area is of particular significance. Testo photometers measure light intensity and distribution with great precision and within seconds. Spot measurements are therefore also possible.

Photometers: Important specifications for high-precision instruments

The sensor plays a key role on the photometer. This is because its job is to perceive the light in the environment in a way that it can also be perceived by the human eye. The sensor must therefore perceive yellow and green light better than red or blue light. Other criteria for photometers are:

  • Well-structured operating menu
  • Intuitive operation
  • Large display
  • Assessment according to the V-lambda curve

Light meter: An indispensable aide for ensuring occupational health and safety

Lux meter

It is the job of the occupational health and safety department to ensure that eyes are also protected. These are often subjected to heavy stress in the workplace, which can be caused by computer work in the office or by varying lighting conditions in the production hall. The photometers are used to ensure that legal standards and specifications are being complied with. If everything is known about the existing lighting conditions, these can be adjusted according to the legal limits. In parallel with the photometer, a sound level meter is often used in the workplace, because volume also plays a key role when it comes to health and efficiency in the workplace.

More instruments for monitoring the workplace

In addition to the aforementioned sound level meters, an rpm measuring instrument can also be used. This complements the photometer and is suitable for measurements in production and air conditioning technology.

The CO measuring instrument also works with sensitive sensors and can detect even small concentrations of toxic carbon monoxide. If room air needs to be permanently monitored, the CO₂ measuring instrument from Testo is the ideal solution. In conjunction with the photometer, this measures the conditions in the workplace and thus ensures that changes can be made. Because you can only do something about bad figures when you know that they exist! If you know that the office is too dark or too poorly ventilated, you can search for solutions relating to the room's technology and architecture and offer your employees better conditions. In libraries, galleries and museums too, it is important to keep an eye on all the IAQ data, CO readings and luminous intensity in order to protect fragile objects.

Light meter: Built into the WiFi data logger

Photometers can measure luminous intensity. However, if they are to be stored and made available for an extended period of time, it is advisable to record the measured data in the data logger. Not only is it possible to measure light, but other data such as temperatures, humidity and UV radiation are also recorded. At Testo, data can be stored in the Cloud. Photometers are also available with external probes. The required probe, which, for example, is to be used to monitor extremely light-sensitive objects in an exhibition, is connected to the data logger. The readings are processed in the probe, which is extremely high-precision.