Dense Cloud Not Using All Cameras?

[StevenF]

When I click on a point and select "Filter Photos by Point" I get a list of 17 photos, but when I run Build Dense Cloud over the same area the console readout says: "Selected 7 cameras."
Why is PhotoScan not including all cameras that overlap the region when building the dense cloud?

[Alexey Pasumansky]

Hello Steven,

If the number of matches for any pair of images is too low such pair will not be counted as overlapping and depth maps for this image pair will not be estimated.