The lowest exposure time that can be manually set using the relevant slider is 1/25 second. Several QCUIAG members have - individually or inspired by others - discovered that it is possible to 'trick' the Vesta into the slower exposure time of approximately 1/5 of a second.

Here is how to do it and how to verify that you succeeded.

SETTING TO 1/5 second
1. Launch your Vesta as usual
2. Set fps to 5
3. Set exposure to "auto" (tick box)
4. Cover the lens opening for 5-10 seconds. During this period the camera - in automatic mode -changes the shutter speed below the "normal" limit of 1/25 second.
5. Turn off "Auto" exposure.
6. Click "Save" under Defaults.
7. Now you can uncover the lens opening.
8. Done. NOTE: the slider indicates 1/25 second, but this is not true.

USING THE 1/5 SECOND EXPOSURE
1. Launch your Vesta as usual.
2. Set fps to 5
3. Click "Restore" under Defaults. (Note: the saved/restored defaults do not change the fps rate.)
4. Now the 1/5 shutter speed has been restored. WARNING: using the exposure slider destroys this setting immediately. In that case repeat step 3 to reinstate. Brightness and gain can be set at will.

VERIFYING THAT 1/5 SECOND EXPOSURE IS ACTIVE
1. Launch your Vesta as usual
2. Set fps to 5
3. Turn on "Auto" exposure.
4. Turn off "Auto" exposure.
5. Slide the shutter speed to 1/25th, observe the brightness of the image, clicking Restore (meaning the setting you created in step 1) and: you will see a big change in lighting before and after the Restore button.

The above procedure is applicable to the Philips Vesta Pro cameras.
For the Philips ToUcam Pro cameras (also model II) please see Matthias Meijer's findings, while another set of tests has been performed by Peter Katreniak.