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Message: <blockquote data-quote="typo" data-source="post: 3199727" data-attributes="member: 83808">Brock,I'm not sure I wan't to get involved in this discussion. It's been churned over countless time since I joined the forum and it seems to have made little difference to entrenched opinions. For that it's worth this is the way I understand it.The "Depth of Field" is the range of acceptable focus. Optically it is affected by distance, aperture and magnification. There is a complication that when using an eye rather than a camera sensor you need to factor in accommodation and the pupil of the eye governing the effective aperture. So if the conditions are the same all 8x etc. will have the same depth of field. It's probably easier to understand this if you consider only the very centre of the view in the first instance.Using two eyes doesn't change the DOF, it allows "Spacial Positioning" or stereopsis. The user is able to perceive where in three dimensional space an object is. Separating the objectives allows the brain to do so at longer range. It does not change the DOF but allows the user to judge the relative distance of those limits.Factors such as field flatness or curvature, the degree of astigmatism or afocal blur in the periphery of the view alter how much of the view is in focus and where that focus occurs in a three dimensional space. A curved field allows close features to be sharp at the edge as well as more distance objects at the centre. This can give the impression of greater range of focus or perceived volume of focus though it's actually an illusion. This is not the same as a greater DOF as the same rules for dictating DOF apply at the edge of the view as the centre. There are other more complex stuff stuff that probably be thrown in the mix but I think that is enough for now.So DOF, stereopsis, focal distance and the perception of focal volume are quite separate properties of the binocular and the user experience. The disagreements seem to occur when some use DOF as a term to cover everything.David</blockquote>

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