I bought recently a used Panasonic 7-14/4 lens which looks great optically and cosmetically. However, I am worried about a crunching, or grinding noise coming out of the lens when I zoom at about 12mm. Also, the noise when auto-focusing is louder than my other m43 lenses. I've noticed some pre-release reviews on sites, like the Field Test on Adorama, and the test at whatcamera . com have noticed a zoom (but no auto-focus) noise, whereas later reviews everywhere notice how quiet the lens overall is. I am wondering -- do I have an early, or maybe even slightly defective sample which will get worse over time? How is the noise on your lens? Is there a way to find out a time code to see when the lens has been manufactured? Thanks for any insight.