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Joined: Dec 2008
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Campfire Oracle
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Campfire Oracle
Joined: Dec 2008
Posts: 78,300 Likes: 1 |
JB...correct me if Im wrong but the 6x36 should have an exit pupil of 6mm...a tad more light transmission than 40+ year old eyes are even capable of using. Should be bright enough without going to the 6x42....
Last edited by ingwe; 08/02/16.
"...the left considers you vermin, and they'll kill you given the chance..." Bristoe
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Joined: Jul 2001
Posts: 60,156 Likes: 13
Campfire Kahuna
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Campfire Kahuna
Joined: Jul 2001
Posts: 60,156 Likes: 13 |
Yep, a lot of us lose some pupil expansion as we get older, so the 7mm exit pupil on the 6x42 doesn't help as much.
However, larger objective lenses do provide a sharper image, regardless of our own pupil's size, though the difference between 36mm and 42mm isn't vast. This optical principle is most noticeable in binoculars, especially 10 powers.
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.”
John Steinbeck
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Joined: Jun 2006
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Campfire 'Bwana
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Campfire 'Bwana
Joined: Jun 2006
Posts: 46,103 Likes: 6 |
Yep, a lot of us lose some pupil expansion as we get older.... Well, I don't know about you guys, but that's why I read the .223 AI thread---to work on my pupil expansion, and keep it where it needs to be.
A wise man is frequently humbled.
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Joined: Mar 2004
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Campfire Tracker
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Campfire Tracker
Joined: Mar 2004
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Interesting the comment about 10x binoculars, John. Can you expand on that a little?
Defend the Constitution
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Joined: Jul 2001
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Campfire Kahuna
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Campfire Kahuna
Joined: Jul 2001
Posts: 60,156 Likes: 13 |
Because of the high magnification for hand-held binoculars, smaller objective lenses are more detrimental to the sharpness of the view in 10x than 8x binoculars.
The reason smaller lenses reduce sharpness is there's more lens edge for the total lens area, and lens edges scatter light. This cuts down perceived detail, partly through reduced contrast. More magnification exaggerates this effect, because it also shrinks the exit pupil, which also reduces contrast.
Years ago I guided for an outfitter in central Montana for a couple of years. This was when I was doing the optics column for Petersen's Hunting, so I had several binoculars to test, while we did some pre-season scouting, among them a Simmons 10x50 porro prism that as I recall retailed for $50. The outfitter wasn't much of a glasser--like many guys who grew up hunting in eastern Montana, he preferred driving closer.
But one of his previous year's clients had given him, as a tip, a 10x20 Zeiss pocket binocular. He was extremely proud of it, but that didn't last long after I showed up, and the 10x50 Simmons not only provided a much brighter but sharper view.
In my experience, any 10x binocular with an objective size less than about 40mm suffers from this effect, even the very best. I haven't ever looked through a 10x30 or 10x32 that provided as much detail as the same company's 8x30 or 8x32, even when rested very steadily, and perceived detail is why we use binoculars. I do prefer 10x over 8x for open country, and sometimes even in woods, but all my 10x binoculars have at least 40mm objectives, and one has 50mm's.
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.”
John Steinbeck
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Joined: Mar 2004
Posts: 6,065
Campfire Tracker
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Campfire Tracker
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Defend the Constitution
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Campfire Regular
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Campfire Regular
Joined: Apr 2012
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I recently looked through a Swarovski and was amazed by how bright it was. It was almost like having a flashlight in your face, that was at 100 yards. You can still see the target.
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Joined: Feb 2010
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Campfire Ranger
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Campfire Ranger
Joined: Feb 2010
Posts: 15,718 Likes: 1 |
Because of the high magnification for hand-held binoculars, smaller objective lenses are more detrimental to the sharpness of the view in 10x than 8x binoculars.
The reason smaller lenses reduce sharpness is there's more lens edge for the total lens area, and lens edges scatter light. This cuts down perceived detail, partly through reduced contrast. More magnification exaggerates this effect, because it also shrinks the exit pupil, which also reduces contrast.
Years ago I guided for an outfitter in central Montana for a couple of years. This was when I was doing the optics column for Petersen's Hunting, so I had several binoculars to test, while we did some pre-season scouting, among them a Simmons 10x50 porro prism that as I recall retailed for $50. The outfitter wasn't much of a glasser--like many guys who grew up hunting in eastern Montana, he preferred driving closer.
But one of his previous year's clients had given him, as a tip, a 10x20 Zeiss pocket binocular. He was extremely proud of it, but that didn't last long after I showed up, and the 10x50 Simmons not only provided a much brighter but sharper view.
In my experience, any 10x binocular with an objective size less than about 40mm suffers from this effect, even the very best. I haven't ever looked through a 10x30 or 10x32 that provided as much detail as the same company's 8x30 or 8x32, even when rested very steadily, and perceived detail is why we use binoculars. I do prefer 10x over 8x for open country, and sometimes even in woods, but all my 10x binoculars have at least 40mm objectives, and one has 50mm's. Dang, you're smart about all this stuff, JB! 
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