Discovering Parallax

Discussion in 'Hunter (HFT) & Field Target (FT)' started by Lol Moore, Sep 11, 2013.

  1. Lol Moore

    Lol Moore Banned

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    Now after reading some recent stuff on here its very obvious there are some seriously knowledgable people when it comes to optics, so be gentle with me as I am learning.

    these are more observations rather than statements of fact or questions, and the terminoligy will make the experts cringe - but I know what I am trying to say :)

    Parallax.......I have had a lot of different scopes over the years from £50 Rhinos to several Leupolds and a £2000 March.

    I have always followed the general instructions re adjusting the eyepiece, we have all read them the purpose seems to be to get the reticle in focus for the user they generally follow the ines of the scope set to infinity looking at the sky adjust until its sharp.

    A while back i found this explaination and my attention was grabbed, it was more sensible to me:

    http://ateam.alotspace.com/ateamh/A_Team_Parallax_adj.htm

    This is more about getting the scope picture focus and the reticle focus "in the same place" as it were, following it did make a difference, it is as if the general description puts the reticle somewhere near the right spot in the in focus range, this method puts it in the middle - with me?

    One major observation I did make when I first got the March scope (2.5-25 x 42) was that it had an increbidle edge to edge clarity and depth of field, but if the focus was adjusted within a particular depth of field there was only one very precise spot where the "head bop" would reveal no aparent movement of the reticle in relation to the sight picture, it is almost as if there is a spot within the in focus range where the scope is truly parallax free

    Not sure what this means, also not sure if its an advantage or a disadvantage, not noticed it anywhere near as much with any other scope I have had.

    Anyway its been playing on my mind for a while and i just had to vent it while Big Bro is on :mad:
     
  2. Jon

    Jon Member

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    The idea of the focus is to eliminate the pa error, so why use it just set any where.

    In saying that had many scopes that were in focus and eye bell ret focused but still had severe pa error!
    Of all the PR Leups ever had and used, focus could be set any where and no pa error!
    Of the 7 attempts at getting a useable 80 they all had pa error which really showed up locked in a vice. Different model the 10-60 even on lowest 10 mag totally out of focus, pa eror is absolutely minimal. Deon ship them out set at 0D, to most that means having to wind eye bell ret focus in approx. 1 3/4 revs, also come optically centred.

    True altering eye bell focus will affect the range markings. when I set mine up in a hurry I didn't bother just marked the wheel. Later got fed up having no ret on low mag so adjusted eye bell and cant be arsed to redo the ranges 2 1/2 years on. It s coming off any way a T50 is going on next month while I have the March ret changed and put back to standard spec.
     
  3. Lol Moore

    Lol Moore Banned

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    Fascinating

    Jon, Jon, Jon...... I am still a novice remember, not so many acronyms please :eek:

    What is a PR Leupold (have to agree the two Leupolds I have seem to suffer very little from PA error)

    I assume by an "80" you mean a March 8-80x56 scope? are you then saying the March 10-60x52 does not suffer the same PA errors and that it would be most apparent at lowest mag slightly out of focus?

    Have you tried 7 March scopes and not got a good one :eek: if so where are these 7 scopes - in the bin I hope :eek: I would really like to have a March on my FT rig but this is worrying

    By "0D" i assume you mean Diopter?

    When you set yours up in a hurry - which scope are you refering to here?

    I was messing with the Nikko in the garden last night and its remarkable how much the eyepiece changes things, from all the way in to all the way out its looks equivalent to increasing the magnification by about x10 :eek: also the reticle is to my eye in focus over most of the eypiece travel :eek:

    When i mentioned setting within the in focus window what i mean is if say the sight picture is in focus with the side wheel being rotated over say 2 metres (the extremes being coming down or up to the focus point) I am winding down (clockwise from wheel side) to focus and have found i can set the eyepice to give little PA error at the top or bottom of the in focus range, if you follow the basic setting intructions (point at sky etc.) it can be anywhere in the in focus range - am i making any sense here :confused:

    have to say the Nikko I have is ranging very accurately on 40x, i like just ranging stuff around the garden and then checking with the laser, its very cool, and sad i suppose :eek:

    Its all very fascinating :eek:o
     
  4. Jon

    Jon Member

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    Most scopes 20mag ish the last 20 odd years will range to 45 yards fairly accurate.

    PR short for Premier Ret did power boosts and ret changes to production Leupolds up to June 2005.
     

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