Canon Lens USM Adjustment
Affordable Frequency Counter Solutions
To adjust the USM motor in Canon lenses using Canon Lens Professional, you'll need a Frequency Counter. These used to be pricey, but now you can get one for a reasonable cost.
The Frequency Counter mentioned below was bought from Component Tester on eBay for $14.00. You can also find them available at other retailers.
This great tip is from Greg Sugrue / C W Services Ltd. / NZ