DIY Laser levelling using webcam and laser level

[Sasquatch]

Did anybody test flatness of the laser beam yet? I'm impressed with results you're getting and just that one question remains unanswered.
I have garde 00 600x400 mm granite plate, one diagonal(720mm) is within 1 micron.
SJ4000 with large sensor and high resolution and can act as webcam.
just no laser...checking ebay...

[John McNamara]

Hi Sasquatch

If you study the two test series I did with two different sensors you will see that the resolved measurements taken with the second sensor were better with the higher density (The pixel lines were closer together), sensor used for the second set of tests.

No lens was used just the wire shadow.

Devmonkey mentioned that the results were better without a lens when he did tests with a laser. Using a lens with the laser generated distortion? I can also confirm this when I tried using a laser with a lens.

Maybe the standard lens supplied with a webcam or action cam is not the ideal for working with a laser. I know industrial laser cutters use lenses made from Germanium and other exotic materials.

A friend who spent his working life as a physics lab tech also mentioned that webcams will probably have a red filter behind the lens and in front of the sensor. He suggested that this should be removed if working with laser light.

These are only study notes on my part, I wish I knew more about optics. Maybe one of the MYCNCUK members here can give a more qualified view?

Regards
John