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10X42 vs 10X50 |
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RStoddard11
Optics GrassHopper Joined: September/08/2018 Location: New York Status: Offline Points: 3 |
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I know this is an old thread, but being from the photography world I will offer the followinf that was briefly touched on.
while exit pupil matching pupil size does allow the same amount of light, having a pupil smaller than the exit pupil is the same as stopping down or restricting the pupil size vs total available. You may have a 5mm area of light but taking that 4mm center area into your eye increases contrast, makes the plane of focus larger and increases the size of the center sweet spot so for a tripod mounted 10x50, perhaps more of the image is in focus and looks better than the 10x42 if stationary and you look around the image. I think this is even more important than the low light argument for 10x50 vs 10x42. |
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RStoddard11
Optics GrassHopper Joined: September/08/2018 Location: New York Status: Offline Points: 3 |
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http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/stop.html
f number and exit pupil |
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RStoddard11
Optics GrassHopper Joined: September/08/2018 Location: New York Status: Offline Points: 3 |
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https://www.cloudynights.com/documents/binoexit.pdf
This is an even better document, quite long winded, but basically explains (in lower light) that having a pupil slightly smaller than the exit pupil will significantly increase brightness and focus/clarity. In bright daylight, it may not matter. |
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oldfortyfive
Optics Apprentice Joined: June/16/2015 Status: Offline Points: 76 |
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Reality is ugly for most people. As usual you speak the ugly truth. I have a wide variety of binos because I like binos. I could grab any one of them at any time and not be unhappy. Price has nothing to do with it. |
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Kickboxer
MODERATOR Moderator Joined: February/13/2008 Status: Offline Points: 23679 |
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I can't measure it... don't have an optics lab available... but, there are some companies I view as trustworthy. Light transmission numbers to me are indicators, but not deciding factors. I have two binoculars that claim to have the same transmission numbers... I don't know if the better one is lying... but I do know the other is...
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Opinion,untempered by fact,is ignorance.
There are some who do not fear death... for they are more afraid of not really living |
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koshkin
MODERATOR Dark Lord of Optics Joined: June/15/2004 Location: United States Status: Offline Points: 13181 |
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I can measure it and do have a lab available. And it doesn't matter. For any remotely decent modern design, the actual light transmission is close enough to be not critical. ILya
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Kickboxer
MODERATOR Moderator Joined: February/13/2008 Status: Offline Points: 23679 |
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I believe that was my point...
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Opinion,untempered by fact,is ignorance.
There are some who do not fear death... for they are more afraid of not really living |
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