OptiFog was the old equivalent mod of OptiFine released by sp614x (creator of OptiFine, OptiFog and OptiMine). This mod optimized fog, boosted render distance and boosted FPS. After the creation of OptiFine, most OptiFog's features were put into OptiFine.
History[]
OptiFog was created in 2011 during the time of Beta 1.4.
In Beta 1.5, it recieved compailityble with both Optimine and ModLoader. In Beta 1.7.3 the last OptiFog version was released even though it wasn't supported anymore. With the combination of 3 mods (OptiFog, Optimine and Lag Spikes of Death), OptiFine was created. After the release of OptiFine, OptiFog was discontinued and Optimine was discontinued in next Optifine release too.