Distance, lighting (when do most big animals move), weather, shot window, lighting again (position of the sun and glare), gear (big glaring lens 15 pounds or so on a tripod or monopod versus swinging up a rifle or bow, Air quality, movement, composition. Those are just some quick things that come to mind. That's all after finding/spotting a Booner where there is hunting pressure from when Sept to December at best, and that doesn't include poaching or tribal harvest.