After feedback from users about difficulties with alignment trough a lens and the test results that are not satisfactory (high deviation due to light scattering trough the lens), you can now close the aperture slightly (the more you close the harder to align) and press the shutter button in the camera’s “bulb” mode. Hold the shutter pressed and align the light source until the display on the main screen shows “OK”. Then keep the light source in place and switch to the desired speed to test. This will ensure that the sensor receives enough light and the test can be carried out correctly.