How far can ants see?
Dear Straight Dope:
How far can an ant see? Don't dance around it, and give me all the nonsense about their eyes being different. In terms of distance, how far can an ant see? Across a room? Only two feet? What?
Well, it's very hard NOT to dance around this, because their eyes are different. But if you want literal, I can give you literal. In terms of distance, an ant can see the sun, just like you can. That's what, 93 million miles away?
Now that that's dispensed with, I assume you meant "a focused image"--but that's something that isn't possible given the nature of the insect compound eye. Ants don't HAVE a focal distance, since they don't have a lens and retina arrangement, so the question requires dancing around. The best answer, then, is that an ant (or any insect or crustacean with compound eyes) can presumably see exactly as well as a digital camera that has only a few thousand pixels resolution, so distance from the eye is irrelevant. Each individual facet of the compound eye corresponds to a single pixel. That's not going to be a very detailed image, no matter what. Something like a dragonfly or horsefly, on the other hand, has tens of thousands of facets, giving much better resolution. Ants are toward the low end of the scale in that regard, and some, in fact, are totally blind.