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Old Wednesday 24th April 2019, 20:58   #19
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Join Date: Jul 2005
Location: Twin Falls, Idaho
Posts: 2,276
Originally Posted by typo View Post
Brightness is a perception, not a measure of light levels. You might say it's a figment of your imagination, but in reality it's often in response to a difference in some physical parameter or another. It might be some small difference in spectrum, contrast, resolution or glare is enough makes a perceptual difference, but It is also in the nature of psychology that if you expect the x42 to be brigher, it may well appear to be.

That David seems always to be around with all that ... LOGIC CRAP. Too many people see a binocular as aperture, magnification, and possibly coatings. In the REAL world, there is a bit more to consider leading to real or imagined image brightness:

1. Smoothness of optical surfaces
2. Precision in design (caring or understanding)
3. Best choice in selecting glass types, curvatures, and spacings
4. Precision in manufacturing
5. Precision in testing
6. Primary and secondary baffling
7. Edge blackening (a lost art)
8. Slotted prisms (in Porros)
9. Size and position of the field stop
10. Knife edge on that stop
11. Number of elements in the eyepiece
12. Type of eyepiece
13. More

14. Personal physiology and PERCEPTION

In most cases, #14 will supersede the previous 13

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