I've had the Carl Zeiss 4x12 monocular for almost ten years. If you visit museums frequently, I strongly recommend this unit for two reasons:
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br /(a) The view is wide, clear, undistorted, and adds no color. You don't see the lens! You only feel closer to the object, which is exactly what you want. (Don't be tempted by cheaper optics -- you get what you pay for.)
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br /(b) 4x is just the right amount of magnification power. 4x means you see the object as if you were at 1/4 the distance. But more importantly, this unit allows you to approach the object as close as 30 cm or 12 inches. If you are right up to the glass display case with that jeweled artifact inside, you can see it as if it were in your hand. (If you suffer from back pain, you can view low objects without bending your back.)
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br /Are there shortcomings? Yes. I hope the following minor issues will be resolved in the next generation:
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br /(a) The neck strap is fixated to the unit (i.e., cannot be detached). It is too long for me; I prefer to keep my monocular in my pocket. But I can't bring myself to cut the neck strap. (Perhaps I should.)
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br /(b) The rubber eye cup (the flexible piece that folds over the eyepiece) cannot be replaced. I suspect this is the weak point of this unit. Although mine hasn't failed yet, it is likely to break first.
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br /(c) The focusing mechanism is a simple push-pull tube that extends the objective lens in or out from the lens barrel. A minor improvement would be a screwed, twisting mechanism that allows finer adjustment, and would tend to hold focus position.
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br /Hope this helps!
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