You can get one like this from Astro gears
http://www.tan14.com/Others.htm
Webcam 1.25"adapter . . . HK$50 (in stock 現貨)
- M12 x 0.5mm thread, fit for Philips and other webcams
- With 1.25" filter thread
http://www.tan14.com/images/adapter.JPG
With 1.25" filter thread