Parallax

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bubblerboy64

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Jul 25, 2018
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Pa, United States
I’ve noticed or I am at least suspicious that parallax adjustments are more critical to aligning POA and POI using FFP scopes. 

Or am I delusional? 

I was shooting my RAW 30 cal at 100 and getting groups but every time I changed target location a couple ft right or left up or down my point of impact changed. Using a FFP Athlon Helios scope. Switch to a Nikon SFP and didn’t seem to have the problem.

Of course it’s always difficult to eliminate all other variables but just thought I throw this out there for opinions.
 
Very interesting observation but it seems parallax minimization would be important for either type scope. Could it be that the Nikon "focus" range is a little more forgiving than the Athlon and more concentration is needed to correctly focus the Athlon? Is it possible that FFP doesn't focus as easily as SFP? Don't know but it is interesting question.
 
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I like the FFP however the reticle gets small at hunting power levels. Somewhat defeating the advantage of them. Some times the path to perfection has pot holes in it. Have to learn to use what I have.
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That's the answer right there. I think most people know someone who can pick up a meh rifle with crap optics and outshoot the guy with the nice gun and pricey glass. I think it's kind of like letting the perfect be the enemy of the good. We are seeing these folks on YouTube doing some nice shooting with everyday gear. Says here you can get great results by maximizing what you're doing with what you have on hand.

I'm just learning about the focal plane issues. It's all somewhat daunting to the newb, but the more I learn the more money this hobby is going to cost me. So maybe I really don't want to know how much better that scope there, or this one here, looks than mine.
 
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I’ve noticed or I am at least suspicious that parallax adjustments are more critical to aligning POA and POI using FFP scopes. 

Or am I delusional? 

I was shooting my RAW 30 cal at 100 and getting groups but every time I changed target location a couple ft right or left up or down my point of impact changed. Using a FFP Athlon Helios scope. Switch to a Nikon SFP and didn’t seem to have the problem.

Of course it’s always difficult to eliminate all other variables but just thought I throw this out there for opinions.
Click to expand...

I have an Athlon Helos 6-24x50. You are correct in that the parallax error can be significant. I shot two HFT matches recently while I was in England, using that scope. I set the parallax to 23yds and magnification to 9x-10x. No scope adjustment is allowed once the match starts. Lots of targets were in the 35-45 yard range. Parallax error was huge. Even with the gun rested, any head movement would change the location of the reticle. It was near impossible to tell if I was actually on the target for far shots. When adjusted correctly, the Helos has no parallax error. The obvious changes to focus (and parallax error) actually make it work well for AAFTA Hunter Division where we are allowed to focus range find, but those same qualities made it a poor choice for HFT.
 
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I have a question about the FFP Athlon Helios scope. How is it adjusted? 

If you sight in on a 1" dot at 200 - 300 yards, then move your head up and down or side to side, does it stay rock solid? 

Or do the cross hairs move off target a little. Zero movement is mandatory. 

I have a FFP scope that I had to spin the adjustment out so far, the cross hairs look like crap. 

Other wise the cross hairs went off target when I moved my head around. 

That's what it took the get it right though. But at 300 yards it's rock solid. 

I learned a valuable lesson with that scope.

Just turning the eye piece until the cross hairs look best isn't going to cut it. 

This may not be what you're asking exactly. Just seems to be a big thing not all of us are aware of. 


 
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I have a question about the FFP Athlon Helios scope. How is it adjusted? 

If you sight in on a 1" dot at 200 - 300 yards, then move your head up and down or side to side, does it stay rock solid? 

Or do the cross hairs move off target a little. Zero movement is mandatory. 

I have a FFP scope that I had to spin the adjustment out so far, the cross hairs look like crap. 

Other wise the cross hairs went off target when I moved my head around. 

That's what it took the get it right though. But at 300 yards it's rock solid. 

I learned a valuable lesson with that scope.

Just turning the eye piece until the cross hairs look best isn't going to cut it. 

This may not be what you're asking exactly. Just seems to be a big thing not all of us are aware of. 

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Seems you are going about this incorrectly. The eyepiece should only be used to focus the retical ("cross hairs") ONCE unless your vision changes. Most recommend looking at a patch of clear sky and adjusting the eyepiece so that the retical is sharp. After that the side focus is used for distance adjustment, not the eyepiece. I've never heard that this should vary from FFP to SFP.
 
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bandg - Seems you are going about this incorrectly. The eyepiece should only be used to focus the retical ("cross hairs") ONCE unless your vision changes. Most recommend looking at a patch of clear sky and adjusting the eyepiece so that the retical is sharp.

I'm very well aware of the normal recommended set up. 

I did that. No good. Move your head and off goes the recital. Like 1" off each way at a 100 yards. 

Almost returned the scope. Then I found that sweet spot. 

I shoot mostly at 175 - 280 yards. A recital needs to remain centered no matter how far off center your head is behind the scope if you want to hit anything consistently at that range. Everyone is aware of that I'm sure. But how many of us have an optically centered scope that was properly shimmed in the rings. Or checked what I'm pointing out here. 

I'd bet that 50% of the forum members would be very surprised to find that their "clear recital" will move around if they aren't centered behind their scope. 

1/2" movement at 200 yards is totally unexceptable.

Hope that makes sense.




 
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I'm very well aware of the normal recommended set up. 

I did that. No good. Move your head and off goes the recital. Like 1" off each way at a 100 yards. 

Almost returned the scope. Then I found that sweet spot. ...
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I usually use the ocular to only adjust the reticle clarity, and that's it - just once, before I take any other scope readings. I would not normally use the ocular to dial out parallax. The AO (front or side) is used to dial out the parallax. Hopefully, the "zero" parallax error corresponds to the clearest target image, and a clear reticle image. Though I have had at least one scope where they did not seem to match up, so I fudged the ocular some at it seemed to the reduce parallax at the clearest target focus. Whatever works...


 
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bandg - Seems you are going about this incorrectly. The eyepiece should only be used to focus the retical ("cross hairs") ONCE unless your vision changes. Most recommend looking at a patch of clear sky and adjusting the eyepiece so that the retical is sharp.

I'm very well aware of the normal recommended set up. 

I did that. No good. Move your head and off goes the recital. Like 1" off each way at a 100 yards. 

Almost returned the scope. Then I found that sweet spot. 

I shoot mostly at 175 - 280 yards. A recital needs to remain centered no matter how far off center your head is behind the scope if you want to hit anything consistently at that range. Everyone is aware of that I'm sure. But how many of us have an optically centered scope that was properly shimmed in the rings. Or checked what I'm pointing out here. 

I'd bet that 50% of the forum members would be very surprised to find that their "clear recital" will move around if they aren't centered behind their scope. 

1/2" movement at 200 yards is totally unexceptable.

Hope that makes sense.



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It doesn't make sense to me as described because I've never seen such a problem. Not that it couldn't happen but it would seem that it would be a problem with the scope as I don't believe it is designed to function as you describe. Could be wrong though. Hope you figure it out.
 
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I usually use the ocular to only adjust the reticle clarity, and that's it - just once, before I take any other scope readings. I would not normally use the ocular to dial out parallax. The AO (front or side) is used to dial out the parallax. Hopefully, the "zero" parallax error corresponds to the clearest target image, and a clear reticle image. Though I have had at least one scope where they did not seem to match up, so I fudged the ocular some at it seemed to the reduce parallax at the clearest target focus. Whatever works...

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Scotchmo - describes what I'm trying to say perfectly here with proper terminology. 

I too had to fudge the ocular some as it seemed to the reduce parallax at the clearest target focus. 




 
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Speaking of parallax and the Helos, have any of you noticed depending on which way you start the rotation of the parallax dial it affects the clarity of say, a certain distance. Example, here are two pics of me trying to find the best and clearest view at 40 yards. If I start from zero yards and move the dial, 40 yards is best just after the 25 yard mark. If I go past it all the way to infinity and dial backwards back to 40 it’ll show the clearest just past 50 at the midpoint of 25 and 50 yards. If I try and move it closer to the 25 yard mark where it was clearest originally it looks as if I’ve got soda pop glasses on.

Have any of you noticed that? It happens that way with any yardage, too. So I have to tell myself for the sake of consistency to dial back to 0 yards and start from there. If I’m shooting a target at say 60 yards, and a target at say 35 yards shows up, I can’t just dial backwards. I have to quickly dial back to 0 then climb back towards 35 till it clears up.



1566831603_3687224255d63f3f3f2c326.68756132_A52A7A1E-24EC-496D-9B55-A5172A0E9A31.jpeg
1566831604_19114269135d63f3f46e2ee4.14185554_18E13CEC-9373-43CD-B321-87724476D0ED.jpeg

 
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Speaking of parallax and the Helos, have any of you noticed depending on which way you start the rotation of the parallax dial it affects the clarity of say, a certain distance. Example, here are two pics of me trying to find the best and clearest view at 40 yards. If I start from zero yards and move the dial, 40 yards is best just after the 25 yard mark. If I go past it all the way to infinity and dial backwards back to 40 it’ll show the clearest just past 50 at the midpoint of 25 and 50 yards. If I try and move it closer to the 25 yard mark where it was clearest originally it looks as if I’ve got soda pop glasses on.

Have any of you noticed that? It happens that way with any yardage, too. So I have to tell myself for the sake of consistency to dial back to 0 yards and start from there. If I’m shooting a target at say 60 yards, and a target at say 35 yards shows up, I can’t just dial backwards. I have to quickly dial back to 0 then climb back towards 35 till it clears up.



1566831603_3687224255d63f3f3f2c326.68756132_A52A7A1E-24EC-496D-9B55-A5172A0E9A31.jpeg
1566831604_19114269135d63f3f46e2ee4.14185554_18E13CEC-9373-43CD-B321-87724476D0ED.jpeg
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Interesting. Does it seem to be accurate/repeatable if you start from 0 each time?
 
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Yes. After I posted this here I sent an email to Athlon to see maybe if something is loose in the parallax gearing. I also asked them why so far off with the numbers? I expect once I start dialing and I want clear at 40 yards, it should be like at the top pic every time. Even at other distances chosen, it’s way off. My Monstrum G3 scopes side focus on my Bully is dead on with the parallax wheel and a range finder, along with my Vortex Diamondback parallax dial at the objective part of the scope to a range finder. 



This Helos scope has great glass and the locking turret system is awesome and all things turn smoothly, it’s only stink of mine is the parallax wheel and it’s settings.
 
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Yes. After I posted this here I sent an email to Athlon to see maybe if something is loose in the parallax gearing. I also asked them why so far off with the numbers? I expect once I start dialing and I want clear at 40 yards, it should be like at the top pic every time. Even at other distances chosen, it’s way off. My Monstrum G3 scopes side focus on my Bully is dead on with the parallax wheel and a range finder, along with my Vortex Diamondback parallax dial at the objective part of the scope to a range finder. 



This Helos scope has great glass and the locking turret system is awesome and all things turn smoothly, it’s only stink of mine is the parallax wheel and it’s settings.
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I know that a scope is not a range finder per se. But when using my Helos as such, it does seem to give more consistent readings when coming from the same direction. I have read that is the best way to do it. I am having good results starting high and going lower. When I was using a Monstrum G1, I just turned the wheel back and forth until best focus, and it did not seem to matter much. Both scopes have very little backlash in the mechanism.
 
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I have an empty bucket that has a lot of writing on it, all different lettering sizes. I set that bucket out alongside a 100’ tape measure that starts at 30 yards. That bucket get moved at every 30’ or 10 yard increment, and what I do next is range that bucket with my rangefinder. Once I see that that is, say at 40 yards out, I use my scope, and dial in that side wheel till I can read the finest of lettering on that bucket. When it is at it clearest, that’s when I look at the sidewheel to see what yardage is noted. The pics I posted earlier is exactly what I was doing when I pulled up those different readings on the scope, at 40 yards. Ranging a bucket measured out, to verify accuracy with my rangefinder, then dialing in my parallax for the clearest picture at 40 yards.



”Backlash”- good word. That’s exactly what I have going on, except in excess of.
 
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