Night Vision Day optic reticle is out of focus when paired with thermal clip-on

[mikefraz]

Thermal: StingIR 640

Optic: PA SLX 1X Microprism.

My day time optic is perfectly clear to my eyes when ran individually, but the second I put my thermal in front of it on the rail, my reticle on my day scope is then out of focus when the thermal is perfectly clear. I tried the thermal in handheld and clip on mode and it doesn’t seem to make a difference image wise.

It doesn’t immediately strike me as anything wrong with my thermal, as it works just fine in handheld mode, and looks the same (but reduced in window size) in clipon mode. I adjusted the diopter on my day optic to the extreme limits in both directions and it doesn’t seem to make much of a difference. Sometimes I can manually focus my eyes to make the day scope reticle in focus, in the same way you have to adjust your eye’s focus to read words 4 inches in front of your face instead of 2 feet away, but obviously that’s not a solution. Is there something simple I’m missing?

Edit: Just to be clear, the thermal’s image is crystal clear when looking at it through my day optic, it’s just the day optic’s reticle that is out of focus.

 

[diverdon]

Does that optic have a parallax adjustment?

 

[shoots100]

I'm guessing the fixed parallax of the microprism is the issue.
I've only used a clip on in front of an lpvo with parallax adjustment and never had an issue.

SJC

 

[mikefraz]

No parallax adjustment. With that being said, I’ve seen numerous people run the StingIR and RH25 in front of 1.5x, 2x, 3x, 3.5x, and 4x ACOG’s without any issue.

 

[shoots100]

Trijicon designed the Acog to work behind a thermal, I'm guessing the engineers of the $250 microprism didn't ?

 

[mikefraz]

Trijicon designed the Acog to work behind a thermal, I'm guessing the engineers of the $250 microprism didn't ?

Fair enough. I can use another optic with the StingIR, but the microprism actually works really well as far as how much of the thermal screen fills the optic’s viewing window. Thats too bad I guess.

 

[WhereNow&How]

Trijicon designed the Acog to work behind a thermal, I'm guessing the engineers of the $250 microprism didn't ?

I run the Primary Arms Gen 1 Cyclops behind Flir Thermosights with no issues. But they do not reduce the screen size and you can move the screen around in X & Y to collimate it to the day reticle. Might be the fact that the Sting IR is reducing the screen size when it goes into clip on mode.

@mikefraz, can you adjust the screen on the Sting IR without it reducing the screen size?

 

[mikefraz]

I run the Primary Arms Gen 1 Cyclops behind Flir Thermosights with no issues. But they do not reduce the screen size and you can move the screen around in X & Y to collimate it to the day reticle. Might be the fact that the Sting IR is reducing the screen size when it goes into clip on mode.

@mikefraz, can you adjust the screen on the Sting IR without it reducing the screen size?

Yes, the screen size does reduce when I switch it into clipon mode, but that doesn’t change how my reticle looks. The reticle is out of focus to my eye regardless of what mode it’s in. The StingIR does have a diopter that I haven’t tried to adjust yet, but I was under the impression that the diopter needed to be kept at the “unity” position or the clip on mode wouldn’t work. Is that not true?

 

[WhereNow&How]

but I was under the impression that the diopter needed to be kept at the “unity” position or the clip on mode wouldn’t work. Is that not true?

Ahh, I was under the impression from your previous posts that you had adjusted the thermal diopter.

So you need to adjust the thermal diopter and day scope diopter whereby everything is good and clear. If you can turn the Sting IR Cross Hairs on while in clip-on do so and adjust them (if it allows that) to overlay your day optic reticle. Then tweak both Thermal and Day Sight Diopters until entire image is clear including both Cross Hairs. Then move your head around to see that there is not any "parallex between" the two Cross Hairs.

If you do that you should be good to go. Then the next question is the zoom on the Thermal. So if you zoom does it still hold POA/POI.

 

[WhereNow&How]

Just to be clear, I don't think overlaying the Sting IR Cross Hairs will collimate the Thermal to your Day Scope but will just tell you where you need to have your Diopters set for both the Thermal and Day Scope. Then mark both respective diopters so you know where the happy spot is when they are "running together" so to speak.

So with a Flir Thermosight (does not reduce the screen size in any way) I cut the Thermal Cross Hairs off and then move my screen around to collimate it with my Day Sight. Once you do that, then turn the Thermal Cross Hairs back on and shift them over to now overlay your Day Scope Cross Hairs via the regular boresight menu. Point of doing that is when you zoom the Thermal screen it will stay collimated with your Day Scope Cross Hairs.

Im not familiar with the Sting IR at all, this is just what works for me using Flir Thermosights with a Primary Arms Gen 1 Cyclops behind them.

 

[mikefraz]

Ahh, I was under the impression from your previous posts that you had adjusted the thermal diopter.

So you need to adjust the thermal diopter and day scope diopter whereby everything is good and clear. If you can turn the Sting IR Cross Hairs on while in clip-on do so and adjust them (if it allows that) to overlay your day optic reticle. Then tweak both Thermal and Day Sight Diopters until entire image is clear including both Cross Hairs. Then move your head around to see that there is not any "parallex between" the two Cross Hairs.

If you do that you should be good to go. Then the next question is the zoom on the Thermal. So if you zoom does it still hold POA/POI.

I understand what you’re saying. I have only adjusted the diopter on the microprism. Like I said, I was under the impression that adjusting the thermal’s diopter would cause issues when using it in clip on mode. I saw some posts in the RH25 thread mentioning that. Maybe that’s an RH25 specific issue. I’ll have to give what you said a try the next time I have some free time. Otherwise I’ll probably pick up a TA44 ACOG.

 

[WhereNow&How]

Maybe they got the DOT in the wrong spot.

 

[CoryT]

This is not making any sense. The eyepiece on the day scope is responsible for one thing, focus of the reticle to your eye. If it is set correctly, nothing you place in front of the day scope is going to change that.

What it sounds like is that you have a parallax problem, where the thermal image is on focused on the plane of the reticle and you are actually forcing your eye to look at the thermal image, which them makes the reticle seem unfocused. Try this; looking through the day scope at a nominal range target where the reticle is properly focused, set the thermal up to focus on the same target with the eyepiece set to 0 diopters. Now, while looking in the day scope, tip the thermal into place WHILE KEEPING MENTAL FOCUS ON THE RETICLE. If the reticle goes 'out of focus', it was not set correctly in the first place OR, the thermal image is well out of the plane of the reticle and you have shifted your mental focus onto it.

With no parallax adjustment on the day scope, it may not be possible to get the thermal image onto the reticle. While looking into the scope, move your head a bit and see if the reticle seems welded to the thermal image or if it seems to move in relation to it. If parallax is correctly set, the two images should be locked together and them reticle focus should be no problem.

 

[mikefraz]

This is not making any sense. The eyepiece on the day scope is responsible for one thing, focus of the reticle to your eye. If it is set correctly, nothing you place in front of the day scope is going to change that.

What it sounds like is that you have a parallax problem, where the thermal image is on focused on the plane of the reticle and you are actually forcing your eye to look at the thermal image, which them makes the reticle seem unfocused. Try this; looking through the day scope at a nominal range target where the reticle is properly focused, set the thermal up to focus on the same target with the eyepiece set to 0 diopters. Now, while looking in the day scope, tip the thermal into place WHILE KEEPING MENTAL FOCUS ON THE RETICLE. If the reticle goes 'out of focus', it was not set correctly in the first place OR, the thermal image is well out of the plane of the reticle and you have shifted your mental focus onto it.

With no parallax adjustment on the day scope, it may not be possible to get the thermal image onto the reticle. While looking into the scope, move your head a bit and see if the reticle seems welded to the thermal image or if it seems to move in relation to it. If parallax is correctly set, the two images should be locked together and them reticle focus should be no problem.

That makes sense. I’ll set up a tripod and really fine tune everything.

 

[mikefraz]

Just want to post an update. I’m happy to report that the obvious/stupid/easy fix of just adjusting the diopter on the StingIR did the trick and sharpened my reticle right up and is now focused on the same plane as the thermal image. The issue was that the diopter was turned all the way counter clockwise a full rotation. After mounting it in front of my optic, I slowly turned the diopter until everything looked crystal clear and it turns out that that “sweet spot” for me was perfectly lined up with the “unity” line. Almost like that’s where it was supposed to be from the start

Took it out behind my house where I have fields going back about 30 acres and ran it through its paces and I’m very happy with it. Hopefully this will be helpful to someone else who is having the same problem in the future.

 

[shoots100]

Good to hear you found the answer and it's a whole lot cheaper than buying an ACOG.

 

[mikefraz]

Good to hear you found the answer and it's a whole lot cheaper than buying an ACOG.

I still plan on getting the GLX Microprism once it becomes available. Teased at SHOT Show, it has better glass quality, better eye box, and overall better build quality. But if it works so well on the SLX, I can only assume that the GLX will be even better.