I continue to think the detent, or alternately the locking turret, idea is a really good one.
Rifle Scopes Why do you think an adjustable parallax feature is needed on LPVOs? ? ?
- Thread starter Terry Cross
- Start date
Nightforce's first offering did not have parallax adjustment. The original Razor didn't either (assaulters chose NOT to have to juggle with it. The older Schmidt-Bender didn't adjust. The Marines' new 1-8 Squad Common Optic has fixed parallax. For a troop who needs to aim-and-shoot to 200-300 yards, again, parallax adjustment is NOT required.
USAMU shooters specify what it is they will buy. Like in any other sport or activity the crowd will follow the winner (or at least the guy who has a basis for subject matter expertise). Somebody looking to get quick hits probably doesn't need parallax adjustment. Someone trying to hit a prone machine-gunner or automatic grenade launcher in the head or upper torso might want to dial out parallax.
It might be a big enough difference if you have a scope with fixed 100-yard or 200-yard parallax. My kid was leaking shots out of the X-ring at 600-yards at Benning before he switched from Razor back to March based on feedback he was getting from the rifle team coach and NCOIC.
USAMU's LPVO / M16-M4 requirement is to kill X-rings in 500- and 600-yard slow fire; hit X-rings at 1,000-yards with a 20-inch 7.62mm, slow fire; and get as many E-type hits with an M-16 and M4 at 600- and 500-yards in 50 seconds or less at either range.
I don't know of any scope with a locking parallax adjustment knob.
An LPVO is a poor observation device.
Last edited:
The March-FX 5-42X56 HM has a locking side focus knob. It is a rather unique feature.
Just an FYI the S&B dual focal with CC mode. it has a CC detent on the zoom vario ring that changes the parrallax of the 1x to 7meters.
It was fairly recent that I listened to it. I remember @Dthomas3523 was kinda taken back a bit by it. So it stuck with me who and what was involved.
The nxs not having adjustable parallax was a shortcoming, not a value added. The older Schmidt was a 1-4 and again is an orange when we’re taking about apples. I don’t care about what usmc requirement writers think their infantryman need.
On this war fighting TANGENT (which is what this is because nobody cares): an OPTIC doesn’t NEED to be a poor observation device. If you think that the small arms kill chain cannot be enhanced by making the rifle optic a more capable observation tool, then I don’t know what to tell you. Not every squad is going to carry binos, but every squad will carry many many rifle optics.
Nobody has suggested the marine corps edit their requirements for their new optic to include adjustable parallax.
If we really want to get down into this warfighting rabbit hole especially on the cutting edge, the conversation needs to move into night vision, night optics, modern communication enhancements, and lasers. Warfighting is NOT the subject
How so? Like most shit, it boils down to application. Let’s take daylight bright reticle off the table for now, and not worry about 1x and just talk parallax and sight picture. Take a 3.5x10 M3 for example. Not an LPVO but falls into the current top end of the mag range now. If you have parallax set or (if you could) locked at 100 or 125 yards when you get to 400 your looking at a very soft image and at 500+ it’s just a blob. If you were using said scope for multiple, varying distance engagements or say you’re hunting and the Granddaddy if all Coyotes comes up at 440y while your parallax is locked at 100 you will have to move that parallax to get a sight picture and engage, perfect head position or not. Changing to a fixed parallax ends this. Are they as accurate, nope. But for what an LPVO is for it works.
Edit: I’m sure there are examples to contradict this. A fixed 10x Unertl for example, but I think the point remains.
If you’re not using the LPVO as a rapid engagement scope, why use an LPVO? Just put a full power, fully optioned scope on and be done with it.
But, as I said. Nice to have choices. To each their own...
Last edited:
It makes it moot because current optics are fixed. A locking turret just lets you fix it to whatever you want. I would prefer it if my scope was fixed to 200 (what many people zero their AR scopes at)
Every scope is a rapid engagement tool...
Manufacturers are going to build what makes money. The institutional Army and Marine Corps generally wants to outfit squaddies with cheap and durable capability.
SOCOM has driven quite a bit of innovation. Nobody wanted to build a 1-4 red dot with a military reticle -- except for Schmidt-Bender, and their lowest power setting is close to 1.1, not 1X -- which bothers/bothered some. Vortex offered their 1-6 Razor after the military had been at war for 10-15 years, while the main force was using ACOGs.
I believe March was the first to offer side-focus / parallax correction for the National Match Course -- for all intents and purposes a sport, since the Army doesn't train soldiers to hit to 500 yards and the Marine Corps standard for qualification counts near-misses for score.
Today you'll have to settle for fixed parallax at what some guy says they're going to be set for at the factory; buy something like a March with side-focus/parallax adjustment; or convince a manufacturer to build you an adjustable-lockable or capped parallax capability.
A Nightforce engineer I worked with once told me, "I can build you perfect -- but you can't afford it." He then explained to me how he built the best compromise for what we were asking and what we were willing to pay for -- which was different than what they offered to the civilian market.
Terry's point for the masses is correct -- for the majority of the market (to include military buyers) they won't notice parallax error for the distances and ammunition most will shoot.
SOCOM has driven quite a bit of innovation. Nobody wanted to build a 1-4 red dot with a military reticle -- except for Schmidt-Bender, and their lowest power setting is close to 1.1, not 1X -- which bothers/bothered some. Vortex offered their 1-6 Razor after the military had been at war for 10-15 years, while the main force was using ACOGs.
I believe March was the first to offer side-focus / parallax correction for the National Match Course -- for all intents and purposes a sport, since the Army doesn't train soldiers to hit to 500 yards and the Marine Corps standard for qualification counts near-misses for score.
Today you'll have to settle for fixed parallax at what some guy says they're going to be set for at the factory; buy something like a March with side-focus/parallax adjustment; or convince a manufacturer to build you an adjustable-lockable or capped parallax capability.
A Nightforce engineer I worked with once told me, "I can build you perfect -- but you can't afford it." He then explained to me how he built the best compromise for what we were asking and what we were willing to pay for -- which was different than what they offered to the civilian market.
Terry's point for the masses is correct -- for the majority of the market (to include military buyers) they won't notice parallax error for the distances and ammunition most will shoot.
Last edited:
For the National Match Course some LPVO shooters find they need to put a lens or transparent cap with a simple hole drilled through the center on the eyepiece end of the scope to center their eyeball with the tube's central axis and reticle to accommodate for parallax -- something the average shooter will NEVER need.
For the Leupold:
For the Leupold:
The problem is (or maybe the desired solution ) is adjustable parallax scopes don’t have the target in focus unless the parallax is set for the distance beyond a certain point. For example, If I take a NXS or a mk4 variable and set parallax at 200y you cannot even find a full sized IPSC at 600 because the image beyond say 500 yards is totally out of focus. At a point, every one of the adjustable scopes I have allow me to set set parallax and then shoot out beyond that point without adjusting anymore. Most are around 600y setting. But if I had to quickly switch to anything inside 400 is totally out of focus. How are you overcoming that?
Are must be taking about two totally different animals here? Or I’m way behind the times with new tech as I have. Never seen a scope with adjustable parallax that will have a target in focus from 50y-infinity?
One of the better threads we’ve had.
No, the average shooter will never need that, or an adjustment for parallax...
But at a street price of $2500, many of these LPVO like the ATACR aren’t generally being purchased by the average shooter.
Comments that some have made about other errors like shooter and crappy ammo errors are ridiculous. Of course there are other errors. We try to minimize those too. Are you going to poo-poo guys who seek more accurate ammo? More accurate barrels? The existence of one error doesn’t indicate that we should ignore other errors... possibly the stupidest thing I’ve read all week... and I read the night vision forum
But at a street price of $2500, many of these LPVO like the ATACR aren’t generally being purchased by the average shooter.
Comments that some have made about other errors like shooter and crappy ammo errors are ridiculous. Of course there are other errors. We try to minimize those too. Are you going to poo-poo guys who seek more accurate ammo? More accurate barrels? The existence of one error doesn’t indicate that we should ignore other errors... possibly the stupidest thing I’ve read all week... and I read the night vision forum
Not wanting to put words in your mouth or second guess how you think but would it be safe to say that the guys (call it Group 1) that want to hang out mostly on the high end X of an LPVO could live with having a bottom X in the 2, 2.5, 3x range without truly needing that 1x in your world?
Conversely I fall on the opposite preference (call it Group 2)
I want to hang out mostly on the 1X settings so that my rifle has the same utility as if equipped with Eotech, Aimpoint, etc. style sights but want to be able to creep into a higher X for any extended distance PID/Shot or even get picky with a close/medium range target that is only giving me a piece to hit.
If the above is true for some, I could see some trying to justify the adjustable parallax feature due the higher X and longer distances they spend most of their time on.
I'm just thinking that any product line that has gone through the trouble of developing and delivering a really good 1X but can crank up more X on demand is built for the 2nd group I would fall into while the bigger objective 2-20X, 2.5-10X and 3-16X lines would have a target audience resembling the 1st group.
Is this reasonable to assume in general?
./
Conversely I fall on the opposite preference (call it Group 2)
I want to hang out mostly on the 1X settings so that my rifle has the same utility as if equipped with Eotech, Aimpoint, etc. style sights but want to be able to creep into a higher X for any extended distance PID/Shot or even get picky with a close/medium range target that is only giving me a piece to hit.
If the above is true for some, I could see some trying to justify the adjustable parallax feature due the higher X and longer distances they spend most of their time on.
I'm just thinking that any product line that has gone through the trouble of developing and delivering a really good 1X but can crank up more X on demand is built for the 2nd group I would fall into while the bigger objective 2-20X, 2.5-10X and 3-16X lines would have a target audience resembling the 1st group.
Is this reasonable to assume in general?
./
WWT, my friend. You introduced a concept into this discussion and I think we need to put it in context.
The hyperfocal (one word) distance is a long-understood concept in photography that applies to riflescopes also, of course, but needs to be applied properly. Even in photographic circles, when we discuss the concept of hyperfocal distance, there is always a little bit of discussion on how best to a) calculate it and b) use it.
The hyperfocal distance is the focus setting on a lens that will have the greatest depth of field for your picture (or application). For example, let's say you want to take a focused picture of a car fairly close to you and have the mountains in the background also be in focus. If you focus on the car, the mountains will be out of focus, or at least not as sharp as you would like. The trick is to focus past the car and yet still have the car focused crisply enough for your purposes. As you focus further out, the mountains come into better focus to the point where the car and the mountains are clear enough for your purposes.
Here's a good link for a calculator and some examples:
A Guide to DOF and Hyperfocal Distance - Tables & Calculator
You may have wondered
www.nikonians.org It's a similar concept with a riflescope except that the only control you have is the side focus. No aperture, no shutter, no ISO. But with a riflescope you don't change that from picture to picture, you set you side focus to the distance where the depth of field covers the near and far distance at the level of sharpness that you find acceptable. Let me introduce once again, my friend circle of confusion. This is the guy who signals you that the sharpness of the object in the picture is good enough. Most camera manufacturers and hyperfocal distance calculator use a CoC of .03mm, I prefer to use a CoC value of .02 for my pictures and for my riflescopes on precision rifles. Boy, are we ever getting pedantic here. I can easily calculate the hyperfocal distance for any camera lens, but doing the same for a riflescope is not easy because the manufacturers do not provide the information we need to do that. I keep thinking that I could develop a hyperfocal calculator for riflescopes using the main tube inner diameter, the objective lens diameter and (the tricky part) the focal length of the objective part. Maybe I can derive that from the dimensions of the scope or perhaps just the base magnification and make assumptions about the eyepiece focal length.
Anyway, I digress, and of course, someone will post a link to such a calculator. Anyway. If you want to figure out he hyperfocal distance of your riflescope, the best way would be to set up some targets or objects at various distance with "infinity" in the background like a mountain. Then at low power, use the side focus to find a setting where the nearest object you would usually expect to see clearly, is in acceptable enough focus and the "infinity" background is also in acceptable (to you) focus. Now comes the fun part. Start zooming in. Of course the field of view will quickly reduce but you can point the scope at the near and then the far object, without touching the side focus. The zooming action is essentially decreasing the CoC value in our concept here. As you zoom in on the image the focus becomes more critical and it's up to you to decide what is acceptable to you and at what magnification.
If you have a side focus knob, you should remember or mark the position of the knob that provides the best hyperfocal distance for you, or perhaps just a crisp picture at 100 to 130 yards.
I'm now looking for some aspirin.
No, I don’t think those assumptions are safe or accurate.
if I could live with 3 x on the low end I could stick with my grandpa’s Leupold 3-9 hunting scope. By that same assumption I could suggest that you be happy with 1-4 optics because close range is your focus. Sure, you COULD, but why would you? It’s 2021. We have options.
I can’t speak to the manufacturer’s intent, but I can speak to a segment of the market they are chasing...
Just like the existence of a 1X makes you think that’s the focus, the evolution from 1-4 to 1-6 to 1-8 to 1-10 to? Tells us unmistakably that there is real demand for the SPR capabilities while also having 1X for close range.
The move toward FFP and excellent holding reticles like the DM-X in the ATACR further drive home this point.
Is YOUR use for this scope primarily 1X? Yes. Is MINE? No. And clearly the manufacturers understand that because they keep adding to the top end and the tree reticles.
if I could live with 3 x on the low end I could stick with my grandpa’s Leupold 3-9 hunting scope. By that same assumption I could suggest that you be happy with 1-4 optics because close range is your focus. Sure, you COULD, but why would you? It’s 2021. We have options.
I can’t speak to the manufacturer’s intent, but I can speak to a segment of the market they are chasing...
Just like the existence of a 1X makes you think that’s the focus, the evolution from 1-4 to 1-6 to 1-8 to 1-10 to? Tells us unmistakably that there is real demand for the SPR capabilities while also having 1X for close range.
The move toward FFP and excellent holding reticles like the DM-X in the ATACR further drive home this point.
Is YOUR use for this scope primarily 1X? Yes. Is MINE? No. And clearly the manufacturers understand that because they keep adding to the top end and the tree reticles.
While the above might not be the most popular way to look at it, I think it's a really good idea, at least to tell people to think about before they jump into LPVO as the new in thing.
I think figuring out if you are in group 1 or group 2 would also be very important when choosing what reticle you want to go with on your scope especially if you are doing FFP LPVO
In my case, I got LPVOs for my ARs planning to use them as group 2
So in my case I went with the Primary Arms platinum series as the reticle is good and immediately visible at 1X even without illumination, and still works okay at the 8x setting, so it works well for close range run and popup minute of Antifa as the primary, and then needing better magnification and Target ID sometimes. Basically replacing an Eotech with flip magnifier.
As compared to for example the Vortex Gen III where without illumination, the reticle at 1x especially against a dark or shaded target is much harder to pick up and it's a lot more suited for group 1 who want to do precision shots at distance on the higher magnification settings, or who are doing target shooting at the range.
And then you get the folks wondering about running an offset RDS on their 1x to ??? LPVO and I'm like....
That was a ton of stuff for me to read... What does "WWT" mean?WWT, my friend. You introduced a concept into this discussion and I think we need to put it in context.
The hyperfocal (one word) distance is a long-understood concept in photography that applies to riflescopes also, of course, but needs to be applied properly. Even in photographic circles, when we discuss the concept of hyperfocal distance, there is always a little bit of discussion on how best to a) calculate it and b) use it.
The hyperfocal distance is the focus setting on a lens that will have the greatest depth of field for your picture (or application). For example, let's say you want to take a focused picture of a car fairly close to you and have the mountains in the background also be in focus. If you focus on the car, the mountains will be out of focus, or at least not as sharp as you would like. The trick is to focus past the car and yet still have the car focused crisply enough for your purposes. As you focus further out, the mountains come into better focus to the point where the car and the mountains are clear enough for your purposes.
Here's a good link for a calculator and some examples:
A Guide to DOF and Hyperfocal Distance - Tables & Calculator
You may have wondered
It's a similar concept with a riflescope except that the only control you have is the side focus. No aperture, no shutter, no ISO. But with a riflescope you don't change that from picture to picture, you set you side focus to the distance where the depth of field covers the near and far distance at the level of sharpness that you find acceptable. Let me introduce once again, my friend circle of confusion. This is the guy who signals you that the sharpness of the object in the picture is good enough. Most camera manufacturers and hyperfocal distance calculator use a CoC of .03mm, I prefer to use a CoC value of .02 for my pictures and for my riflescopes on precision rifles. Boy, are we ever getting pedantic here. I can easily calculate the hyperfocal distance for any camera lens, but doing the same for a riflescope is not easy because the manufacturers do not provide the information we need to do that. I keep thinking that I could develop a hyperfocal calculator for riflescopes using the main tube inner diameter, the objective lens diameter and (the tricky part) the focal length of the objective part. Maybe I can derive that from the dimensions of the scope or perhaps just the base magnification and make assumptions about the eyepiece focal length.
Anyway, I digress, and of course, someone will post a link to such a calculator. Anyway. If you want to figure out he hyperfocal distance of your riflescope, the best way would be to set up some targets or objects at various distance with "infinity" in the background like a mountain. Then at low power, use the side focus to find a setting where the nearest object you would usually expect to see clearly, is in acceptable enough focus and the "infinity" background is also in acceptable (to you) focus. Now comes the fun part. Start zooming in. Of course the field of view will quickly reduce but you can point the scope at the near and then the far object, without touching the side focus. The zooming action is essentially decreasing the CoC value in our concept here. As you zoom in on the image the focus becomes more critical and it's up to you to decide what is acceptable to you and at what magnification.
If you have a side focus knob, you should remember or mark the position of the knob that provides the best hyperfocal distance for you, or perhaps just a crisp picture at 100 to 130 yards.
I'm now looking for some aspirin.
I'll admit I was parroting the pod cast that the others were referring too.
Did you listen to it?
Yeah, it's mainly musing, stream of consciousness stuff.
The "WWT" thing is my old hometown idiom for "Not so fast," It's not an insult or a pejorative in any way; it's just very arcane.
I did not listen to the podcast. I didn't spend time looking for it, I just dug in my photography knowledge. If someone can point to the podcast, I may give it a listen.
The "WWT" thing is my old hometown idiom for "Not so fast," It's not an insult or a pejorative in any way; it's just very arcane.
I did not listen to the podcast. I didn't spend time looking for it, I just dug in my photography knowledge. If someone can point to the podcast, I may give it a listen.
I’m pretty sure that those chasing ever higher top end LPVOs are more the 3-gun and other competitors more than the day-to-day grind guys.
That’s how I’m seeing this anyway. Sure, for 1-8 or 1-10, make there be some choices for adjustable parallax. That’s where it matters at all anyway. For my 1-6, what’s the fucking point?
I think it makes sense here to break down groups historically, and then it will establish some clarity.
I’ve seen the LPVO evolve ever since I remember LAV showing me the first 1.1-4x Schmidt & Bender Short Dot back in 2003-2004. I remember it having a FFP reticle, with daylight bright dot illumination. He said they had approached other optics manufacturers and gotten things back that nowhere matched what they had asked for, whereas S&B gave them exactly what they were looking for. As soon as I put my hands on it, I knew I wanted one.
If I recall, one of the main requirements was enabling shooters to get PID on TGTs where Aimpoints provided no advantages over naked eyes.
Right out of the gate, there were 2 initial groups who the LPVO concept were catering to:
Group 1: Free Float Carbines with LPVO for CQB and PID/shooting at distance with BDC for M855 and 75gr BTHP
Group 2: SR-25 7.62 NATO 16” carbines or 20” rifles with BDCs for M118LR (This is the group most commonly overlooked relevant to this discussion I think.)
Group 3:
Prior to this, the Recce and later SPR concepts had come to fruition with various optics solutions (1.25-4x, 2.5-8x36, 3-9x36, 3.5-10x40, 2.5-10x24), but this was for a dedicated light sniper/DMR system that leaned more on distance TGT PID/engagement with a Mini RDS solution getting added later for CQB for some.
As guys realized that the 18” barrel juice wasn’t worth the length/weight penalty squeeze most of the time, some important features from under and on top of the SPR hood were just absorbed into the M4A1 SOPMOD Block II, with good triggers, free float handguards, Mk.262 77gr, and a new line of optics. Some dudes started buying Short Dots and other 1.1-4x LPVOs with their own money or Team funds, even though they already had 1. Trijicon Reflex Sights and 2. TA01 ACOGs from the original SOPMOD package with 1/4 ratio of ACOG to Reflex, 3. Eotech 553s, 4. Aimpoint Comp Ms, 5. Eotech XPS-3s with flip-magnifiers, 6. Elcan Specter DR 1-4x, and 7. ACOGs with 8. Docter Optics RDS piggy backs on their property books.
Given the fact that within SOCOM units, they already had 2 different 4x ACOGs, Eotechs with magnifiers, and the Elcan Specter DR 1-4x as issued items, and still found merit in purchasing LPVOs, it makes you appreciate and look into the LPVO even more. This was sort of a Group 3 that was effectively achieving what Group 1 was doing more-or-less. I think LPVOs basically allowed Block II Carbines to serve better in the same space where SPRs did, without really losing any performance advantages of the carbine in CQM/CQB, with a little top end magnification taken away from the line-up of SPR optics, where 8x was the lowest on the Leupold MR/T options.
Group 4: Civilians and 3-Gunners realized that LPVOs were great for running close-range and intermediate stages that basically validated the LPVO concept in more clean settings on flat ranges and distance shooting stages.
As the desire for more and more top-end magnification followed the chase of more “true 1x” on the bottom end for replacing RDSs, the LPVO expanded into more of a do-all optic.
The two main types of platforms that are often overlooked are the requirements for the SPRs and SR-25s, and the way that higher top-end LPVOs started filling-in where the SPR optics had previously filled a niche.
Essentially, the modern higher magnification factor LPVOs manifesting themselves with the 1-8x and 1-10x units are a combination of multiple optics that previously performed different roles on the carbines with 1-4x, SR-25s and Recce carbines with 1.1-4x or 1-6x, and SPRs with 2.5-10x.
The Vortex Razor Gen III 1-10x is a better optic in both the low end and high end compared with an S&B 1.1-4x20 Short Dot, with better reticle options and excellent bright red dot.
The Razor Gen III 1-10x is also a better light sniper/DM optic than any of the SPR scope options on their high end.
The desire for side focus doesn’t detract from the performance requirements in CQM, but just adds another option for the PID/longer range engagement realm. The modern era of high performance, 10 factor magnification LPVOs are showing that you can really have both ends of the spectrum in a compact optic. You don’t have to be pigeon-holed into a particular group because the optical engineering has allowed you to have the best of both worlds.
Last edited:
The razor 1-10 is better on the lower end than which short dot? the 1.1-4 or the newer 1-8 dual CC?
That’s fair. This hypothetical scope would be a lifecycle replacement for either today’s new 1-8’s or yesterday’s mk6 kits that are poop, come with poop, and are almost a total waste of money. Requirements writers often distort the ground truth requirements. Fact is, if today’s new issue is the fixed focus 1-8, tomorrow’s next issue needs to be better in some way, and I hope that way can be in side focus because at that point, given new barrel coating and ammo, everyone will have basically a sniper rifle.
I personally think issuing every single person a neato scope is as big of a mistake as issuing everyone mlok (good luck with mlok rails not disappearing...). All these neato scopes going to break, they’re going to be slow to replace come total war, and their capabilities can’t even come close to being maximized.
Personally, I would say this hypothetical optic (I personally would write the requirements as low end mag between 1-3 and high end between 10-15) would be a very appropriate lifecycle replacement to the mk6 kits. You won’t need to issue the 700 dollar aimpoint (especially now that every Glock gets an rmr issued with it), the atacr glass is clear to the point where 8 power with an atacr is probably worth 15 power on the mk6, the scope will track, and every single one would get used.
This is a little incorrect. So if you shrink the aperture of an optical system the resulting image has a longer depth of field (more things are in focus with each other). Additionally, this effect (all other things being equal) becomes more apparent at higher magnifications.
I probably butchered the exact terminology/syntax. In the context of these scopes, they’re all fixed at like 125 ish, and you’ll never notice out of focus issues with a 1-6 until you’re trying to refine details at 300+. It starts creeping in way harder at 8x. At 10x it hits hard to the point where I’m personally asking myself what the heck is the point of a 10 power scope without adjustable parallax (unless all you’re doing is 200 and in)
Last edited:
@Terry Cross
Because of you (your fault), I did some quick calculations with SWAG assumptions about settings, where I equivalenced riflescope objectives to camera lenses simply because I can't find formulas or calculators for hyperfocal distance for riflescopes. I looked at my "results" and then played with a March 1-10X24 DR to see if the results made sense. This is all very much "back of the envelope" and "hand-held scope" stuff.
The March 1-10X24 focuses down to 10 yards, like virtually all March scopes. At 1X, regardless of the side focus setting, I could not tell a difference in the picture, either inside the house (even at a few yards) or outside at any distance that you would shoot at 1X. At 2X, that was pretty much the same, except when I was looking very far away and the side focus was set at minimum distance. Same story for 3X and 4X, though the extreme position became more apparent. I found that if I left the focus at infinity, I had no issues outside up to about 6X-7X. I could readily detect a shift in the focus at 4X and above, but the DOF was deep enough to present a very good image at any distance. At 6X or so, the side focus really helped cleaning up the image to what I call "F-class quality" but it did not require much movement of the side focus knob as you would expect. At 8X and above, I could easily clean it up to "FCQ" with a small twist and I was glad to have the side focus.
Moral of the story with the March 1-10X24 (and I suspect many other LPVOs): for quick employment of the optics at low magnification, the side focus setting is irrelevant. If you want the broadest range for 1-5X or 6X, leave it in the middle of the range. Above 6X, where one should have more time to focus, the side focus knob is very handy for fine precision.
Because of you (your fault), I did some quick calculations with SWAG assumptions about settings, where I equivalenced riflescope objectives to camera lenses simply because I can't find formulas or calculators for hyperfocal distance for riflescopes. I looked at my "results" and then played with a March 1-10X24 DR to see if the results made sense. This is all very much "back of the envelope" and "hand-held scope" stuff.
The March 1-10X24 focuses down to 10 yards, like virtually all March scopes. At 1X, regardless of the side focus setting, I could not tell a difference in the picture, either inside the house (even at a few yards) or outside at any distance that you would shoot at 1X. At 2X, that was pretty much the same, except when I was looking very far away and the side focus was set at minimum distance. Same story for 3X and 4X, though the extreme position became more apparent. I found that if I left the focus at infinity, I had no issues outside up to about 6X-7X. I could readily detect a shift in the focus at 4X and above, but the DOF was deep enough to present a very good image at any distance. At 6X or so, the side focus really helped cleaning up the image to what I call "F-class quality" but it did not require much movement of the side focus knob as you would expect. At 8X and above, I could easily clean it up to "FCQ" with a small twist and I was glad to have the side focus.
Moral of the story with the March 1-10X24 (and I suspect many other LPVOs): for quick employment of the optics at low magnification, the side focus setting is irrelevant. If you want the broadest range for 1-5X or 6X, leave it in the middle of the range. Above 6X, where one should have more time to focus, the side focus knob is very handy for fine precision.
Rifles Only Accuracy Podcast Season 1 Episode 4 | Rifles Only Accuracy Podcast
Jacob and Dave talk with (well.....listen to) Michael from Leupold Optics drop some knowledge. Part 1 of several with Michael.
riflesonly.podbean.com 
Interesting, I ran a Leupold MRT 1.5-5 Illum in Iraq 05-06.I think it makes sense here to break down groups historically, and then it will establish some clarity.
I’ve seen the LPVO evolve ever since I remember LAV showing me the first 1.1-4x Schmidt & Bender Short Dot back in 2003-2004. I remember it having a FFP reticle, with daylight bright dot illumination. He said they had approached other optics manufacturers and gotten things back that nowhere matched what they had asked for, whereas S&B gave them exactly what they were looking for. As soon as I put my hands on it, I knew I wanted one.
If I recall, one of the main requirements was enabling shooters to get PID on TGTs where Aimpoints provided no advantages over naked eyes.
Right out of the gate, there were 2 initial groups who the LPVO concept were catering to:
Group 1: Free Float Carbines with LPVO for CQB and PID/shooting at distance with BDC for M855 and 75gr BTHP
Group 2: SR-25 7.62 NATO 16” carbines or 20” rifles with BDCs for M118LR (This is the group most commonly overlooked relevant to this discussion I think.)
Group 3:
Prior to this, the Recce and later SPR concepts had come to fruition with various optics solutions (1.25-4x, 2.5-8x36, 3-9x36, 3.5-10x40, 2.5-10x24), but this was for a dedicated light sniper/DMR system that leaned more on distance TGT PID/engagement with a Mini RDS solution getting added later for CQB for some.
As guys realized that the 18” barrel juice wasn’t worth the length/weight penalty squeeze most of the time, some important features from under and on top of the SPR hood were just absorbed into the M4A1 SOPMOD Block II, with good triggers, free float handguards, Mk.262 77gr, and a new line of optics. Some dudes started buying Short Dots and other 1.1-4x LPVOs with their own money or Team funds, even though they already had 1. Trijicon Reflex Sights and 2. TA01 ACOGs from the original SOPMOD package with 1/4 ratio of ACOG to Reflex, 3. Eotech 553s, 4. Aimpoint Comp Ms, 5. Eotech XPS-3s with flip-magnifiers, 6. Elcan Specter DR 1-4x, and 7. ACOGs with 8. Docter Optics RDS piggy backs on their property books.
Given the fact that within SOCOM units, they already had 2 different 4x ACOGs, Eotechs with magnifiers, and the Elcan Specter DR 1-4x as issued items, and still found merit in purchasing LPVOs, it makes you appreciate and look into the LPVO even more. This was sort of a Group 3 that was effectively achieving what Group 1 was doing more-or-less. I think LPVOs basically allowed Block II Carbines to serve better in the same space where SPRs did, without really losing any performance advantages of the carbine in CQM/CQB, with a little top end magnification taken away from the line-up of SPR optics, where 8x was the lowest on the Leupold MR/T options.
Group 4: Civilians and 3-Gunners realized that LPVOs were great for running close-range and intermediate stages that basically validated the LPVO concept in more clean settings on flat ranges and distance shooting stages.
As the desire for more and more top-end magnification followed the chase of more “true 1x” on the bottom end for replacing RDSs, the LPVO expanded into more of a do-all optic.
The two main types of platforms that are often overlooked are the requirements for the SPRs and SR-25s, and the way that higher top-end LPVOs started filling-in where the SPR optics had previously filled a niche.
Essentially, the modern higher magnification factor LPVOs manifesting themselves with the 1-8x and 1-10x units are a combination of multiple optics that previously performed different roles on the carbines with 1-4x, SR-25s and Recce carbines with 1.1-4x or 1-6x, and SPRs with 2.5-10x.
The Vortex Razor Gen III 1-10x is a better optic in both the low end and high end compared with an S&B Short Dot, with better reticle options and excellent bright red dot.
The Razor Gen III 1-10x is also a better light sniper/DM optic than any of the SPR scope options on their high end.
The desire for side focus doesn’t detract from the performance requirements in CQM, but just adds another option for the PID/longer range engagement realm. The modern era of high performance, 10 factor magnification LPVOs are showing that you can really have both ends of the spectrum in a compact optic. You don’t have to be pigeon-holed into a particular group because the optical engineering has allowed you to have the best of both worlds.
I wanted to have flexibility, run close and run far. At that time we had just formed up the 506th at Campbell and I hadn't been given an optic prior to deployment. While deployed I recieved an ACOG but kept my already zero'd MRT on my weapon (I still have it since I purchased it).
I was lucky enough to be given 20K of MK262 MOD 0 77grn SMK's from GRP when I was out there in Iraq.
Because pictures are worth a thousand words (and movies even more), these are for another point-of-reference:
I really appreciate the videos. In the first, he fails to mention that when he increases magnification, exit pupil shrinks and depth of field decreases. It doesn't sound to me like the parallax adjustment is his real issue, it's the super small depth of field at full magnification, and if anything, the adjustable parallax gives him a means of defeating those depth of field issues (at full mag). Imagine what he would think about taking 300 yard shots on those little targets if he didn't have adjustable parallax.
Regarding the second vid... If I can't have the ability to refine my focus on 10x, just give me the 1-6 which has a better and more rds-like 1x.
Last edited:
@Denys , silly question.
Would your optical calculators (formulas) translate accurately to rifle scopes?
Reason I am asking is because of the extra internal elements being present in rifle scopes that allow introduction of the erector/reticle components.
As ignorant as I am of optical construction, I know that even a basic rifle optic would have more lens elements and a more complicated light path compared to the elegant camera lens.
Perhaps none of that makes any difference in the end. Perhaps it does. Inquiring minds want to know.
./
Would your optical calculators (formulas) translate accurately to rifle scopes?
Reason I am asking is because of the extra internal elements being present in rifle scopes that allow introduction of the erector/reticle components.
As ignorant as I am of optical construction, I know that even a basic rifle optic would have more lens elements and a more complicated light path compared to the elegant camera lens.
Perhaps none of that makes any difference in the end. Perhaps it does. Inquiring minds want to know.
./
Terry, I'm not sure that statement about camera lenses is accurate.
A camera lens is essentially the equivalent of the objective lens portion of a riflescope with the first focal plane acting as the film or the sensor. The other two parts of the riflescope; the erector assembly and the eyepiece assembly are the added lens elements in the riflescope.
The way I was trying to use the calculators was to try to guess the focal length and the aperture of the objective lens group. In a silly attempt to equivalence the two, I figured the bottom mag (1X) was what the focal length of the objective was providing. You should remember that the magnification of a riflescope is calculated by dividing the focal length of the objective by the focal length of the eyepiece giving the minimum magnification, then times the erector ratio for the maximum mag.
With an LPVO, we are talking about a 1X mag, the equivalent in a 35mm sensor is 50mm lens. But the "sensor" size is really the ID of the main tube. Anyway, I used 50mm as the 35mm equivalent because that's what I grew up with and tried to figure out what the aperture was, I looked at f/5.6 and f/8 as possibilities. And then my head really started throbbing....
The numbers I was getting showed a WIDE DOF at various hyperfocal distances. So I grabbed the 1-10X24 and started checking out the numbers and that's when I wrote up my post above. The SWAG numbers were trending towards what I was seeing.
I'm still thinking about figuring out a hyperfocal calculator for a riflescope but the throbbing pain in my head has to end first.
Thanks for the reply.
Based on your statement above, I'm going to believe the short answer is pretty much Yes the calculator will fairly closely model a rifle scope.
This day has my brain fried enough that you might as well have replied in Klingon. I will have to go back and re-read the balance of your reply after my day winds down later tonight.
Thanks again.
./
"Zoshkin"? Now, I am hurt... but there is a good chance I will survive this grave insult to the spelling of my last name. I will point out that in the 30 years I've lived in this country, this is the first time my name was misspelled in this way. I seriously thought I had seen them all.
Indeed getting a large objective with true 1x on the low end is very difficult without the scope becoming absolutely enormous. The problem is with the focal length of the objective lens. It needs to be fairly short to have a compact scope with 1x on the low end.
The largest objectives with low power and high magnification ratio out there are March and Leica that all have scopes going down to 1.5x and maintaining a 42mm objective with top end magnification of 10x or higher. With lower erector ratios this is clearly easier.
Generally, here is the video where I try to explain this:
ILya
The formula is generally accurate, but it does not take into account the size of the eye pupil. It is not infinitely small.
Overall, you are correct in that the side-focus on an LPVO is more useful from the standpoint of getting the image focused than parallax elimination, although sometimes they go hand in hand.
ILya
Interesting that you equate the 50mm with a 35mm sensor to a 1X.
This is a really nice discussion. There is a lot of information here, so forgive me if I missed something. Here are few general comments.
-For most applications, there is no need to have side focus on an LPVO. However, with higher erector ratios, modern LPVOs have short objective focal lengths and comparatively shallower depths of field. However, with higher top end magnifications they are pushed into broader distance ranges, so side focus can be helpful. I have spent a lot of time with March' Shorty 1-10x24 and I only used the side focus for two situations: dry practice indoors and longer distance shooting (beyond 700 yards or so) when I wanted better focus on the target.
-My primary LPVO is Vortex Razor Gen3 1-10x24. It has more generous depth of field than the shorter March, but I still ran out of depth of field at some point. As a result, I had Vortex set it up with a 300yard parallax setting. It makes close distance focus on 10x suboptimal, but really helps at longer ranges. Since at closer distances, I usually have it on lower magnifications, it works great for me.
-The concept of hyperfocal distance only applies when the objective lens of a riflescope is focused at hyperfocal distance. None of them are, so it is not really applicable here. On top of it, defining the circle of confusion for a riflescope gets really tricky. I made some empirical measurements and, purely by accident of course, my Gen3 Razor is now set very close to the hyperfocal distance of its objective lens. Since March 1-10x24 that Denys has does come with sidefocus, he can easily figure out what the hyperfocal distance of that objective is, and back calculate the rest of it. I do not think I am supposed to disclose what the focal length of the Shorty objective is, but he can ask March.
As far as the original question goes, it is really a matter of two questions:
1) do I need side focus on an LPVO?
2) if my LPVO has side focus, is there a downside to that?
The answer to the first question is that for most applications it is not necessary, but there are use cases where it is helpful (see my firs point above).
The answer to the second question is that if we are talking about a high quality scope, there isn't much downside. If it is a budget scope of some sort, it is always a matter of adding a little more complexity while keeping the price low. I do like the idea of a locking parallax turret on an LPVO. Maybe March should do that on the next Shorty iteration.
The way I use LPVOs, they sit on low magnification and on 1x the depth of field is so generous that even if the side focus settings seems to have been bumped off somehow it does not slow me down until I am dialing the magnification up. When I was testing the 1-10x24 Shorty, I mostly kept the sidefocus around 150-200 yards setting and did not touch it until I specifically needed it.
ILya
-For most applications, there is no need to have side focus on an LPVO. However, with higher erector ratios, modern LPVOs have short objective focal lengths and comparatively shallower depths of field. However, with higher top end magnifications they are pushed into broader distance ranges, so side focus can be helpful. I have spent a lot of time with March' Shorty 1-10x24 and I only used the side focus for two situations: dry practice indoors and longer distance shooting (beyond 700 yards or so) when I wanted better focus on the target.
-My primary LPVO is Vortex Razor Gen3 1-10x24. It has more generous depth of field than the shorter March, but I still ran out of depth of field at some point. As a result, I had Vortex set it up with a 300yard parallax setting. It makes close distance focus on 10x suboptimal, but really helps at longer ranges. Since at closer distances, I usually have it on lower magnifications, it works great for me.
-The concept of hyperfocal distance only applies when the objective lens of a riflescope is focused at hyperfocal distance. None of them are, so it is not really applicable here. On top of it, defining the circle of confusion for a riflescope gets really tricky. I made some empirical measurements and, purely by accident of course, my Gen3 Razor is now set very close to the hyperfocal distance of its objective lens. Since March 1-10x24 that Denys has does come with sidefocus, he can easily figure out what the hyperfocal distance of that objective is, and back calculate the rest of it. I do not think I am supposed to disclose what the focal length of the Shorty objective is, but he can ask March.
As far as the original question goes, it is really a matter of two questions:
1) do I need side focus on an LPVO?
2) if my LPVO has side focus, is there a downside to that?
The answer to the first question is that for most applications it is not necessary, but there are use cases where it is helpful (see my firs point above).
The answer to the second question is that if we are talking about a high quality scope, there isn't much downside. If it is a budget scope of some sort, it is always a matter of adding a little more complexity while keeping the price low. I do like the idea of a locking parallax turret on an LPVO. Maybe March should do that on the next Shorty iteration.
The way I use LPVOs, they sit on low magnification and on 1x the depth of field is so generous that even if the side focus settings seems to have been bumped off somehow it does not slow me down until I am dialing the magnification up. When I was testing the 1-10x24 Shorty, I mostly kept the sidefocus around 150-200 yards setting and did not touch it until I specifically needed it.
ILya
Last edited:
I might have misunderstood what he wrote.
In a 35mm camera, what we call full-frame these days, the 35mmm (24mmX36mm) that I had with me at all times since the early 1970s, the standard lens (a term you don't hear much anymore) was about 50-55mm. That was a 1X lens.
And this is where I get in trouble.Rifles Only Accuracy Podcast Season 1 Episode 4 | Rifles Only Accuracy Podcast
Jacob and Dave talk with (well.....listen to) Michael from Leupold Optics drop some knowledge. Part 1 of several with Michael.
I had to check the date of the podcast to make sure that it was not recorded on April 1. I have no clue what he's talking about and the word "hyperfocal" is not found anywhere on the Leupold website. So I must have misunderstood something.
It's been nice knowing you guys.
I did state repeatedly that I was trying to make the hyperfocal calculators (which know nothing of riflescopes) come up with some semblance of result for these accursed riflescopes. I'm a long-time photographer and will default back to what I know best and try to make it work for a riflescope. The concepts are the same, I just use numbers that I'm familiar with. I did specify this was all "back of the envelope" crap, but it seems to work.
Thank you @koshkin for stopping in and sharing your input.
This must be what nerd kids at a sci-fi convention feel like if Harrison Ford stopped to hang out with them!
./
This must be what nerd kids at a sci-fi convention feel like if Harrison Ford stopped to hang out with them!
./
ILya, I apologize. My Vulcan keyboard has the Zark and the Kift characters next to each other and my Vulcan/English/French dictionary do not have your name memorized. Up to now.
What are you implying here?
Do not dare think that you have been out of line.
This thread was meant for discussion, debate and learning. If you or I learn anything here or change our beliefs on something we previously thought to be true then it is a win for we have grown.
Your perspectives and input are appreciated.
./
Nothing negative.
I view Koshkin as the resident brainiac expert on rifle scope specifications, comparisons and technical abilities. . . . . . at least compared to my redneck ass. I thought it was a positive addition for him to take time to post in the thread and I was feebly attempting to parallel the visit to something else.
I F'ing hate the absence of context in this type communication.
Carry on.
./
Dammit. I thought that I had the Vulcans and the Klingons add the correct spelling to the dictionary a long time ago...
ILya
Sorry, I must have missed it. I must have been sober
Similar threads
