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Why small objectives on the new 1-8x scopes?

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Urimaginaryfrnd View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Urimaginaryfrnd Quote  Post ReplyReply Direct Link To This Post Posted: January/25/2012 at 11:47
The F stop discussion is history a F 1.4 opens wider than a F 1.8 allowing more light to enter striking the film quickly.  The variable factors are speed of film + F stop + aperture opening size.
FOR 100asa   bright daylight F16   1/250 sec is typical but todays digital does not hold to the same constraints as the limits of film, look at a digital video with night mode its like having night vision. 
 
 
Please realize that the military does not always know what they are doing Shockedoften decisions are made by a guy in an office who has no personal knowledge of the factors actually existing in the field.  I know a lot of dumb decisions that have come down simply because the guy making the decision has no subject matter knowledge but he has the rank and responsibility to decide and God forbid he would ask someone doing the job.

Edited by Urimaginaryfrnd - January/25/2012 at 14:13

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atp View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote atp Quote  Post ReplyReply Direct Link To This Post Posted: January/25/2012 at 11:50
Folks, read the answer dcjs gave above. If he is correct, then the reason we see only small 24mm objectives on these 1-8x scopes is because the manufactuer's can't build a 50mm objective for these scopes that actually works, and even going up to a 32mm objective would likely be very difficult.

I strongly suspect that dcjs's explanation (or something very similar to it) is basically correct, and that the optics engineers designing riflescopes know that. So for now let's assume that's the case...

Now go back and skim through all the just-so-stories people were making up to "explain" why all the true-1x variable scopes have small objectives. Those explanations are all completely wrong. This is a small lesson in how people don't like to admit, "I don't know why the world is that way", and sometimes don't even seem to notice that they don't know. Instead they make sh*t up.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote supertool73 Quote  Post ReplyReply Direct Link To This Post Posted: January/25/2012 at 11:54
Bite the hand that feeds you why don't you.  I would not bother asking any more questions if you are just going to sh*t on the people who try to help.  Loco
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SVT_Tactical Quote  Post ReplyReply Direct Link To This Post Posted: January/25/2012 at 12:04
Originally posted by supertool73 supertool73 wrote:

Bite the hand that feeds you why don't you.  I would not bother asking any more questions if you are just going to sh*t on the people who try to help.  Loco
Ditto
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Post Options Post Options   Thanks (0) Thanks(0)   Quote atp Quote  Post ReplyReply Direct Link To This Post Posted: January/25/2012 at 12:22
Aw, did I hurt your poor little feelings?

Higher standards lead to better understanding. You'd rather have low standards, and not point out when answers are confusing and make no sense?

Yes yes, many of the "explanations" offered in this thread are potentially legitimate reasons why somebody might decide that, on balance, for their purposes they'd rather go with a scope with a 24mm rather than a 32mm or 40mm objective. That's fine, and of course there's nothing wrong with bringing them up and discussing them in this thread.

But the facts appear to say that those points have nothing to do with why no one is offering a 1-8x40mm scope right now. If a manufacturer could build a 1-8x40mm scope for the same price and quality as the 1-8x24 scopes, it would definitely work better in some ways and it would sell. Furthermore, many of the "problems" suggested are very minor, and most people would completely ignore them and cease to even notice them as problems if you put an actual working 1-8x40mm scope in their hands. Apparently physics makes that 1-8x40mm scope too hard for anyone to build, at least right now. Most of other putative problems are just noise distracting us from that main point.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SVT_Tactical Quote  Post ReplyReply Direct Link To This Post Posted: January/25/2012 at 12:33
ATP, your walking a thin and fragile line, Check your fire.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote supertool73 Quote  Post ReplyReply Direct Link To This Post Posted: January/25/2012 at 12:44
You did not hurt anyone poor little feelings.  You are just being a jackass so I called you out on it.  There is just no need for it at all, people are just trying to help with what they know.  dcjs based upon his website listing is probably an optical designer so he knows stuff most people will not.  We all appreciate knowledge like that.  But that does not mean you need to be a dink about it.

If you keep being a jackass your time here will probably be short.  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote dcjs Quote  Post ReplyReply Direct Link To This Post Posted: January/25/2012 at 13:04
Originally posted by atp atp wrote:

I think you go that backwards. A "faster" lens (one that that gathers more light) is one with a higher numerical aperture, or a lower f-number. High NA (low f-number) lenses definitely do get very expensive.

Good catch. I always think of the larger NA as the "higher" f-number, although the numerical value of the number is actually lower.

This thread is another reminder why the internet is such a frustrating place. Everybody has an opinion and subsequently has to defend it vigorously because it is his opinion, and to the average reader, facts seem to compete with conjecture at eye level.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote BeltFed Quote  Post ReplyReply Direct Link To This Post Posted: January/25/2012 at 13:22
Now go back and skim through all the just-so-stories people were making up to "explain" why all the true-1x variable scopes have small objectives. Those explanations are all completely wrong. This is a small lesson in how people don't like to admit, "I don't know why the world is that way", and sometimes don't even seem to notice that they don't know. Instead they make sh*t up.
 
I concur with supertool. Most answers were qualified by the posters as to why, but not certain as to why, and each one had reasons why. No one said they were experts that gave you an answer, just their experience.
With your statement above, you have basically called us all ignorant liers. IF that was your original intent with this thread, then you Sir are a jerk, and I have no time for you.
The regulars here are fine people, and will help in any way they can, but you atp  are not worthy of that help, so pound sand.
Life's concerns should be about the 120lb pack your trying to get to the top of the mountain, and not the rock in your boot.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tahqua Quote  Post ReplyReply Direct Link To This Post Posted: January/25/2012 at 13:57
Originally posted by atp atp wrote:


Yes yes, many of the "explanations" offered in this thread are potentially legitimate reasons why somebody might decide that, on balance...........

But the facts appear to say that those points have nothing to do with why no one is offering a 1-8x40mm scope right now.  .
 
That is a contradiction. In fact the posters were trying to give their reasons. I found Ufrnds reasoning quite sound, in particular.
The responses given have plenty to do with your original post.


Edited by tahqua - January/25/2012 at 14:12
Doug
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Urimaginaryfrnd Quote  Post ReplyReply Direct Link To This Post Posted: January/25/2012 at 14:07
atp --- while you personally may want to own a 1-8x40 ---- The U.S. Military  -  CHOSE WHAT THEY WANTED.  If it doesnt work for you - they dont really care.  I have no desire to own a 1-8 x40, however I just bought a 2.5-10x56 Trijicon Accupoint for low light hunting of coyotes.  My needs for this optic were different than that of the U.S. Army.     Really its ok for them to buy what they want.  If you want to suggest someone build a 1-8x40 optic thats ok also.  When the SWFA SS 1-4x24 Tactical 30mm Riflescope  came out I mentioned that to me anyway a 1-6 would be preferable to a 1-4 and this year at shot show SWFA announced they will be building a SWFA SS HD 1-6x24 Illuminated FFP  so 24mm divided by 6x gives a 4mm exit eye pupil.  So at   3.4 power and below the scope will be just as bright as a 6x42 scope.   For CQB distances this is fine VS for hunting distances it may not be.  Remember this is the tactical forum not the HUNTING forum these are purpose driven builds - tough - reliable - heavy duty.
What you are looking for is one of the NEW Zeiss Conquest Duralyt 2-8x42, #6, $999.95


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Post Options Post Options   Thanks (0) Thanks(0)   Quote cheaptrick Quote  Post ReplyReply Direct Link To This Post Posted: January/25/2012 at 17:30
Originally posted by supertool73 supertool73 wrote:



If you keep being a jackass your time here will probably be short.  

VERY short, indeed.  
If at first you don't secede...try..try again.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote koshkin Quote  Post ReplyReply Direct Link To This Post Posted: January/28/2012 at 18:29
Interesting thread.  The truth, of course, combines several explanations that are already offered in this thread (and a couple of points that I do not see presented).  It is also interesting that the gist of the explanations went right over the original poster's head, which partially explains why he got his panties in wad over nothing.

Let's consider a few points.

First is the design intent.  Most high erector ratio scopes coming to the market now (i.e. the 1-8x and 1-10x scopes) are really designed to replace both red dot sights and 1-4x sights.  As such, they are often optimized for performance at lower magnification.  Performance at higher magnifications is an added feature, not the cornerstone of the design.  First and foremost, these scopes have to be optimized at lower magnifications and that is where they spend most of their time.  They are only used at higher magnifications occasionally.  Hence, the performance at higher magnifications has to be decent, but it is not the highest priority.

Second is the overall package.  There is no compelling reason why a larger objective can not be utilized with low magnification.  It is not straightforward if you want to keep the focal length of the objective lens short, but it can be done.  However, that opens a new can of worms.  Let's say I take a Leupold CQBSS and shove a 32mm objective lens onto it without changing anything else (beyond re-optimization of the objective lens group itself).  The immediate effect you will see (aside from a larger exit pupil at higher magnifications) is much shallower depth of field.  In fact the dept of focus of the objective lens group will become so shallow, that I will be forced to put a sidefocus knob onto the scope complicating both the design and the operation (this is for those of you who wonder why march 1-10x24 has side focus).  

In order to keep the depth of field the same, I would need to increase the focal length  of the objective lens system.  Aside from increasing size and weight, that changes the FOV, so to achieve the same FOV as the scope with a smaller objective lens I would have to rework the rest of the scope.  Since I would have to accomodate a much larger spot size at the first focal plane of the scope, the spot size at the second focal plane would go up correspondingly.  Hence, aside from a larger objective lens, I would also end up with a larger maintube and larger eyepiece.

If there is enough market out there for 20 inch long, four pound 1-8x50 scope, I am sure someone will make one soon enough.

As a practical matter, since I am in the middle of testing a 1-10x26 scope (and having just finished testing a 1-6x24), I can certify that the overall performance even at high magnifications is pretty well balanced and for the intended purpose of this scope I do not feel shortchanged by a 26mm objective.  It performs superbly at 10x during daylight when my eye pupils is pretty small and maintains perfectly adequate performance in low light as I lower the magnification to somewhere between 4x and 6x.

ILya
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Urimaginaryfrnd Quote  Post ReplyReply Direct Link To This Post Posted: January/28/2012 at 18:41
Thanks Ilya Excellent

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Post Options Post Options   Thanks (0) Thanks(0)   Quote gulf1263 Quote  Post ReplyReply Direct Link To This Post Posted: January/29/2012 at 15:38
Hi Iliya, see you survived SHOT.
Good points about the end user, US military defining the parameters of the optic.
As I tried to point out to atp, the USMC specified the parameters for the Leupold 1.1x8 optic.
Their original intent was to use it on the M 240B MMG, it was not designed for any other use at the time.
It's design parameters were mission driven, Leupold gave the end user what they wanted and could care less about what atp thought.
It is being used for other auxiliary missions now because it can meet those mission parameters.
The Leupold is a combat optic pure and simple.
Many years ago I spected out an optic for an agency and was told that the agency would need to buy several thousand at what at that time was for a very high price to pay off the R&D and production set up costs. The agency adopted another optic.
I suggested to atp that he try hunting optics for his hunting use.
Oh well.
I don't want to get into an online fight and jam up this forum, we all learn so much from each other.
Thanks to everyone who made a positive contribution to this discussion.
Art



Good day.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote atp Quote  Post ReplyReply Direct Link To This Post Posted: January/31/2012 at 22:47
Originally posted by koshkin koshkin wrote:

However, that opens a new can of worms. [...]

Interesting stuff, and exactly the sort of answer I was looking for. Thank you.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote lumberjack149 Quote  Post ReplyReply Direct Link To This Post Posted: February/01/2012 at 06:04
great read, thanks for the info Ilya.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote lumberjack149 Quote  Post ReplyReply Direct Link To This Post Posted: February/01/2012 at 06:11
maybe i had too much coffee this morning but this would have been my response if you asked me to respond to ATP original question...
Joe's Dad: [sarcastically] Hey! How exactly is a rainbow made? How exactly does a sun set? How exactly does a posi-trac rear-end on a Plymouth work? It just does.
[guffaws]
Joe's Mom: It just does.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote stickbow46 Quote  Post ReplyReply Direct Link To This Post Posted: February/02/2012 at 14:09
Lots of great info thrown out there,I understood most but not all & that's why I keep comming back so that one day I might be a better shooter...Thanks guys Excellent
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