Here's a few real world pictures where you may or may not see VPN. These are JPEG's straight from the camera except for the resizing. The VPN is definitely visible if you increase the brightness / exposure, but I think whether you see it in these pictures depends a lot on your monitor and ambient light levels (it'll be more visible on the 1800x1200 images).
K10D | 21mm | f/3.2 | ISO 800 | 1/4 sec |
1800x1200
K10D | 21mm | f/3.2 | ISO 800 | 1/5 sec |
1800x1200
K10D | 21mm | f/3.2 | ISO 1600 | 1/5 sec |
1800x1200
K10D | 21mm | f/3.2 | ISO 800 | 0.6 sec |
1800x1200
K10D | 21mm | f/3.2 | ISO 100 | 5 sec |
1800x1200