Fog of war

How can I change how much fog of war a specific unit type "unfogs"? By unfogs I mean how much of the surrounding area which previously was fogged turns visible. I guess it would be fine to change it for a specific unit as well or for all units if the former can't be done.

In the stats area, near the bottom of a unit's editing fields, there's field of vision during day and night. They're numbers that look like 1800, 1200, 1000 during day and 800, 600 during night. Different numbers on night elf and critters, and they're paired.

Thanks but I already tried changing those numbers but it doesn't seem to have any effect. Even if I set it to 0, 10 or 100, like 2 seconds after a unit gets relatively close (say 300 range) to a fogged area, a really big area is unfogged. EDIT: Never mind it seems it was an ability the unit had's (Blink maybe?) fault.

Also, when a unit is attacked, that reveals more fog to reveal the attacker (if within a certain range).

My problem was similar. The ability that caused my problem was the unit's inventory. This made a shop in the fogged area visible when the unit was in range. I've "fixed" the problem by moving the shop further into the fog and decreasing it's sale range. If there is a better solution (so the shop can have big range but not reveal the fogged area) I would like to know.