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Message: <blockquote data-quote="Troubador" data-source="post: 3169605" data-attributes="member: 109211">SteveYours is a great question. And I am sure there is much to this than simply saying well its SP prism bins design, thats it, nothing more to do or discuss.I'm making this up as I go along because I am no optics designer.Lets say you come at this from wanting to design an ultra-compact bin.So you want a short length.This means you have to achieve your optical path within a shorter distance, so I guess that means you need glass types with a higher refractive index to make more 'powerful' lenses. The various combinations of lens profile and glass types are all choices with upsides and downsides. I am sure this leads to optical consequences in terms of aberrations that need more controlling. So this complicates your design process. And if you want extra compactness then you will look to use smaller prisms, but then you start to eat into your field of view. Is FOV important to your concept or not? You need to balance out opposing requirements all the time, in achieving the optical specification you have and controlling undesirable effects. If you have cost targets (and who doesn't) you may have to think carefully about how thoroughly you blacken internal surfaces. Your priority to make the bins compact may give you fewer options where to put internal baffles.This is before you get to thinking about stuff like eyecups and focusing mechanisms. Anybody can make super smooth and backlash-free focusing and also luxurious feeling and precise eyecups, but hey all of a sudden you have added 75 grams or 3 ounces to the weight: damn!Tricky. And then when they have achieved what they think is a super fine balance of all the opposing requirements, someone on here grumbles that the last 5 % of the FOV isn't sharp enough......Lee</blockquote>

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