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Posted: 9/11/2006 9:21:40 AM EDT
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I am comparing the IOR 2.5x-10x42 tactical scope with Leupold's 3.5x10x40 Mark 4 scope. I like the Leupold better but the IOR is cheaper. Leupold 3.5x-10x40 LR/T IOR 2.5x-10x42 Tactical I am concerned however with the fact that the IOR does not have adjustable parallax. Does anyone know how a manufacturer determines when a scope needs adjustable parallax? Is it simply a price point? Do I really need adjustable parallax with a 2.5x-10x optic? I plan to engage targets out to 600 meters. Any opinions would be appreciated. Thank you |
Because an objective (the big lens at the front) can only focus objects at a single distance precisely on the reticule, a scope can only be paralax free at exactly one distance* at a time. Scopes without paralax adjustments are set at the factory to be paralax free at some given distance {typically 100 yards/meters for smaller scopes, and 300 meters for scopes with more long range asperations}. Since a rifle scope has two focal planes, it needs two focusing mechanisms. The eyepiece focusing adjustment focuses the light eminating from the reticule plane of the scope for your eye, while the paralax adjustment focuses the objective image on the reticule. If you need to be paralax free at 100 yeards/metres and at 600 yeard/metres, then you will likely desire paralax adjustment. Some people can learn to shoot around the lack of paralax adjustment by using the (small) exit pupil of the scope to center their eye on the optical axis. there is some depth of field to the distance that is precisely focused on the reticule (say dozens of yards/meters). A note on the Leupold scope:: There are two 'kinds' of 3.5-10*40 scopes, front focal plane (58850 non-illuminated mil-dot M1 dials) and second focal plane (52128 non-illuminated mil-dot M1 dials) . The front focal plane allows using the mil dots as range finders at any magnification, while the second focal plane only uses the mil-dots as range finders at one set magnification. With a little looking around (Google on the Leupold model number), you can find the SFP scopes in the $870 range and the FFP scopes in the $950 range. There are 3 kinds of 'dials':: 1/4 MOA M1 dials; 1/2 MOA M2 dials; and 1 MOA range w/ BDC 1/2 MOA windage M3 dials. |
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MitchAlsup, that's a great answer! glock24, manufacturers have a number of concerns, most of them having to do with selling product. Maybe all the concerns have to do with selling product. Most of what you see in the market place is customer driven. Customers say they want a feature, and manufacturers do try to get them it. So, if we go with the above as an assumption, we can say that any feature is put into the "package" for one of two reasons or both reasons: the feature will help sell more units; the feature makes a much better product in that the function is very necessary. Leaving behind the reason that a feature will help sell more units, an adjustable objective is about reducing parallax error by being able to find critical focus at any specified distance within the design parameters of the instrument, sorry, scope. Using Air gun shooting as an example, you'll need certain features beside your skills to help make every shot as consistent as possible. One such feature is the need for a small exit pupil that will force you to place your eye as close as possible, if not right in there, to center axis of the scope's lens system. The reason is the further away from the center axis, the more likely you will induce parallax error. With a small exit pupil, you can't see through the scope if your eye isn't correctly placed. An adjustable objective is another feature you'll need to help reduce parallax error. You have a low weight projectile moving at a low velocity and gravity is a bitch. All errors are accumulative. The more error you can remove, the better to make consistent shots, and consistency is accuracy. How do this relate to center-fire rifles? From the mechanics of shooting, sight alignment, trigger and breath control, etc. are the same. But how necessary is an adjustable objective with its ability to reduce parallax error at any specified distance? It all depends. Anecdotally (not sure if that's a word), Marine snipers using Unertl's 10X were very good at consistently hitting their targets at unknown distances from 300 yards to 1000 yards. How much more would an adjustable objective have helped them? beats me. I've always thought that a lot of people look at parallax error as the ultimate boogey man. Under certain conditions it certainly is. It affects iron sight shooters as much as telescopic sight users. Any time light travels through a medium, you'll have parallax error, and Air is a medium. That's a fact of life. We'll never get rid of the error. We can only correct/compensate for it. We learn to shoot with it there, always lurking in the background. We won't have to worry coming home one night to find empty bottles of our beer in front of the TV with UFC on and finding our woman sleeping underneath the kitchen table table wearing nothing but her panties on her head and a satiated smile on her face. Parallax error won't do that to us. Don't let her tell you otherwise.  Both scopes you picked are very good instruments. You'd be happy with either in my opinion, but you'll need to be the judge of it. We all shoot differently. Shooting is one of the ultimate Zen experiences. You got to know your self to be good at it. |
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Parallax is there in a 10x but for the most part it is not a big deal. I use an IOR 2.5-10x myself w/ the Dragonov reticle and I really like. In some 10x scopes it is more important to have a parallax in them. The MK4 10x scopes really need it for the focus. I prefer the Leupold MK 4 scope I use 3 MK4 fixed and 2 of the variables MK4. Here is one of the MK4 10x  Here is a MK4 2.5-8x36mm  Here is a 6.5-20x50mm  Here are two USO ST10 I use and they do not have a Parallax adjustment. USO CSGW-ST10: I shot this one out to 1000yds and Parallax is not a problem for me.  USO Super Slim-Line ST10: This one is for sale it is the fist ever Slim-Line ST10 it was just made a few months ago and is an outstanding scope.  Whatever scope you are looking for we can help you with! Mike @ CSGW www.csgunworks.com [email protected] Here’s some testimonials about CS GunWorks What do YOU have to say about CS GunWorks What Do You Think Of Cs Gunworks? FEEDBACK about CSGUNWORKS.com |
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I've been looking at Valdada's for a while. It appears that they have a new 2.5-10 with side focus and FFP! It isn't shown on Valdada's outdated website. Mike, can you confirm? Green Mountain SWFA |
That's not a side focus, it is the illumination rheostat. |
You may want to follow this thread; It's a future group buy over on Snipershide.com involving a 3-18x42mm FFP IOR www.snipershide.com/ubb/ultimatebb.php?ubb=get_topic;f=19;t=004544;p=1 |
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