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Message: <blockquote data-quote="typo" data-source="post: 2127845" data-attributes="member: 83808">Rene,I guess we've been standing back waiting for the experts on the forum to post a definitive answer. In the mean time I'll have a go. There is a basic explanation here:<a href="http://www.monkoptics.co.uk/General/about-binoculars.html" target="_blank">http://www.monkoptics.co.uk/General/about-binoculars.html</a>Generally binoculars have a sharper focus in the centre on the field than at the edges. How rapidly the image deteriorates is an indicator of optical quality. Some designs may narrow the field of view to mask the deterioration, but typically sharp edges are expensive. However, this is easily confused with field curvature. In practice it means that the focal point at the edges of the field is closer than at the centre. Whether this is good or bad depends on personal preference. Those who like it might describe the view as having a greater depth of field, or a 3-dimensional view, though both are totally incorrect descriptions in this context. Those who don't like it may say the edges are fuzzy, hence the confusion. Many designs now have a field flattening or aspheric lens which will reduce the field curvature. So if you are standing square or to a target like a flat sided building then more (or all) of the view will be in focus. Getting this right without introducing other distortions is tricky and expensive. Most binoculars will have a certain amount of pincushion built into the design (check the link). The benefit is that when you move the binoculars from side to side the view appears more stable. Too much or too little can be nauseating for some, but not everyone notices it. The important thing is to try a lot of pairs and buy the one that you enjoy using. Trying to figure out why you like it can wait 'till much later. Most of us are still trying to work that out and is the subject of much debate here. Hope this helps. I'm sure the experts will pick up on any errors of mine or add more detail if required.David</blockquote>

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