If twist my parallax knob until the focus is sharp I still have a small amount of parallax error. I've tried to cheat it a bit using the occular focus but that doesn't seem to make much difference. Is this a common problem? The scope is a Bushnell 6x24 G2DMR.
Rifle Scopes Sharp Focus at correct parallax?
- Thread starter jrm850
- Start date
Re: Sharp Focus at correct parallax?
I would say you're working against yourself. Unless you are switching on and off glasses/contacts, the diopter on the eye piece should be left alone (that will make spherical corrections for visual acuity and is used to focus the reticle). I may be mistaken, but I don't believe it can make cylindrical corrections.
Personally, when adjusting for parallax, I check both the vertical and horizontal axis. its often recommended to adjust from the infinity position moving forward. I often start at the bottom end and travel slightly past and back down. There's usually a small window of movement in adjustment that's parallax free. The top end (as I understand) is to account for lash or movement from recoil that would reintroduce parallax error.
Although in theory a scope should have its best picture by this, I don't believe that's always the case, and not at all distances. It shouldn't be out of focus, but having a parallax free image is more important than appearing being marginally more focused. Sometimes within that small adjustment there's a point that may appear better. If you have a stiff parallax, I would go with that if its noticeable. The parallax adjustment changes focal distance, sometimes at intermediate distances, nearby objects may not appear as sharp depending on the scope, magnification etc..
Make sure when adjusting the diopter, you are not trying to focus through the scope too long. It should be done in small increments. With too much time behind it your eye will attempt to focus an image that's not right for you. It may be that you have initially adjusted out of your vision and are straining.
If you feel like your picture and parallax changes during/after shooting it may too close to the edge. If you can't get both a clear and free image to start, I would begin anew. If the whole spectrum of your adjustment that creates a parallax free image is not in focus something's wrong.
Hope that helps,
Good luck-
I would say you're working against yourself. Unless you are switching on and off glasses/contacts, the diopter on the eye piece should be left alone (that will make spherical corrections for visual acuity and is used to focus the reticle). I may be mistaken, but I don't believe it can make cylindrical corrections.
Personally, when adjusting for parallax, I check both the vertical and horizontal axis. its often recommended to adjust from the infinity position moving forward. I often start at the bottom end and travel slightly past and back down. There's usually a small window of movement in adjustment that's parallax free. The top end (as I understand) is to account for lash or movement from recoil that would reintroduce parallax error.
Although in theory a scope should have its best picture by this, I don't believe that's always the case, and not at all distances. It shouldn't be out of focus, but having a parallax free image is more important than appearing being marginally more focused. Sometimes within that small adjustment there's a point that may appear better. If you have a stiff parallax, I would go with that if its noticeable. The parallax adjustment changes focal distance, sometimes at intermediate distances, nearby objects may not appear as sharp depending on the scope, magnification etc..
Make sure when adjusting the diopter, you are not trying to focus through the scope too long. It should be done in small increments. With too much time behind it your eye will attempt to focus an image that's not right for you. It may be that you have initially adjusted out of your vision and are straining.
If you feel like your picture and parallax changes during/after shooting it may too close to the edge. If you can't get both a clear and free image to start, I would begin anew. If the whole spectrum of your adjustment that creates a parallax free image is not in focus something's wrong.
Hope that helps,
Good luck-
Re: Sharp Focus at correct parallax?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jrm850</div><div class="ubbcode-body">If twist my parallax knob until the focus is sharp I still have a small amount of parallax error. I've tried to cheat it a bit using the occular focus but that doesn't seem to make much difference. Is this a common problem? The scope is a Bushnell 6x24 G2DMR. </div></div>
It's normal and common place for all scopes regardless of price and yes I wish it wasn't the case.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jrm850</div><div class="ubbcode-body">If twist my parallax knob until the focus is sharp I still have a small amount of parallax error. I've tried to cheat it a bit using the occular focus but that doesn't seem to make much difference. Is this a common problem? The scope is a Bushnell 6x24 G2DMR. </div></div>
It's normal and common place for all scopes regardless of price and yes I wish it wasn't the case.
Re: Sharp Focus at correct parallax?
Thank you both for the information. I'll try coming at the parallax point from both sides to see if there is better spot in the backlash. It's on a heavy 6br so I haven't noticed any shifts in focus or parallax from recoil.
I'm surprised to hear that even the high dollar scopes suffer from this. People split hairs over the quality of the glass but what is the difference if you can't have sharp focus where you need it?
I don't recall this happening on the fixed power Leupold BR scope that this replaced but maybe that is because it is easier to tune on a fixed.
To adjust the occular, I look through it and quickly twist until the crosshair becomes fuzzy and mark that spot. I do the same thing again on the other side of focus and mark that spot. then I split the difference between the two marks. Is this a good method or is it better to just do quick looks and minor adjustments?
Thank you both for the information. I'll try coming at the parallax point from both sides to see if there is better spot in the backlash. It's on a heavy 6br so I haven't noticed any shifts in focus or parallax from recoil.
I'm surprised to hear that even the high dollar scopes suffer from this. People split hairs over the quality of the glass but what is the difference if you can't have sharp focus where you need it?
To adjust the occular, I look through it and quickly twist until the crosshair becomes fuzzy and mark that spot. I do the same thing again on the other side of focus and mark that spot. then I split the difference between the two marks. Is this a good method or is it better to just do quick looks and minor adjustments?
Re: Sharp Focus at correct parallax?
Ocular Focus: There are several methods floating around, but the best and most logical is using "a cloudless sky" as the background. Some say use a target, and others say use a blank wall. The problem with these methods is your eye will tend to focus on the background - even on a cloud in the sky. If scope has adjustable parallax, set at infinity. Bring the scope to eye looking at a cloudless sky and set ocular to obtain the sharpest reticle.
JRM, your last paragraph was very close to the procedure, except use the "cloudless sky" for the background. Don't stare at reticle, quickly glance at it.
Kevin
Ocular Focus: There are several methods floating around, but the best and most logical is using "a cloudless sky" as the background. Some say use a target, and others say use a blank wall. The problem with these methods is your eye will tend to focus on the background - even on a cloud in the sky. If scope has adjustable parallax, set at infinity. Bring the scope to eye looking at a cloudless sky and set ocular to obtain the sharpest reticle.
JRM, your last paragraph was very close to the procedure, except use the "cloudless sky" for the background. Don't stare at reticle, quickly glance at it.
Kevin
Re: Sharp Focus at correct parallax?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jrm850</div><div class="ubbcode-body"> To adjust the occular, I look through it and quickly twist until the crosshair becomes fuzzy and mark that spot. I do the same thing again on the other side of focus and mark that spot. then I split the difference between the two marks. Is this a good method or is it better to just do quick looks and minor adjustments?</div></div>
I do this, but what I do once I find the limits is to adjust it fuzzy with positive focus and then adjust back until just clear, then I give it about another turn, give or take, but not nearly so much as to put it out of focus the other way. This gives the individual the sharpest image, see, having it split evenly between the two might not be the focus that works best with your eyes (the focus is to make up for small differences in vision, or "eye accommodation"). The way I do it should give you a clear reticle no matter what, and more tailored for your vision regardless if you require those "eye accommodations" or not. I also do this :
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ktdls7</div><div class="ubbcode-body">Ocular Focus: There are several methods floating around, but the best and most logical is using "a cloudless sky" as the background. Some say use a target, and others say use a blank wall. The problem with these methods is your eye will tend to focus on the background - even on a cloud in the sky. If scope has adjustable parallax, set at infinity. Bring the scope to eye looking at a cloudless sky and set ocular to obtain the sharpest reticle.
JRM, your last paragraph was very close to the procedure, except use the "cloudless sky" for the background. Don't stare at reticle, quickly glance at it.
Kevin</div></div>
I find the cloudless sky to work best at preventing focus on the background too, works best by far. And yeah, doing it in increments works best.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jrm850</div><div class="ubbcode-body"> To adjust the occular, I look through it and quickly twist until the crosshair becomes fuzzy and mark that spot. I do the same thing again on the other side of focus and mark that spot. then I split the difference between the two marks. Is this a good method or is it better to just do quick looks and minor adjustments?</div></div>
I do this, but what I do once I find the limits is to adjust it fuzzy with positive focus and then adjust back until just clear, then I give it about another turn, give or take, but not nearly so much as to put it out of focus the other way. This gives the individual the sharpest image, see, having it split evenly between the two might not be the focus that works best with your eyes (the focus is to make up for small differences in vision, or "eye accommodation"). The way I do it should give you a clear reticle no matter what, and more tailored for your vision regardless if you require those "eye accommodations" or not. I also do this :
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ktdls7</div><div class="ubbcode-body">Ocular Focus: There are several methods floating around, but the best and most logical is using "a cloudless sky" as the background. Some say use a target, and others say use a blank wall. The problem with these methods is your eye will tend to focus on the background - even on a cloud in the sky. If scope has adjustable parallax, set at infinity. Bring the scope to eye looking at a cloudless sky and set ocular to obtain the sharpest reticle.
JRM, your last paragraph was very close to the procedure, except use the "cloudless sky" for the background. Don't stare at reticle, quickly glance at it.
Kevin</div></div>
I find the cloudless sky to work best at preventing focus on the background too, works best by far. And yeah, doing it in increments works best.
Re: Sharp Focus at correct parallax?
I often find the ocular setting can be improved upon after the initial "white wall" or "cloudless sky" setting with sidefocus scopes.
When aiming at a target 100-200 yds away or so, remove parallax completely. Then if the target and reticle are not focused together, turn the ocular until they are. It's much easier to do with fast-focus eyepieces.
When focusing the ocular at the sky, etc, there can often be a wide range of acceptable settings. My eye seems more discerning when trying to focus on an actual target and the reticle at the same time so I think I just get a more accurate setting. If the target and reticle are slightly out of focus with each other it can be very annoying.
I often find the ocular setting can be improved upon after the initial "white wall" or "cloudless sky" setting with sidefocus scopes.
When aiming at a target 100-200 yds away or so, remove parallax completely. Then if the target and reticle are not focused together, turn the ocular until they are. It's much easier to do with fast-focus eyepieces.
When focusing the ocular at the sky, etc, there can often be a wide range of acceptable settings. My eye seems more discerning when trying to focus on an actual target and the reticle at the same time so I think I just get a more accurate setting. If the target and reticle are slightly out of focus with each other it can be very annoying.
Re: Sharp Focus at correct parallax?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jon A</div><div class="ubbcode-body">I often find the ocular setting can be improved upon after the initial "white wall" or "cloudless sky" setting with sidefocus scopes.
When aiming at a target 100-200 yds away or so, remove parallax completely. Then if the target and reticle are not focused together, turn the ocular until they are. It's much easier to do with fast-focus eyepieces.
When focusing the ocular at the sky, etc, there can often be a wide range of acceptable settings. My eye seems more discerning when trying to focus on an actual target and the reticle at the same time so I think I just get a more accurate setting. If the target and
reticle are slightly out of focus with each other it can be very annoying. </div></div>
+1
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jon A</div><div class="ubbcode-body">I often find the ocular setting can be improved upon after the initial "white wall" or "cloudless sky" setting with sidefocus scopes.
When aiming at a target 100-200 yds away or so, remove parallax completely. Then if the target and reticle are not focused together, turn the ocular until they are. It's much easier to do with fast-focus eyepieces.
When focusing the ocular at the sky, etc, there can often be a wide range of acceptable settings. My eye seems more discerning when trying to focus on an actual target and the reticle at the same time so I think I just get a more accurate setting. If the target and
reticle are slightly out of focus with each other it can be very annoying. </div></div>
+1
Re: Sharp Focus at correct parallax?
If you wear corrective lenses EXCEPT when you shoot you can correct with the ocular adjustment. But, if you have astigmatism the ocular adjustment can't correct for that.
If you wear corrective lenses EXCEPT when you shoot you can correct with the ocular adjustment. But, if you have astigmatism the ocular adjustment can't correct for that.
Re: Sharp Focus at correct parallax?
I'm no optics engineer but this phenomenon boils my gourde too.
Parallax-free does NOT always mean sharply in focus. This has been my experience with 2 Benders, 2 NFs, a Leupold, a March, and 4 Premiers. I accept (reluctantly) physics does not allow for focus and zero parallax to coincide, but I fucking hate it.
Does anyone understand the physics behind this?
I'm no optics engineer but this phenomenon boils my gourde too.
Parallax-free does NOT always mean sharply in focus. This has been my experience with 2 Benders, 2 NFs, a Leupold, a March, and 4 Premiers. I accept (reluctantly) physics does not allow for focus and zero parallax to coincide, but I fucking hate it.
Does anyone understand the physics behind this?
Re: Sharp Focus at correct parallax?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body">I'm no optics engineer but this phenomenon boils my gourde too.
Parallax-free does NOT always mean sharply in focus. This has been my experience with 2 Benders, 2 NFs, a Leupold, a March, and 4 Premiers. I accept (reluctantly) physics does not allow for focus and zero parallax to coincide, but I fucking hate it.
<span style="color: #FF0000">Does anyone understand the physics behind this?</span> </div></div>
Well, I thought I had it figured out.
I sold a couple of perfectly good NF scopes and bought a better 5.5-25x56 scope.
Geez!!
Better glass for my old eyes, great turrets, and a "zero stop" within about .5 mils of my NF ZS, and the diopter focus is very easy to set up.
The parallax adjustment focuses perfectly with absolutely no parallax on the reticle at just slightly past the 300 mark on the 328 yard targets at my range.
Perfect!!
So I buy another IDENTICAL scope for my other rifle.
The diopter focus is about a quarter turn different from the first scope.
My 328 yard targets are completely out of focus at the same 300 yard parallax adjustment setting on this identical scope.
I have to dial the parallax adjustment to the 600 yard setting to get the image to focus and the parallax out of the reticle.
I called the manufacturer and they said it was a common problem, but if I would send the scope in they would take a look at it.
No complaints on my part. I'll probably send the scope in and I'm sure they'll get things right, but I just don't understand the "physics" behind this either.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body">I'm no optics engineer but this phenomenon boils my gourde too.
Parallax-free does NOT always mean sharply in focus. This has been my experience with 2 Benders, 2 NFs, a Leupold, a March, and 4 Premiers. I accept (reluctantly) physics does not allow for focus and zero parallax to coincide, but I fucking hate it.
<span style="color: #FF0000">Does anyone understand the physics behind this?</span> </div></div>
Well, I thought I had it figured out.
I sold a couple of perfectly good NF scopes and bought a better 5.5-25x56 scope.
Geez!!
Better glass for my old eyes, great turrets, and a "zero stop" within about .5 mils of my NF ZS, and the diopter focus is very easy to set up.
The parallax adjustment focuses perfectly with absolutely no parallax on the reticle at just slightly past the 300 mark on the 328 yard targets at my range.
Perfect!!
So I buy another IDENTICAL scope for my other rifle.
The diopter focus is about a quarter turn different from the first scope.
My 328 yard targets are completely out of focus at the same 300 yard parallax adjustment setting on this identical scope.
I have to dial the parallax adjustment to the 600 yard setting to get the image to focus and the parallax out of the reticle.
I called the manufacturer and they said it was a common problem, but if I would send the scope in they would take a look at it.
No complaints on my part. I'll probably send the scope in and I'm sure they'll get things right, but I just don't understand the "physics" behind this either.
The latest issue of "Sniper" magazine has a small bit on this issue, inside the "Long Range Myths" article...
The author claims most shooters use thier parallax knob incorrectly. He claims shooters will adjust their ocular lens until the reticle looks crisp and bright when looking up into the sky, and then adjust the parallax knob while wiggling their head to and fro, until the reticle doesn't move on the target - even if the image in the scope isn't perfectly in focus.
He says this is wrong.
If this is wrong, what is RIGHT?
I've spent a decent chunk of time at the range messing with my ocular & parallax knobs trying to find a perfect balance to get perfect focus and "parallax free" to coincide at the same point, and I've never found it. With a really whacked ocular setting I can get it close at *some* distances, but not all. The reticle is hard to keep in focus for my eyes with the really whacked ocular setting.
For what it's worth, this has been the case with every scope I've had including S&B, Premier, March, NF and Leupold. I have 20/30 vision in my left eye, and 20/20 in my right (scope) eye. I don't have an astigmatism. My eyes are good to go.
WTF?
The author claims most shooters use thier parallax knob incorrectly. He claims shooters will adjust their ocular lens until the reticle looks crisp and bright when looking up into the sky, and then adjust the parallax knob while wiggling their head to and fro, until the reticle doesn't move on the target - even if the image in the scope isn't perfectly in focus.
He says this is wrong.
If this is wrong, what is RIGHT?
I've spent a decent chunk of time at the range messing with my ocular & parallax knobs trying to find a perfect balance to get perfect focus and "parallax free" to coincide at the same point, and I've never found it. With a really whacked ocular setting I can get it close at *some* distances, but not all. The reticle is hard to keep in focus for my eyes with the really whacked ocular setting.
For what it's worth, this has been the case with every scope I've had including S&B, Premier, March, NF and Leupold. I have 20/30 vision in my left eye, and 20/20 in my right (scope) eye. I don't have an astigmatism. My eyes are good to go.
WTF?
