The Dense Cloud quality setting controls at which size the source images are used:
Ultra = full size
High = Downscaled to 50%
Medium = Downscaled to 25%
Low = Downscaled to 12,5%
Lowest = Downscaled to 6,75%
Please also see this thread:
http://www.agisoft.ru/forum/index.php?topic=1741.0I would still like to see a custom setting, where I can just fill out 75% for example. Some of my projects are getting too big on Ultra, and have too few points on High. Of course I could scale my source images, but having a scaling setting in Photoscan would be much faster.