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locking vs non locking focus?

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Kickboxer View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Kickboxer Quote  Post ReplyReply Direct Link To This Post Posted: August/24/2008 at 20:29
Originally posted by tahqua tahqua wrote:


Originally posted by 30mikemike 30mikemike wrote:

Update: called S&B and they said rare but possible. Send it back and they will analyze and fix for free if necessary. To put an NC in the same room with an S&B is like saying a Pinto and GT40 are both cars!
Aren't they?I don't think KB was putting his NC "in the same room" as S&B. He was just stating that he has seen this issue with his scope. Everyone here knows the Schmidt & Bender is an outstanding scope. Most also know what an NC is. Doug

Doug, quite true. I have found nothing to recommend an NcStar to anyone, while I have found nothing which would not recommend S&B.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 30mikemike Quote  Post ReplyReply Direct Link To This Post Posted: August/24/2008 at 20:36
Yup and Rosie and the playmate of the month are both women too. I know who I would in my hot tub (hint there would still be water in it and it would not smell like a dead carp!)
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Kickboxer Quote  Post ReplyReply Direct Link To This Post Posted: August/24/2008 at 22:09
Well, this is a battle you can't win because I have HAD the playmate of the month in my hottub... on MANY occasions. Use an analogy that makes some sense.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote crispycritter Quote  Post ReplyReply Direct Link To This Post Posted: August/24/2008 at 23:59
Originally posted by Kickboxer Kickboxer wrote:

Well, this is a battle you can't win because I have HAD the playmate of the month in my hottub... on MANY occasions.

 
 
 
 
Do tell, how did you keep the magazine from falling apart?Big%20Grin
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Kickboxer Quote  Post ReplyReply Direct Link To This Post Posted: August/25/2008 at 06:40
Originally posted by crispycritter crispycritter wrote:

Originally posted by Kickboxer Kickboxer wrote:

Well, this is a battle you can't win because I have HAD the playmate of the month in my hottub... on MANY occasions.

 
 
 
 
Do tell, how did you keep the magazine from falling apart?Big%20Grin
 
Endeavor to persevere...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Gunshow75 Quote  Post ReplyReply Direct Link To This Post Posted: August/25/2008 at 07:23
Originally posted by Kickboxer Kickboxer wrote:

Just because one scope is much cheaper than another does not mean that it cannot compare in MANY respects to another, more expensive, more capable piece of equipment. This carries true in all aspects of the Test and Evaluation world.

KB, your point is well taken. By definition, compare means to examine to find similarities and differences. Light will obey the laws of optics, whether in a toy or a tool, which is your point as I see it.


Tom



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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jon A Quote  Post ReplyReply Direct Link To This Post Posted: August/25/2008 at 13:24
If the toy is SFP and the tool is FFP, comparisons on reticle movement might not be valid.   While I don't think it should happen on any decent SFP, I can see it as "being more possible" than a FFP.  That was the point. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Gunshow75 Quote  Post ReplyReply Direct Link To This Post Posted: August/25/2008 at 14:32
Originally posted by Jon A Jon A wrote:

... I don't think it should happen on any decent SFP .. 

I am only trying to find an explanation for what is happening; nothing more.

There are several members on the forum who dislike equations, but I am going to use one to share my thoughts. The Thin Lens equation relates the focal length of a lens to the distance an object is away from the lens and the distance the image of that object will occur from the lens. I will provide numbers so you can check the math.

The Thin Lens equation is: 1/f = 1/O + 1/I, where f is the focal length of the lens, O is the distance of the object from the lens, and I is the distance from the lens that the image of the object is formed.

Assume that our imaginary objective lens is a simple thin lens that has a focal lenght of 100 mm. An object that is 1000 yards away will have it's image formed at 100.011 mm behind the lens. An object 500 yards away will have it's image formed 100.022 mm behind the lens. At 200 yards, the image forms at 100.055 mm, and at 100 yards, the image forms at 100.109 mm. An object 50 yards away forms an image at 100.219 mm behind the lens.

These displacements are propogated through the scope, and if the scope is a variable power having 3X gain, the displacements will become 3 times larger at the highest power.

When the scope is set at the factory to be parallax free at 100 yards, the reticle is positioned to be coincident with the virtual image of the object that was 100 yards from the scope. We use the ocular lens to focus on the virtual image. For objects at any other distance, the virtual image of the object will be in focus at it's displaced distance in front of or behind the reticle. Toy or tool, the process is the same.

I think that "jiggling the eyepiece" and holding one's eye stationary is the same as holding the eyepiece stationary and moving your eye. Both cause the same effect.


Tom



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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jon A Quote  Post ReplyReply Direct Link To This Post Posted: August/25/2008 at 17:05

Oh, now I see what you’re getting at.   Introducing parallax error when the parallax is not adjusted correctly.  That could be, I never checked that.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Kickboxer Quote  Post ReplyReply Direct Link To This Post Posted: August/26/2008 at 18:11
Originally posted by Gunshow75 Gunshow75 wrote:

Originally posted by Kickboxer Kickboxer wrote:

Just because one scope is much cheaper than another does not mean that it cannot compare in MANY respects to another, more expensive, more capable piece of equipment. This carries true in all aspects of the Test and Evaluation world.

KB, your point is well taken. By definition, compare means to examine to find similarities and differences. Light will obey the laws of optics, whether in a toy or a tool, which is your point as I see it.

You got it, Gunshow. You read me well.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote brodeur272 Quote  Post ReplyReply Direct Link To This Post Posted: August/27/2008 at 11:00
Hhaven't had that type of problem that I can see.  But after having the eyepiece adjustable focus rings, I haven't gone back to the Leupold/older Nikon style.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ed Connelly Quote  Post ReplyReply Direct Link To This Post Posted: August/27/2008 at 21:30

                                    

 
                                                                                  Bandito


Edited by Ed Connelly - August/30/2008 at 12:35
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