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Message: <blockquote data-quote="henry link" data-source="post: 2948276" data-attributes="member: 6806">I've posted many times on this subject, so I won't re-hash everything. Here are the basics of what I've found from examining binocular interiors under the conditions that cause these things. Nearly everything that is called glare, flare, veiling glare, haze, etc. is caused by glancing reflections from lens edges or the metallic surfaces of objective lens cells, focusing lens cells or prism shelves. The left photo below shows an example of what that looks like - a fuzzy haze of light overlaying the image, sometimes looking like an unfocused crescent moon near the edge of the field. The middle photo shows the cause - objective lens and focusing lens cells inadequately baffled against a very bright off-axis light. In this case the source of glancing light is so bright that it even causes some back reflections from lens surfaces (the colored reflections) and lights up every dust mote on a relatively clean objective lens. The only reflections that contribute much to the fuzzy haze on the image, however, are the bright ones coming from the bottom edges of the lens cells (blown-out from overexposure in the photo). Occasionally there are similar reflections coming from the edges of eyepiece lenses or spacers between the eyepiece fieldstop and the eye. They can cause a ring of defocused reflections in the black area just outside of the image field, but not typically within the FOV.The right photo shows ghosting in a binocular. In this case the ghosts are the dim "triangles" scattered around the field. They are duplicate images of the brightest parts of the very bright halogen lamp light source on the left. We birders don't see much ghosting under daylight conditions, but it can be a problem in astronomy for a few bright objects like the Moon, Venus or Jupiter. It's caused when a glass surface reflects forward to another backward facing glass surface and then back to the eye.Another reflection problem I've noticed mentioned happens when there is a bright light source behind the observer, which reflects from the eyepiece glass backwards into the eye. I think the term "ghosting" should be limited to what it really is. As for all the the other glare/flare terms, I prefer "veiling glare", but the term used is less important than understanding the causes.</blockquote>

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