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brightnes of angled vs straight

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webrehm View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote webrehm Quote  Post ReplyReply Direct Link To This Post Topic: brightnes of angled vs straight
    Posted: January/21/2012 at 21:29

Is a straight spotting scope going to be brighter due to the lack of a prism to bend the light at 45 degrees?

tks

Dennis


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Klamath View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Klamath Quote  Post ReplyReply Direct Link To This Post Posted: January/21/2012 at 23:54
In theory yes.  However in practice, not really. There IS another glass surface to pass light through.  Modern glass and coatings can pass upwards of 99.5% of light per surface, so this amounts to a  fraction of a percent.   I don't think the average eye will be able to tell if the light transmission drops from, say 90% to 89.5%.  Some things are too insignificant to worry much about.  If you prefer a straight spotter, go for it.  If you prefer an angled spotter, go for it.  If your buddy gives you grief about how his straight will be brighter than your angled, just ignore him.  What can be seen on a optical test bench does not necessarily transfer into practical field observational differences. 

Edited by Klamath - January/22/2012 at 00:00
Steve
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RifleDude View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote RifleDude Quote  Post ReplyReply Direct Link To This Post Posted: January/22/2012 at 21:19
Usually, straight scopes have a prism system with just as many reflective surfaces as an angled scope, because the upside down image arriving at the prisms have to be inverted right side up to the eyepiece.  They differ only in geometry.

There's no light transmission difference whatsoever between an angled and straight scope of the same brand & series, assuming the scope in question is of decent quality.
Ted


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Bitterroot Bulls View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bitterroot Bulls Quote  Post ReplyReply Direct Link To This Post Posted: January/22/2012 at 23:07
Aren't you both right?
 
Don't roof prism spotters (Zeiss) need an extra surface for angled, while porros (Kowa) don't?
 
Either way, I doubt any person could see a difference.
-Matt
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Klamath View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Klamath Quote  Post ReplyReply Direct Link To This Post Posted: January/24/2012 at 13:42
OK, not to seem to be ignoring this thread, but my research is so far unverified.  It has always been my understanding that there is an extra lens or prism involved with the image path on a straight vs angled spotter, with the angled one having the extra surface.
 
It is also my understanding that Ted is also right to a degree as changing the light path geometry is possible with a prism position change.  It has been my understanding that this is maybe not so simple as a  flip of the prism mount, but if done will still require another glass surface somewhere.
 
I just got off the phone with Vortex and the guys I talked to said they "thought" there was another surface in the angled.
 
I have a couple of other questions waiting answers out there and am just waiting.  This question is sort of like a little mosquito buzzing around just behind your ear.  Big Smile
 
So anyway, when I know, I'll either admit the error or ...  It seems you can learn something any time you hit the submit post button.
 
Probaly should PM Ilya
Steve
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Bitterroot Bulls View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bitterroot Bulls Quote  Post ReplyReply Direct Link To This Post Posted: January/24/2012 at 14:04
Sounds like a good question for Henry over on BF, Steve.
-Matt
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Dyelynn View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dyelynn Quote  Post ReplyReply Direct Link To This Post Posted: January/24/2012 at 17:44
Originally posted by RifleDude RifleDude wrote:

Usually, straight scopes have a prism system with just as many reflective surfaces as an angled scope, because the upside down image arriving at the prisms have to be inverted right side up to the eyepiece.  They differ only in geometry.

There's no light transmission difference whatsoever between an angled and straight scope of the same brand & series, assuming the scope in question is of decent quality.


a straight scope or spotter would have a single prism to flip the image, but the light still travels on a straight path... an angled scope or spotter or binos for that matter would need an extra reflective surface to redirect the light for every bend in the body.  at least that's what my pickled brain comes up with when considering the construction of optics.

however, mirrors not only reflect light, but are able to amplify it, so i don't think an angled spotter would inherently be any less bright than a straight one... on the contrary, it seems to me that they might well have the possibility of being brighter, given the same glass.

i'm just spit-balling of course :)
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muleycrazy View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote muleycrazy Quote  Post ReplyReply Direct Link To This Post Posted: May/27/2012 at 14:20
I cant see a diffrence in them
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