Night Vision EOTECH CLIP ON THERMALS ( Full details)

[Ksracer]

What I don't understand about the pixel IN has to equal the pixel OUT theory is that it depends on where the thermal is aimed that determines what that pixel IN represents. Using that theory, once the Yoter was calibrated so the pixels in and pixels out were aligned, you should be able to swap it between rifles or have a mount that shifts without it affecting the POI. I can assure you that you can't, and the error is large. Think 6" at 100yds large. If every rifles rails were perfectly aligned, maybe it would work, but it only takes a .003" deviation over a 6" long rail to change the POI 2"@100yds. The typical Badger EFR isn't installed anywhere close to those tolerances.

I tried to draw an example. Everything is happy in the first 2 examples. The thermal is perfectly aimed at the target and CPI (center pixel in) transfers that target to the CPO (center pixel out) and the cross hair is aligned with that pixel so our POI is good. But as soon as the thermal is shifted angularly in regards to our rifle system, (remember how little it takes to cause a 2" error @100yds?) the cross hair stays reasonably aligned with the CPO, but now the CPI is aimed at some point other than the target. Now the rifle is moved until the CPI is back on the target and our POI moves with it.

I'm not trying to argue, I'm just trying to understand it. If somebody can point out the flaw in my reasoning, I'd love to discuss it.

 

[pucker]

To get these aligned & tolerances acceptable to negate any POI shift would have to be with specialized equipment. That’s a fact.

Can you describe this equipment?

I'm like Ksracer...not trying to argue, just learn. But not that long ago, facts = risley prisms in mil clip-on thermals.

Any reason the following isn't possible...?

-----------------
POI is matched to POA at factory by adjusting the screen. Done.

Sensitivity to misalignments (i.e., changing rifles) is dictated by differences in optical design.
-----------------

This would explain why the user can adjust the screen on UTC, Voodoo, Tigr, etc... (wouldn't that ruin the magic?)

LWTS-LR is known for being less sensitive to misalignment. Do we think they have better alignment equipment than Trijicon?

edit: spelling

 

[Evolution 9]

If there isn't a prism in thermals, how are 'military' clip-ons "engineered" to allow swap between rifles?

Seems to me they all (mil and commercial) adjust the screen.

Most military thermals don’t even have a menu for screen adjustment. All commercial ones do. They are absolutely and certainly not the same.

 

[pucker]

Most military thermals don’t even have a menu for screen adjustment. All commercial ones do. They are absolutely and certainly not the same.

UTC and Voodoo do.

Maybe the $80k units that you can't speak of here don't...

When you say mil units, where you drawing that line? I honestly don't know the delineation..maybe if we peasants can get = commercial?

 

[pucker]

Apologies to DRT for the derail...

These look stellar... especially the x-ELR , and appreciate you getting it imported!

 

[cantankerous]

i think the rail flex problem is overstated and exaggerated.

I've used an armasight apollo pro and the Tig.
With both units I've mounted the rifle in a tripod, fixed the scope on a distant object visible in both spectrums, dismounted the thermal and experimented with drastically moving the thermal by hand.
With both sights the crosshairs stayed on the distant power line transformer even when the transformer was moved to the edge of the thermal's field of view.

It's the true scientific method: screw around and find out.

 

[Commander Shepard]

HISS-XLR, which is arguably the best military thermal unit available, absolutely does have a screen zeroing process and it absolutely must be used when switching weapons.

I don’t have a picture of the zeroing menu option at the moment but can confirm that it exists.

 

[Evolution 9]

Very cool device!

It has already been noted that there are exceptions (mil units that require zero, but no civilian units that don’t).

All civilian units must be zeroed. Almost all Military units, past and present, don’t need to be (and/or can’t be) zeroed for clip on use.

The fact that we’re having to dig to find one exception and one other possible exception, proves the point in spades.

One of the most significant differences (the greatest difference by far in most scenarios) between commercial and military clip-ons IS, and has been, what most of us call collimation- the ability to plug and play.

How big a deal that is to each individual will be dictated by that individual’s knowledge of the difference, as well as his specific needs.

To me, it’s very important. I’ve been in situations where error was absolutely unacceptable. Other times I’ve been plinking coyotes and would be perfectly content with a bargain brand civilian thermal… but Military thermals work for both situations

 

[cantankerous]

It can definitely be a pain zeroing the screen when switching between rifles.
Even with multiple profiles it can become a hassle to remember which profile goes with which rifle.
This was a big part of my decision to swap the Tig out.

If nothing else it'll save money on overpriced ammo when zeroing!

 

[stefan73]

Very cool device!

It has already been noted that there are exceptions (mil units that require zero, but no civilian units that don’t).

All civilian units must be zeroed. Almost all Military units, past and present, don’t need to be (and/or can’t be) zeroed for clip on use.

The fact that we’re having to dig to find one exception and one other possible exception, proves the point in spades.

One of the most significant differences (the greatest difference by far in most scenarios) between commercial and military clip-ons IS, and has been, what most of us call collimation- the ability to plug and play.

How big a deal that is to each individual will be dictated by that individual’s knowledge of the difference, as well as his specific needs.

To me, it’s very important. I’ve been in situations where error was absolutely unacceptable. Other times I’ve been plinking coyotes and would be perfectly content with a bargain brand civilian thermal… but Military thermals work for both situations

The question is how does it work and is it really collimated and to what acceptable standard? Minute of a man? How does it account for variations in rails? Barrels? Mill standard items should be within a specific realm so is the optic really collimated or is it just being placed on a like item with acceptable variations in tolerances? Collimated on thermal seems strange because it wouldn't appear that you could use the same voodoo like a PVS30, 27, 26 or 24. Those use risley prisms unless I am mistaken but that wouldn't work for a digital signal that is being projected onto a screen?

I'm trying to learn. Lots of questions.

I still remember zeroing my M2A3 back in the day (not a clipon) but it sure was fun with that M242 Bushmaster and TOW's.

 

[Conqueror]

DRT and SOK said they just plopped an xELR on a 300NM rifle and made consecutive hits at 1200+ yards with no change to the scope's usual dope, which indicates far better than "minute of man" calibration.

 

[stefan73]

DRT and SOK said they just plopped an xELR on a 300NM rifle and made consecutive hits at 1200+ yards with no change to the scope's usual dope, which indicates far better than "minute of man" calibration.

The more I think about it the more it appears just compensation for optical offset of objective lens and ocular lens. There would be variation depending on proper optic alignment. How far off alignment can you get away with?

Just thinking out loud.

 

[Conqueror]

I suspect it's a combo of that and rear eyepiece design. Like, there is probably a way to design the rear lens such that it compensates for some degree of malalignment of the thermal and the day scope - like, the farther off-axis the day scope is, the more correction it would need, so the rear lens would need to consist of concentric rings of increasing correction of the light path toward center. Combine that with careful calibration as described above and you end up with a device that is strongly resistant to alignment issues, moreso than more basic units.

 

[rlsmith1]

So I've always been told with I2 equipment that is prism collimated that it doesn't matter if the unit is close or further away from the scope objective.

What I'm hearing everyone say here is that a thermal (non prism) unit would be best aligned (most forgiving setup) if set a couple inches away from the scope as opposed to as close as possible? I'm not saying extreme cases but more of a couple picatinny slots. Maybe it doesn't even make a difference

 

[Conqueror]

No I don't think so, the closer the optics are together the less distance the image has to be corrected. I have always been told to mount them as close together as possible.

 

[stefan73]

I suspect it's a combo of that and rear eyepiece design. Like, there is probably a way to design the rear lens such that it compensates for some degree of malalignment of the thermal and the day scope - like, the farther off-axis the day scope is, the more correction it would need, so the rear lens would need to consist of concentric rings of increasing correction of the light path toward center. Combine that with careful calibration as described above and you end up with a device that is strongly resistant to alignment issues, moreso than more basic units.

I totally agree, for the mill versions their stuff needs to be tight/on. Otherwise they wouldn't be getting the contract. I find this interesting and am just thinking out loud and wondering how they do it.

That makes sense of the ocular light path. I wonder how much variation in alignment they can take?



This is something I probably should mull over more while enjoying a beer.

 

[WhereNow&How]

So I've always been told with I2 equipment that is prism collimated that it doesn't matter if the unit is close or further away from the scope objective.

What I'm hearing everyone say here is that a thermal (non prism) unit would be best aligned (most forgiving setup) if set a couple inches away from the scope as opposed to as close as possible? I'm not saying extreme cases but more of a couple picatinny slots. Maybe it doesn't even make a difference

Take your thermal device. Put it in front of your day optic (via holding with hand) with display screen up reasonably close to your day optic.

Sight your day optic up on a object looking through the thermal and then move the front lens of the thermal around (off target) and see if your cross hairs do or do not stay on the object you were sighting on.

 

[jwramp]

Take your thermal device. Put it in front of your day optic (via holding with hand) with display screen up reasonably close to your day optic.

Sight your day optic up on a object looking through the thermal and then move the front lens of the thermal around (off target) and see if your cross hairs do or do not stay on the object you were sighting on.

If it's a truly 1x "unity" image being shown out the back of the eyepiece, as you point the thermal at different things, the day scope reticle should maintain aim on whatever target is in front of it. Just like sticking a toilet paper tube out at arms reach - as you tilt it around, you can still see stuff through it without issue until you angle it too far and just see cardboard.

The only time the thermal image should throw it off target is if it's not properly demagnifying to 1x at the back. If even 1.1x, just tilting it slightly off-center will throw the image off-axis.

It surprises me that once a thermal clip-on is "zeroed" or "collimated" to a given rifle setup, it wouldn't maintain correction on different rifles as long as it's not being set up real crooked. Which non-mil thermal clip-ons are being referenced as having big shifts when swapping rifles/scopes?

 

[rlsmith1]

If it's a truly 1x "unity" image being shown out the back of the eyepiece, as you point the thermal at different things, the day scope reticle should maintain aim on whatever target is in front of it. Just like sticking a toilet paper tube out at arms reach - as you tilt it around, you can still see stuff through it without issue until you angle it too far and just see cardboard.

The only time the thermal image should throw it off target is if it's not properly demagnifying to 1x at the back. If even 1.1x, just tilting it slightly off-center will throw the image off-axis.

It surprises me that once a thermal clip-on is "zeroed" or "collimated" to a given rifle setup, it wouldn't maintain correction on different rifles as long as it's not being set up real crooked. Which non-mil thermal clip-ons are being referenced as having big shifts when swapping rifles/scopes?

Had not considered true unity but I think that is exactly it. Cheaper units are close to unity but not quite while the more expensive units are meticulously designed to be as close to unity as possible

 

[Ksracer]

Take your thermal device. Put it in front of your day optic (via holding with hand) with display screen up reasonably close to your day optic.

Sight your day optic up on a object looking through the thermal and then move the front lens of the thermal around (off target) and see if your cross hairs do or do not stay on the object you were sighting on.

With the Yoter-C on a clamp-on objective mount, I can see the reticle move off target ~2" by just resting my hand on it to push a button.

If it's a truly 1x "unity" image being shown out the back of the eyepiece, as you point the thermal at different things, the day scope reticle should maintain aim on whatever target is in front of it. Just like sticking a toilet paper tube out at arms reach - as you tilt it around, you can still see stuff through it without issue until you angle it too far and just see cardboard

Some body else mentioned it, but I think the key is that light doesn't pass through a thermal like it does a toilet paper tube. The light is taken straight in the front, converted to an electrical signal, and then projected straight out the back.
It seems to me that it's more like a mirror that can "turn" the light before it gets to the day optic.

 

[jwramp]

With the Yoter-C on a clamp-on objective mount, I can see the reticle move off target ~2" by just resting my hand on it to push a button.

Does the center of the reticle keep looking at the same pixels on the screen though? Sounds more like you're deflecting the whole front third of the scope rather than offsetting the thermal from the scope.

 

[Conqueror]

Does the center of the reticle keep looking at the same pixels on the screen though? Sounds more like you're deflecting the whole front third of the scope rather than offsetting the thermal from the scope.

Agreed, we need to know what happens if you replace the thermal with an equally long sunshade and push down on it. It’s theoretically possible you are deflecting your whole objective bell.

 

[Evolution 9]

If it's a truly 1x "unity" image being shown out the back of the eyepiece, as you point the thermal at different things, the day scope reticle should maintain aim on whatever target is in front of it. Just like sticking a toilet paper tube out at arms reach - as you tilt it around, you can still see stuff through it without issue until you angle it too far and just see cardboard.

The only time the thermal image should throw it off target is if it's not properly demagnifying to 1x at the back. If even 1.1x, just tilting it slightly off-center will throw the image off-axis.

It surprises me that once a thermal clip-on is "zeroed" or "collimated" to a given rifle setup, it wouldn't maintain correction on different rifles as long as it's not being set up real crooked. Which non-mil thermal clip-ons are being referenced as having big shifts when swapping rifles/scopes?

This is clearly not the case for a few reasons:

1. Multiple manufacturers (who know how to make a clip-on better than any of us do), offer multiple zero points that they advertise as allowing the clip-on to be used on multiple rifles. This would make zero sense if the device was good to go on multiple rifles after the first calibration. In fact, it would be a terrible thing to advertise that you have to switch profiles when switching guns, if you actually didn’t have to… are they intentionally making their product seem less capable than it is?

2. If that was true, Those same manufacturers could “zero” the device at the factory for about $10 in US labor cost, and this whole issue would never have come up… and they would have saved big money on creating manuals, and customer service to help users zero their clip-on. You’re telling me that every single commercial manufacturer decided to save $10 on $4000-$6000 thermals, even though that $10 would set them apart from the competition? No chance. None at all. Obviously this route wasn’t taken because it doesn’t work that way.

3. Commercial clip-ons work by adjusting the margins to center the screen on the day scope reticle (we know this for certain). Doing this doesn’t change the screen size from 1x to not 1x or vice versa, so by definition we know that size of the image isn’t the only issue (at a bare minimum it’s size and location, up-down-left-right).

So: at a BARE MINIMUM, military clip ons have figured out how to adjust the image up-down-left-right to fit different rifles/optics without actually adjusting anything. Prism? Lense? Software?

4. We have first hand accounts from multiple users (like the one a couple posts up) who report that zeroing on one gun may get you closer on the rest of your guns, but does NOT give a true POA=POI on their other guns.

 

[Ksracer]

Does the center of the reticle keep looking at the same pixels on the screen though? Sounds more like you're deflecting the whole front third of the scope rather than offsetting the thermal from the scope.

Most of the flex happens where the Rusan mount is split to allow it to close around the bell. You can visually see it deflect. It comes right back to zero as soon as you remove your hand though.

Agreed, we need to know what happens if you replace the thermal with an equally long sunshade and push down on it. It’s theoretically possible you are deflecting your whole objective bell.

I've already ran those tests because people think using your hand on a scope to steady it on a barricade will do the same thing. I can pick the the front of the 60# scope sled up before the reticle moves any perceptible amount. I actually used a soft sided clamp and tried (carefully) to deflect it. I suppose it's possible in theory, but it's not what caused the reticle to shift on the Yoter's image.

 

[stefan73]

If it's a truly 1x "unity" image being shown out the back of the eyepiece, as you point the thermal at different things, the day scope reticle should maintain aim on whatever target is in front of it. Just like sticking a toilet paper tube out at arms reach - as you tilt it around, you can still see stuff through it without issue until you angle it too far and just see cardboard.

The only time the thermal image should throw it off target is if it's not properly demagnifying to 1x at the back. If even 1.1x, just tilting it slightly off-center will throw the image off-axis.

It surprises me that once a thermal clip-on is "zeroed" or "collimated" to a given rifle setup, it wouldn't maintain correction on different rifles as long as it's not being set up real crooked. Which non-mil thermal clip-ons are being referenced as having big shifts when swapping rifles/scopes?

Interesting. When you place the toilet paper tube farther the center hole appears smaller and lesser variances in the angle it is held at appears to be greater.

Easy way to describe this is to make a circle with your hand then place it up to your eye and look through, then move it away from your eye and look how small it looks.

Almost like looking through a scope with your eye too far back, you don't get the entire picture. I'm probably making this as clear as mud.

 

[Ksracer]

3. Commercial clip-ons work by adjusting the margins to center the screen on the day scope reticle (we know this for certain). Doing this doesn’t change the screen size from 1x to not 1x or vice versa, so by definition we know that size of the image isn’t the only issue (at a bare minimum it’s size and location, up-down-left-right).

Agreed. I posted a video elsewhere, but when you remove the viewing eyepiece and install the clip on adapter to the Yoter-C, it shrinks the screen size from a full 1024 to what appears to be 640. So 1 pixel in the front equals 1 pixel out in the rear. Shrinking it leaves black margins around the edge and you can see those margins shrink and grow as you adjust the thermals zero coordinates. If you pull up the menu and pay attention to where your reticle is on the icons, they shift also as you move the zero coordinates.

None of this relates to the Eotech units though. Perhaps it's time for a new thread?

 

[stefan73]

Agreed. I posted a video elsewhere, but when you remove the viewing eyepiece and install the clip on adapter to the Yoter-C, it shrinks the screen size from a full 1024 to what appears to be 640. So 1 pixel in the front equals 1 pixel out in the rear. Shrinking it leaves black margins around the edge and you can see those margins shrink and grow as you adjust the thermals zero coordinates. If you pull up the menu and pay attention to where your reticle is on the icons, they shift also as you move the zero coordinates.

None of this relates to the Eotech units though. Perhaps it's time for a new thread?

The "Magic" of thermal clipon collimation, zeroing. Would be a great thread.

 

[cantankerous]

This has been an interesting thread. The best I can figure is that there are different qualities of lenses to compensate for misalignment.

Even the military thermals seem to live by this rule: from what I've gleaned here even the UTC series is more sensitive to alignment than the LWTS-LR.

Evolution makes a good point (point #1), if it was just a matter of calibrating the thermal everyone would do it.

The only theory I can come up with is back end lenses quality,
However:
"In theory there's no difference between practice and theory, but in practice there is."
I'd love to hear from an engineer in this industry!

 

[Conqueror]

I feel like a lot of the UTC's POI shift (some users report minimal, others in the 0.5 to 1.5moa range) has been attributed to its non-standard height and the fact that is has a fairly small eyepiece with an oddball design compared to other competitors. I dunno if that's 100% accurate but it seems a reasonable explanation.

 

[TheHebrewHammer]

What is the ideal height for rings to perfectly align the ELR? Want to be ready to go when they start shipping @DownRangeThermal

 

[DownRangeThermal]

What is the ideal height for rings to perfectly align the ELR? Want to be ready to go when they start shipping @DownRangeThermal

1.50

 

[DownRangeThermal]

If it's a truly 1x "unity" image being shown out the back of the eyepiece, as you point the thermal at different things, the day scope reticle should maintain aim on whatever target is in front of it. Just like sticking a toilet paper tube out at arms reach - as you tilt it around, you can still see stuff through it without issue until you angle it too far and just see cardboard.

The only time the thermal image should throw it off target is if it's not properly demagnifying to 1x at the back. If even 1.1x, just tilting it slightly off-center will throw the image off-axis.

It surprises me that once a thermal clip-on is "zeroed" or "collimated" to a given rifle setup, it wouldn't maintain correction on different rifles as long as it's not being set up real crooked. Which non-mil thermal clip-ons are being referenced as having big shifts when swapping rifles/scopes?

Correct!

 

[Evolution 9]

No, I’ve already given 3 proofs that this isn’t correct.

I can make a video 4th if needed…

Proof #4

For anyone thinking this would be different with a camera instead of a drawing, of course it would. In some ways it would be better and in some ways It would be worse, because we could twist it in multiple directions (angles).

 

[Conqueror]

I made a video too which also shows why both size and position calibration must occur:



Fundamentally the iPhone is like a thermal clip-on; there's a camera up front, a screen on the back, and software with which the user/builder can adjust the size of the displayed image and the portion of the camera's view sent to the display screen.

 

[cantankerous]

I made a video too which also shows why both size and position calibration mus

 

[cantankerous]

This demonstrates what I saw with my IR defence IR Hunter in clip on mode. It was apparent the scope was looking straight into an adjustable diopter then an LCD screen.
Any pressure at all on the free float rail would give some pretty extreme POI shifts.

As per my post above the TIG and Apollo Pro (and I assume at least some other civilian clip on) have lenses to compensate for this error despite the requirement to zero the screen.


sorry for the awkward posts.
My device had a stroke in the middle of typing my reply

 

[WhereNow&How]

Any pressure at all on the free float rail would give some pretty extreme POI shifts.

Take some riser bridge mounts (length to fit your application) similar to below link and make sure that one end clamps onto the receiver portion and one end clamps on to free float rail. You will likely find that it will stiffen up the free float rail whereby you have no movement on it when you put pressure on it.

 

[DownRangeThermal]

This demonstrates what I saw with my IR defence IR Hunter in clip on mode. It was apparent the scope was looking straight into an adjustable diopter then an LCD screen.
Any pressure at all on the free float rail would give some pretty extreme POI shifts.

As per my post above the TIG and Apollo Pro (and I assume at least some other civilian clip on) have lenses to compensate for this error despite the requirement to zero the screen.


sorry for the awkward posts.
My device had a stroke in the middle of typing my reply

Not a unity device

 

[Ksracer]

Not a unity device

What's the definition of unity?

Edit.
I started a new thread if anybody would care to take this discussion over there.

 

[cantankerous]

I wasn't as clear as I should have been:
The IR Hunter was a dedicated sight with a "clip on mode" which was useless.
I sold it a couple years ago.

As for getting this thread back on ltracl, any chance of getting more pictures through these Clip IRs?

 

[JoeZ]

1.50

Also, does the mount have to be level or can I use a mount with say 20.6 moa built in?

 

[Conqueror]

You can use a canted base, the optic will be very slightly misaligned but it will still work fine.

 

[DownRangeThermal]

I wasn't as clear as I should have been:
The IR Hunter was a dedicated sight with a "clip on mode" which was useless.
I sold it a couple years ago.

As for getting this thread back on ltracl, any chance of getting more pictures through these Clip IRs?

I'll grab a bunch this week. Big LE trade show here. All will be on display.

 

[Conqueror]

We need some videos man!

 

[upSLIDEdown]

We need some videos man!

View attachment 7861511

Through something other than an LPVO. Love to see a 3-18 or 5-25 behind the big boi.

 

[earthtrekker1775]

Through something other than an LPVO. Love to see a 3-18 or 5-25 behind the big boi.

Somebody send me one for "testing" and I will post a bunch of videos of me using it in front of a 5-27

 

[cantankerous]

Through something other than an LPVO. Love to see a 3-18 or 5-25 behind the big boi.

This!

I'd love to see some pictures and videos of critters, buildings and terrain at extended ranges through higher magnifications.

 

[jwramp]

This!

I'd love to see some pictures and videos of critters, buildings and terrain at extended ranges through higher magnifications.

What would be really cool would be a rifle set to a given magnification, say 6x for example, then get video through the scope while clipping on the whole line of ClipIRs consecutively, showing what advantage you get by choosing each device - how big the step in performance is at warm targets at a given distance.

 

[cantankerous]

What would be really cool would be a rifle set to a given magnification, say 6x for example, then get video through the scope while clipping on the whole line of ClipIRs consecutively, showing what advantage you get by choosing each device - how big the step in performance is at warm targets at a given distance.

I like this idea but I'd want to see different amounts of magnification at range.
A lot of devices can look good even at medium magnification (10x) at short range.

The best way to demonstrate these thermals is to push the limits of what they're capable of.

 

[Longshot231]

Doesn’t look these clip-ons are legal in Kalifornia.