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Message: <blockquote data-quote="Kevin Purcell" data-source="post: 1263085" data-attributes="member: 68323">Is there an emoticon for pickyness?The resolution (sharpness) doesn't change as the contrast is reduced but the acuity does.Of course the effect is the same ... you can't see the damn bird properly.It seems a lot of people on this forum use these terms interchangeably though they aren't the same problem.I'd group "glare" and "stray light" together as a general reduction in contrast coming from light that outside of the desired image. You can verify this by using a hand to screen the light from falling on the objective. I notice this with some of my glasses (e.g. Minolta Compact) in overcast skies but it's much less of a problem in sunny skies. In cloudy skies there are more directions the light can come from to hit just "right" and spoil the contrast. THe effect is as Henry describes it an overall washout of the image with a brighter crescent, in this case at the bottom of the image from the clouds above.Of course glare also has some other common meanings<a href="http://en.wikipedia.org/wiki/Glare_%28vision%29" target="_blank">http://en.wikipedia.org/wiki/Glare_(vision)</a>"flare" is a different problem. It's related to the reduction in contrast in the dark parts of the image from bright light inside the image e.g. looking for plumage details in a bird sitting on a branch with sky or bright cloud behind it. With more flare the light gets scattered between the lens and is noticed in darker parts of the image reducing contrast (and so acuity). Lens and prism anti-reflective coating are the techniques used for reducing flare. The better the AR the less the flare. In less well coated lenses you'll see flare as bright spots and rings.Wikipedia has a good article (with pictures) on lens flare<a href="http://en.wikipedia.org/wiki/Lens_flare" target="_blank">http://en.wikipedia.org/wiki/Lens_flare</a>But bins with flare are great for UFO hunters<a href="http://valuca.piczo.com/LensFlare" target="_blank">http://valuca.piczo.com/LensFlare</a>Perhaps there should be a birdforum glossary (in the wiki?) that defines each of these terms. Or does that seem way too organized <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite2" alt=";)" title="Wink    ;)" loading="lazy" data-shortname=";)" />EDIT: rereading the wikipedia article I see they define flare as unwanted light in the image from reflection or scattering in the optical elements and then say "When a bright light source is shining on the lens but not in its field of view, lens flare appears as a haze that washes out the image and reduces contrast.". I guess we just need to get people to define their terms. Or at least use the phrase "stray light" for that type of problem.Of course if we use "barndoors" on our bins then the problem will go away. THis is a bit of a joke but adding len shaes (made from black pipe) to the ends of the objectives you could easily reduce this problem.And "veiling glare" is yet another term for it as shown (and measured) by this rather excellent page (and not because he uses the terms "flare" and "glare" the same way I do).<a href="http://www.imatest.com/docs/veilingglare.html" target="_blank">http://www.imatest.com/docs/veilingglare.html</a>I wonder if flare (i.e. dark image detail in a bright image) is another area where a porro prism bins can beat roof prism bins at a lower cost by reducing the number of air/glass transitions? Or do modern multi-layer AR coatings make this a moot point?</blockquote>

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