Also, is this in perfect light or near dark conditions?
It's during daylight hours and in the woods condition, shade/light etc....
Low light, yes this does make a difference in visual degredation.
Oh and by the way Rob, do you think it helps your groups due to the fact you are shooting at a target with a white background and not picking a spot on a brown/grey deer?
Not really, I can shoot those same groups aiming at a hole in the deer/target if a spot is visually bright enough ie contrast etc. Many times I'll sink the first arrow and then aim for that arrow depending on distance shot. Again, I don't like busting expensive arrows.
I also believe if we would all practice shooting at a more lifelike target(including real deer hair color) in early morning/late evening shade, we would begin to find some inconsistency in our shooting. I know I did. A lot of difference in that and shooting at that whit or yellow bag with the black dots. JMO
I haven't found this to be exactly true. If you take out the equation of color or target make up/form and aim for the mark/intended target. In 3D tournaments that might be a nock, a former arrow hole, a ring, a shaded/sun mark etc...I don't see a deer/turkey/elk/caribou. I only see a mark....thus picking a deers hair, ruffled hair, discoloration etc...
A mark is a mark be it a round circle on a white morrell bag or a black hole in a 3D deer. If you can see the mark, I intend to hit the mark, not an area.
Thus, it's easier to hit the center of a golfball than it is to hit the center of a basketball. Aim small, miss small etc...