Rifle Scopes  New Kahles 5-25 Variant

Dthomas3523

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  • Jan 31, 2018
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    I think the changes (hate to call them upgrades) are fairly decent.

    If they want a premium price above what they already charge.....ehhhh.
     
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    Secant

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    So its a K525i with throw lever & parallax spinner? All the specs match the K525i exactly. Am I missing something?

    Edit: not all the specs match - I'm a dummy.
     
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    Secant

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    Gotcha. I missed the FoV
    DLR FoV: 7.7m - 1.6m.
    K525i FoV: 7.1m - 1.5m

    Also missed the different turrets, lol. I like those 10mil/rev turrets over the 16mil/rev on my k525i. I've been using the K525i as a crossover optic (range time in summer and hunting in fall), and my biggest complaint is the 16mil/rev turrets. Hmmmmm, I wonder what Kahles would charge to swap turrets??
     

    VargmatII

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    I'm pissed they won't put the msr2 in the 318i but they are putting it in the 5-25 wtf
    I dont know, if I could pick and choose, I would have something like a MSR 1.5 with most feautures from the MSR 2 but not all.
    Im not sure why I would need the 1 mil square hashes around the center and also the 4 and 5 MIL hashes in the fine measure seems pointless to me, I know, I know, small details, but anyways.

    I ran the regular MSR in a Schmidt 5-25x for two years and it was great.

    It is a bit strange that they dont offer the MSR 2 in the 3-18x. Wonder why?
     

    littlepod

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    I am digging the 10 mils per rev. I like that spacing more than the 15mils per rev on the ZCO. I'll keep an eye out on what the street price is going to be.
     

    rydah

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    I wonder if the strange reducer ring thing going on in the eye piece is gone. Take that away and I’ll grab the newer version, extra FOV is always nice but that’s my biggest gripe with the 525i.

    The other touches are nice too but keen to hear what peoples experiences with it are and the eye piece/image.
     

    Dthomas3523

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    Also when comparing FoV with the ZCO, it looks like ZCO 527, has a 7m/100m FoV, and Kahles at 5x has 7.7m/100m. That's 10% more FoV.

    Yea, but 10% of what.

    What are you going to do with say 2 extra feet @ 100 (and that’s on 5x). Zco @ 12x would be about 82’ @ 1k yds. 10% more is like 90’.


    On 27x the Zco is about the same as the Kahles at 25x @ 100yds.

    My stuff is just napkin math, but the point is, make sure that 10% means something. 10% of small number = small change = won’t matter practically.
     

    darth_ritis

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    My one complaint with my K525i is the 16 mil per rev turrets. My eyes would really appreciate 10 mil per rev. I know I would lose a ton of cash swapping but dammit, what's my elevation at? Very tempting.
     

    Glassaholic

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    If I did my calculations correct the new FOV is 23.1’ at 100 yards which is a definite improvement over the previous K525i which was 21.3’. Kahles had great turrets before at 16 mil per turn but at 10 mil per turn may be downright amazing. This seems to be an update that could put the K525i back in the running with other competing models. Some reports of the K525i indicated that resolution above 20x fell off somewhat so it will be interesting if they have fixed that issue as well.
     
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    littlepod

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    I have no clue how FoV works in terms of how it scales per magnification, but if it's a linear scale then -

    MagnificationZCO (FoV)Kahles (FoV)% difference
    577.710.00%
    66.757.3959.56%
    76.57.099.08%
    86.256.7858.56%
    966.488.00%
    105.756.1757.39%
    115.55.876.73%
    125.255.5656.00%
    1355.265.20%
    144.754.9554.32%
    154.54.653.33%
    164.254.3452.24%
    1744.041.00%
    183.753.735-0.40%
    193.53.43-2.00%
    203.253.125-3.85%
    2132.82-6.00%
    222.752.515-8.55%
    232.52.21-11.60%
    242.251.905-15.33%
    2521.6-20.00%
    261.75
    271.5
     

    Stoweit

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    Anyone heard a street price yet? I wonder if the extra long throw lever can be removed, I never had a problem turning it before. Turrets look great.
     

    Secant

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    My understanding is that FoV is not exactly linear, but it comes close to scaling linearly near the top end (maybe @koshkin can jump in to clarify). Also, when comparing the FoV on the same magnification as a percentage, I think looking at the area might be a little better metric than at the relative linear measurements. We view the image 2-dimensionally not 1-dimensionally, and the area is a function of the squared linear measurement (pi times radius squared).

    For me, I tend to just look at the difference in magnification to achieve the same/similar FoV as opposed to look at the difference in FoV as it provides a more practical approach (again, just for me). If one optic needs to be on 14.7x to achieve the same FOV as a second optic on 15.3x, I really won't notice the difference in application. However, if I look and see that optic B has 10% more linear FoV than optic A on a given magnification, I might put too much weight in choosing optic B when the difference won't matter in application.

    On the low end, I believe the Original Kahles k525 will have the same FoV as the ZCO when the Kahles magnification is about 0.5x lower than the ZCO. In the mid-range, the Kahles needs to be about 1x lower than the ZCO, and on the high end the Kahles needs to be about 2x lower than the ZCO.

    1610734357891.png
     
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    TacticalPlinker

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    Does anyone here have any experience with Kahles parallax spinner that they show in the picture? That appears to be an add-on (from their catalog) that you just have held in place with a set screw.
    Once you attach it does it scratch the crap out of what's underneath?
     

    littlepod

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    My understanding is that FoV is not exactly linear, but it comes close to scaling linearly near the top end (maybe @koshkin can jump in to clarify). Also, when comparing the FoV on the same magnification as a percentage, I think looking at the area might be a little better metric than at the relative linear measurements. We view the image 2-dimensionally not 1-dimensionally, and the area is a function of the squared linear measurement (pi times radius squared).

    For me, I tend to just look at the difference in magnification to achieve the same/similar FoV as opposed to look at the difference in FoV as it provides a more practical approach (again, just for me). If one optic needs to be on 14.7x to achieve the same FOV as a second optic on 15.3x, I really won't notice the difference in application. However, if I look and see that optic B has 10% more linear FoV than optic A on a given magnification, I might put too much weight in choosing optic B when the difference won't matter in application.

    On the low end, I believe the Original Kahles k525 will have the same FoV as the ZCO when the Kahles magnification is about 0.5x lower than the ZCO. In the mid-range, the Kahles needs to be about 1x lower than the ZCO, and on the high end the Kahles needs to be about 2x lower than the ZCO.

    Similarly, the ZCO looks like it needs to be ~0.5x lower on low mag to have the same FoV as the new Kahles, the ZCO needs to be about 1x lower than the new Kahles in the mid-range magnification levels, and the ZCO needs to be about 2x lower than the new Kahles on the high end.

    View attachment 7528693

    I'd update the chart, for Kahles, the # is m at 100m, so if you're going to convert it to feet, you'll also need to scale the 100m to 100y.

    So at 100yards it should be 23.1 feet FoV at 5x
    And at 100yards it should be 4.8 feet FoV at 25x
     
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    Glassaholic

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    I like the design of the parallax spinner with the numbers on top, it appears to be removeable with hex key (hopefully the same size as the turret adjustment since Kahles provides a hex tool in the windage cap). It also appears they have removed the double turn numbers and made the made turret numbers larger, one of my gripes on my TT is the tiny numbers.

    1610734634573.png
     

    koshkin

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    That's an interesting development and a welcome one. I'll need to find a way to get my hands on one.

    I wonder if there are any other changes with the optical system.

    To answer an earlier question: Field of view in angular units changes linearly with magnification if eye relief is constant. It has nothing to do with the area of the circle. However, almost all magnification rings are engraved so that he marked magnification is not necessarily the magnification you are on. Low and high magnifications are usually pretty close.

    ILya
     
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    918v

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    That's an interesting development and a welcome one. I'll need to find a way to get my hands on one.

    I wonder if there are any other changes with the optical system.

    To answer an earlier question: Field of view in angular units changes linearly with magnification if eye relief is constant. It has nothing to do with the area of the circle. However, almost all magnification rings are engraved so that he marked magnification is not necessarily the magnification you are on. Low and high magnifications are usually pretty close.

    ILya

    If they only change the optical system in the ocular (in order to increase FOV), does that affect CA and/or resolution?
     

    littlepod

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    For those running the SKMR4, looking at the reticle lines, the .2 hashes are pretty darn thin as in .1 mil wide. From other reticles I've noticed that .1mils is pretty much invisible to use on the clock unless I'm running at about 18x. Is that similar to what people are seeing using the Kahles SKMR4?
     

    SageRatSafaris

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    I'd update the chart, for Kahles, the # is m at 100m, so if you're going to convert it to feet, you'll also need to scale the 100m to 100y.
    Funny thing about the conversion: you do not need to know there are 1.094 yards per meter. X unit @ 100 unit is the same angular measure whether unit is yards or meters. "10m @ 100m" equals "10yds @ 100yds".
     

    SageRatSafaris

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    Am I dumb for asking why the FOV ratio is less than the power ratio? What happened to "half the power, double the FOV"?

    Kahles 5-25Kahles 5-25 DLRZCO 5-27
    reported FOV21.3-4.5 ft @ 100 yds23.10-4.8 ft @ 100 yds21-4.5 ft @ 100 yds
    FOV ratio21.3/4.5 = 4.733323.1/4.8 = 4.812521/4.5 = 4.6667
    Power ratio25/5 = 525/5 = 527/5 = 5.4
    Shouldn’t this equal 1?4.7333/5 = 0.9474.8125/5 = 0.9634.6667/5.4 = 0.864
     

    koshkin

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    Am I dumb for asking why the FOV ratio is less than the power ratio? What happened to "half the power, double the FOV"?

    Kahles 5-25Kahles 5-25 DLRZCO 5-27
    reported FOV21.3-4.5 ft @ 100 yds23.10-4.8 ft @ 100 yds21-4.5 ft @ 100 yds
    FOV ratio21.3/4.5 = 4.733323.1/4.8 = 4.812521/4.5 = 4.6667
    Power ratio25/5 = 525/5 = 527/5 = 5.4
    Shouldn’t this equal 1?4.7333/5 = 0.9474.8125/5 = 0.9634.6667/5.4 = 0.864

    There are potentially other things in play. For example, if eye relief changes this could be a little different. Also, keep in mind that the FOV is linear in angular units. It is close in linear units, but still an approximation.

    Lastly, I pulled up my notes from when I tested the ZCO and I measure the FOV on 27x as 14 mrad, which is 4.3ft @100 yards and 70 mrad or 21ft on 5x.

    ILya
     

    MarkyMark007

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    will this new FOV mean that optics is better, DOF is better, and it will be easier to get behind the scope, like in others alpha scopes?
    or we must wait and see how it is performing?

    or just buy cheaper regular K525i for Kahles best mechanic and 16 MIL turn knob?
     
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