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Message: <blockquote data-quote="OPTIC_NUT" data-source="post: 3219002" data-attributes="member: 121951">Aha!I suspected a similar behavior in a low-power telescope I made from bino parts with a large exitpupils for cameras.Sure enough, my "big can" monocular is fuzzier in the centerand never fully sharpens.   The issue is, the field lens in the EPis set for a wide-angle 7x35, but the objective is 50mm.To see if it's a matter of your optical train not being 'tuned' right,focus on something, one side, and pull your eye back 2-4 inches.Now move your eye a little bit up/down and left/right..if the field lens (counter)-aberration doesn't match the objective,you will actually see the center swim around spatially relative to therest of the image. The fuzziness will also be more obvious.A properly-made system has a steady image that stays cleanand undistorted as you approach the EP.    Some binocs. are actually madeso your eye has to be at a very specific place, so it might be worthtrying things with your eye closer and farther away.So....I realize now, that's a possibility, a mismatched EP and objective.It doesn't matter with telescopes, but binoculars are so short...Lucky for me the camera likes the mismatch.It may have its own issues that close to the EP.My eye, on the other hand, sees a little fuzzy Morrocan belly-danceunless I move it in.</blockquote>