Merlin NV unit [Archive]

mildot

27-10-2006, 10:01 PM

Well i have been using the Merlin unit with my Leupy 6-20x50 LRT varmint ret scope and ive not been happy with it. You just cant seem to get a decent view of the reticle or site picture. You cant see the finer details of a rabbit or a bunch of leaves! all you see is the silhouete. It is the same with my Burris Black Diamond 6-24x50 ballistic mildot scope.

So i bought a Swat 4-16x56 scope (as the guys seem to say that is it one of the better scopes to use) just to do a comparison with. Well the picture is far clearer and you can see the ret very well indeed. Its seems like a completly different setup. Very clear through out all ranges (provided you re-adjust the paralax) You can actualy see individual leaves at about 80-100yrds, compared to just seeing a mass of leaves. This set up as i say is far better than using it with scopes that cost 3-4 times that of the Swat scope...... The only problem with the Swat scope and the NV mount unit is that you have to remove the tightening screw of the mount unit as the Swat scope has a raised grip for the diopter adjustment which is still awkward to fit over.

Although my Leupy and Burris are fantastic scopes and have far better picture clarity than the swat scope, they just cant compare when it comes to using them with the Merlin NV unit....

P.S i now have for sale
1x Leupold VX111 6-20x50 LRT varmint reticle scope
&
1x Burris Black Diamond 6-24x50 Ballistic mildot scope
lol

pierred

30-10-2006, 06:56 PM

Hi Mate i use the same set up and agree with your coments but to avoid removing the screw if you take a sharp knife and remove the edge of the outer rim on the plasti ring you can place the ring on the scope cut edge facing the unit and slide the unit over the diopter without removing the screw, as i interchange between rifles and scopes when i remove the unit i leave the plastic ring on the scope and secure it with an elastic band so its there when i return to that gun,

HixX

31-10-2006, 04:13 PM

Have you got a model number for the Merlin NV so I can check it out please.
Thanks
John

snoj

31-10-2006, 05:48 PM

Can I have a link as well please

mildot

01-11-2006, 06:43 AM

Can i jump on the band wagon and have a link please.....OH forget that i already own one of these units... :D Very good units once you use a compatible scope! :D :D :D :D

Lazurus

25-01-2007, 11:14 AM

Link for me to please.

anthony

25-01-2007, 04:40 PM

Can I have a link as well please

Alard

25-01-2007, 05:59 PM

Thanks.

Baldie

25-01-2007, 06:24 PM

http://www.nightvisionsuppliesltd.co.uk

Dunno if it's of interest, but you can either post queries here, or send email.

There's at least 3 people here who retail the stuff and another handful willing and able to help with general NV queries. ;)

Though Clive knows very little about parallaxing dayscopes. ;) :p :D :D

cliveward

25-01-2007, 07:25 PM

Though Clive knows very little about parallaxing dayscopes. ;) :p :D :D

Errr...care to substantiate that remark? :confused:

Cheers

Clive

stillair1

25-01-2007, 09:19 PM

A pic of a merlin on the back of a swat.
http://snap33.photobox.co.uk/86885789ba4ddc2b82a42cf60142b15eb771e11eb89c67948f 924d77.jpg
Rubber band not required btw.:o :D

Baldie

26-01-2007, 03:56 AM

Errr...care to substantiate that remark? :confused:

Cheers

Clive

Will need to do a search on the airgun section later. Throat too sore to stay up any longer. But you must know the thread I'm talking about. ;) The banter one? ;) :D :D

cliveward

27-01-2007, 02:04 PM

;1612280']Will need to do a search on the airgun section later. Throat too sore to stay up any longer. But you must know the thread I'm talking about. ;) The banter one? ;) :D :D

Feeling better?

Best get searching then ;) and prove to us all exactly how I know very little about parallax error.

Cheers

Clive

Baldie

28-01-2007, 05:46 AM

Feeling better?

Not much.....

Best get searching then ;) and prove to us all exactly how I know very little about parallax error.

Cheers

Clive

;1589577']So not true..... **

Clive,

I have just had an epiphany. I reckon I know why it's called 'parallax correction'.

In a normal dayscope, you can and do focus two points to a single one, which is impossible without focussing adjustment at both ends. It also applies to NV equipment too.

First, you adjust the optical system so your eye can accurately focus on the reticule. [Or on tube in NV.] Young eyes do this easily, older eyes need the dioptre adjustment to get the ret 'in focus'.

While looking at the ret or tube, your eye is focussed at the vertical plane where the ret or tube surface forms an image. [Okay so far?]

It is physically [and mechanically] impossible for your eye to focus on two planes at the same time. The solution, is to alter the focal point of the incoming (distant) image, to where the crosshairs are, or tube image is. The action on the scope [day or night] is to refocus the image, but you are re-parallaxing the second (distant) image, to that of the first image, the ret or tube imagine. This is why it's called parallax correction. (Mate.)

The test of this, is to move your head from side to side, and the differentiation you would normally see [in your earlier definition] will have gone. Both the crosshairs and the distance image will be seen to be moving as one. In fact it's a test to confirm the image is correctly focussed.

**In conclusion, unless both images are focussed to the same point, they are not fulled parallax corrected.

If the inbound image is out of focus to the ret (or tube in NV) the image is not focussed correctly, and by default is in need of parallax correction.

I thank you. :D

Geoffrey,

FFS...lol...:D

All of what you say is true for a day scope but not for a night scope.

You of all people should know how an image intesifier works! There is no direct throughput of light. Thats why in some circles it's called an image converter tube. The image received onto the input window is then converted and projected onto the output window. Because there is no direct transmission of light then the output window becomes the 'target', not the actual distant target. And so long as the retcile is on the same focal plane as the output window of the tube then there is no parallax error.

Now if the objective optics are not focussed onto the input window of the tube it doesn't matter as there is still no parallax error as the internals of the tube (which is now the 'observer') do not move.

If you don't believe me...take one of your dedicated scopes out of stock, stick it on the test bench with a close target, adjust the objective until it's out of focus...now move your head around while looking through the ocular and you will see that the reticle stays at exactly the same place on the 'out of focus target'.

Let me know how you get on ;)

Cheers

Clive

;1592119']Clive, (mate),

Unless the ret is physically present (which it ain't) this test isn't pertinent.

The lens and tube are collimated (as you know 'cos we've discussed it). Once that is set, the tube only 'reports' what the focussing lens system provides.

You are trying to say, it's not possible to get an unfocussed image on the tube. Take one of your own systems out of stock and try to see an image at 20 yards. ;) I suspect, unless you use the 'Pro' unit with the PARALLAX correction system (which is what it does rather than how it does it) you will find the image blurred.

aka unfocussed.

Meaning it is focussed somewhere else.

Meaning there must be a parallax error.

Geoffrey,

Lol...I think we are talking about 2 different things. I'm talking about parallax and you are talking about focus ;)

You said there may be parallax problems with a dedicated scope and I'm sure you meant focus problems at short range...different things.

Parallax error in a rifle scope is seen as movement of the reticle in relation to the target when the shooter moves their head laterally off centre from the scope. This happens in day scopes but will never happen in a dedicated night scope, even if the target image appears completely out of focus! Try it.

I never claimed that a night scope can magically create a focused image on the tube at any range :D

Cheers

Clive

;1598082']
Parallax (or the correction of it) relates to getting two different planes focussed at one point. That point being the reticule. ;) This involves two focussing instruments (or three) being used.

Focus ring (AO) or sidewheel (saddle) and your eye (or eye+dioptre adjuster+lens in the ocular bell).

"Focussing" the objective lens completes the 'parallaxing' event. Having or getting the ret focussed is a forgetten action so gets ignored. But it's the other half of the parallaxing event.

A test for the target being correctly "focussed" is to move your head from side to side. If the ret following the target, the optical system is correctly parallaxed.

Does this help? ;)

Can't find the post by A.N. Other. said said the same thing but explained it differently.... [Duh.]

I've had to remove 17 smilies to get this lot posted here. Bear this in mind when reading. A lot of the levity is missing. ;)

cliveward

28-01-2007, 01:37 PM

Geoffrey,

All very interesting but can you prove to us all exactly how I know very little about parallax error.

All of my above statements are true. :confused: :confused:

Cheers

Clive

C3PO_1

28-01-2007, 02:29 PM

Guys -- with respect I think we should lay this one to rest here or take it offline. It's getting boring now.

cliveward

28-01-2007, 04:44 PM

Don't get me wrong, Geoffrey and I know each other well but even that doesn't give him or indeed anyone the right to make a statement about me that simply isn't true without being taken to task, even more so when that statement elludes to me not knowing the simplist things about the industry I'm involved with.

My company doesn't just sell night vision, we design it, manufacture it and repair it...so I think I should know my **** from my elbow where optics are concerned. ;)

Thinking you are right and knowing you are right are two separate things. ;)

Cheers

Clive

C3PO_1

28-01-2007, 05:45 PM

I don't think anyone thinks any less of you two guys: it was a fascinating debate on the other thread and clearly you both put everyone else here to shame with your expert knowledge. BTW Clive, do you replace image intensifiers for NVRS-F scopes with either Gen 1 (my current generation) or Gen 2?

cliveward

28-01-2007, 08:27 PM

Due to the very cheap cost of the unit, replacing the tube is not worthwhile as and when it fails. And unfortunately this housing is not upgradeable to Gen2.

When you get to the Gen2 level then things are much easier and worth while for either upgrading to newer/better tubes as and when they are available and repairing existing tubes with new power supplies, etc. when they fail.

Cheers

Clive

Baldie

29-01-2007, 12:13 AM

Thinking you are right and knowing you are right are two separate things. ;)

So, so true. ;)

;1617065']I've had to remove 17 smilies to get this lot posted here. Bear this in mind when reading. A lot of the levity is missing. ;)

Don't get me wrong, Geoffrey and I know each other well

And one of us still has a sense of humour. :rolleyes:

Actually, you started the "you're wrong" banter with telling me I was getting confused over parallax and focussing. I've done everything I can to explain that you DO focus either end of a scope to a point in the middle. You get two images that are not in the same place, focussed to a single point. "Parallaxed". I think you don't understand what it means, you think I don't.

Someone (in a post I can't now find despite a serious look around the board) put up an even more elaborate explanation of what I've tried to describe. On reading it I found it explained that everything I understood was correct. It followed the same test criteria I had used, and I had expected you had read it too, but maybe you hadn't. :(

Either way, it was never my intention was to upset you, and I apologise for doing that. I will stop indulging myself in the sort of relationship with you I thought we had. I will not engage in humour with you again, and will keep any comments I make strictly 'professional'.

...

cliveward

29-01-2007, 10:11 AM

Geoffrey,

I understand it all perfectly well and even gave a very succinct and correct definition of parallax error. To make it even simpler:

For parallax error to occur there have to be "2" conditions:
1. 2 objects viewed on different focal planes
2. Movement of the observer in relation to these 2 objects

Let me ask you a question:

"You are looking through a dayscope that has it's objective focus set to infinity, at a target 10 yards away. The reticle is optically centred and your eye is in perfect alignment with the centre line of the scope. Is there a parallax error?"

Hopefully pennies will be dropping by now, especially as you have read the rather technical description of parallax error in day scopes on another forum.

Cheers

Clive

Baldie

29-01-2007, 11:52 AM

dryan

29-01-2007, 12:01 PM

no need for the b 1 tchyness on the forum guys, can you not do it by pm:rolleyes:

cliveward

29-01-2007, 12:14 PM

;1619530']Define 'parallax error'.

Hopefully, pennies will be dropping.

Geoffrey,

I just did, in probably the most simple terms possible. Don't take my word for it, feel free to phone, e-mail as many optical experts as you wish...they will all concur that my description is 100% accurate.

Now how about answering 'my' question:

"You are looking through a dayscope that has it's objective focus set to infinity, at a target 10 yards away. The reticle is optically centred and your eye is in perfect alignment with the centre line of the scope. Is there a parallax error?"

The answer is going to be a simple yes or no..ok?

When you've answered it then we can move on to getting this resolved. :D

Cheers

Clive

cliveward

29-01-2007, 12:16 PM

no need for the b 1 tchyness on the forum guys, can you not do it by pm:rolleyes:

Nope, cause it's funnier here. :p

Cheers

Clive

dryan

29-01-2007, 12:20 PM

ok, by the way whats objective?:D

cliveward

29-01-2007, 12:25 PM

ok, by the way whats objective?:D

Dryan,

The "objective" lens is the lens assembly that receives the first light rays from the "object" being observed. Or in simple terms the one nearest the loud end. :D

Cheers

Clive

Baldie

29-01-2007, 12:26 PM

Pennies not dropping? Please read this:

PARALLAX ERROR - Parallax error is when changing positions of your eye will change the point of aim of your scope. The error is related to the distance the target is from you. Most sporting rifle scopes are set to be Parallax Error-Free at 100 yards. That is, when aiming through your scope at a target 100 yards away, the point of aim stays the same regardless of the position of your eye.
TEST FOR PARALLAX ERROR - It’s pretty simple (and enlightening!) to test your scope for parallax error. Position your scope or scoped firearm in sandbags so that it is aiming at a 100 yard target. Now, without touching the gun or the scope, move your head from side to side while looking through the scope. If the crosshair moves around on the target, you’re seeing parallax error at that distance. How much error depends on how much movement. I’ve seen some scopes where the movement was 4-6inches! To find the distance where your scope is parallax error-free, do this experiment at 25, 50, 75, 100, and 125 yards. The distance where it is error free will also be the distance at which you shoot most accurately.
PARALLAX ADJUSTABLE SCOPES - Scopes with an “adjustable objective” (AO) allow you to set the distance at which they are parallax error-free. These scopes are also designated as Parallax Adjustable (PA), Side Focusing (SF), etc. It's misleading to call this feature "focusing" because its really parallax correction. Its also important to note that the distance markings on the parallax adjustment are quite often NOT ACCURATE. This is partly due to the scope user's own eye optics, but also due to changes within the scope from one magnification setting to the next. In fact, some high end scope companies have addressed this by not putting specific distances on the parallax adjustment. Instead, they say use the test (above) to find the point of zero parallax error for each distance yourself. Use a silver or white paint pen to mark the positions. When all other things are equal, adjustable parallax can make even a cheap scope a bargain in the ability to dial out parallax error when aiming.

Take from >> here (http://www.eabco.com/Reports/report01.html) <<

Getting back to my original comments......

I said your budget NV was not parallax corrected for sub 27 yards (ish). The article partially quoted above suggests my understanding is correct. I've spent years around scopes and camera equipments [25+] and this understanding and the general terminology used around day scopes with regard to "re-parallaxing" etc (usually for closer distances,) has been learnt from this.

I have at least as much input to scope design as you do.:rolleyes: In fact the scope on my .223 is singularly unique, having been assembled to my requirements.

Your original point was that the scope wouldn't FOCUS down below 25 yards. Re-read the highlighted text above. You'll find that me, and the rest of the world understand this issue differently to how you see it.

I'm not going to discuss this any further. We have to agree to disagree. You are allowed to continue living in your 'bubble' if you want to. :D

cliveward

29-01-2007, 01:10 PM

Great, now we both understand that for parallax error to occur there has to be objects on different focal planes AND movement of the observer. Of course I fully understand that if both objects are on the same focal plane there will be no parallax error even with movement of the observer.

And it's also great that we now seem to agree that (as I had stated previously) parallax in terms of a rifle scope is movement of the reticle in relation to the target when the shooter moves their eye position axially.

No I have never claimed that our night vision rifle scopes were not parallax adjustable......they dont need to be! They are either fixed focus or adjustable focus.

You stated wrongly that there would be a parallax error in the scope...I said there wouldn't. I will again try and explain why.

Hopefully we can all learn something.

A night vision rifle scope can be analagised into 3 things and anyone can try this at home :D

Digital video camera/webcam = Objective lens and input of image intensifier
TV or PC monitor = Output window of tube
Overhead transparency with a cross drawn on it in marker pen = Reticle

Now turn your camera on and you will see an image on your tv screen, adjust the camera so that the image on the screen is out of focus (according to Geoffrey this should make you ripe for parallax error). Now stick the transparency with the reticle onto the tv screen.

Where parallax is concerned the 2 objects you are viewing are the tv screen and the reticle...ok so far everyone?

Now the test for parallax error is to move your observation position in relation to the screen and reticle....ok look at the tv and walk around the room, look at the tv from the jauntiest angle you can muster...does the reticle move in relation to the target? Of course it doesn't!

So therefore with night vision rifle scopes you may or may not be able to adjust the 'focus', depending on the model and design but you (unless the scope is faulty and the reticle is not focused on the same plane as the output of the tube) will never ever, ever experience parallax error!

So to sum up scopes with twiddly focus bits come in these flavours:

Day scopes have adjustment of focus to correct parallax error and night scopes have solely an adjustment of focus.

Cheers

Clive

Marko

29-01-2007, 01:39 PM

Another thread I am learning on thanks to you guys.

However, my impression was that you seemed to have known each other and gotten on and now seem to be peeved at the other which seems a dashed shame? Have I got it wrong?

I am sure you both mean the same thing, it seemed like it when I was reading the thread.

Hope you identify whatever clarification you guys need so that you do not feel animosity towards one another.

Like I said, it was informative but hopefully not at the risk of your mutual respect.

All the best

Marko

cliveward

29-01-2007, 01:45 PM

Marko,

Lol don't panic...no feelings getting hurt this end and I'm sure Geoffreys the same. :D

I'm just having a bit of a laugh with Geoffrey as whenever I say something and mean another and someone pulls me up for it I'll laugh at myself and say oops I was wrong. Lol Geoffrey doesn't seem able to do this, and not just on this subject either ;)

So yes I am goading him a bit as most people will do to wind up their mates, but also so that people can hopefully learn something :)

Cheers

Clive

Marko

29-01-2007, 01:51 PM

Baldie

29-01-2007, 02:20 PM

Now turn your camera on and you will see an image on your tv screen, adjust the camera so that the image on the screen is out of focus (according to Geoffrey this should make you ripe for parallax error). Now stick the transparency with the reticle onto the tv screen.

PARALLAX ADJUSTABLE SCOPES - Scopes with an “adjustable objective” (AO) allow you to set the distance at which they are parallax error-free. These scopes are also designated as Parallax Adjustable (PA), Side Focusing (SF), etc. It's misleading to call this feature "focusing" because its really parallax correction.

:rolleyes:

The 'test' for parallax error has never been contended, except to say that it's not a pertinent test in an NV scope because the tube is not transparent. You can't observe the distant object directly through the tube.

Despite this, there is no known nonclemature differences I'm aware of that singularly describe NV scopes in deference to normal dayscopes.

Mind you, I don't have access to 'bubble-world'. :D

I have never heard/read of any optics being 'focussed' from 27 yards to infinity? I believe that might be because it would mean saying "this optic is focussed at 27 yards, and 28 and 29 and 30 and 31 and .... " Normally this would be described as 'parallaxed from 27 yards to infinity'. [aka parallax corrected from x to y.]

Call it 'focussing' if you want. But me and the rest of the world will continue to call it parallax correction. ;) :D

Hope the weather is better in the bubble than we are having. It's dry but overcast out here. :(

We don't agree, and that's an end to it. I must go now as I've got to photograph some NV equipment for our advertising campaign. ;)

...

dryan

29-01-2007, 02:30 PM

ok,

im looking at the merlin 1 add on system, used with a deben max pro with filter.

I have 2 options of scope:

hawke night eye as below sig

simmons as below sig

Im wondering if due to the illuminated cross hair that the add on wont fit.

Both scopes non PA

Do I have to buy another scope?

Will these scopes be good enough for use with the merlin unit.

I assume I just need the short eye relief option (for rapid ).

cliveward

29-01-2007, 02:33 PM

Geoffrey,

"The 'test' for parallax error has never been contended, except to say that it's not a pertinent test in an NV scope because the tube is not transparent."

Why isn't it? Either a scope has parallax error or it doesn't. You can't discount the accepted test for parallax error as we know it, in a night vision rifle scope...just because it proves you wrong??????

"You can't observe the distant object directly through the tube."

Tadah! Exacly! And as the tube doesn't move around inside the housing then there will never be any parallax error in a night scope as we both agree that for parallax error to occur there has to be movement.

Now has anyone thought about or even tried my camera/tv/reticle anaolgy? Does it make sense?

Cheers

Clive

Recurve

29-01-2007, 02:43 PM

Baldie

29-01-2007, 02:47 PM

ok,

im looking at the merlin 1 add on system, used with a deben max pro with filter.

I have 2 options of scope:

hawke night eye as below sig

The Merlin will go on this, as there is a round area between the battery housing and your eye, where the adapter can be secured. On the down side, this scope isn't going to produce a light and large image.

simmons as below sig

Again, you'r enot going to get the most from the system with this scope because [IIRC] it doesn't parallax correct. Or in Clives' understanding, doesn't have a focus correction system. ;) :D

Im wondering if due to the illuminated cross hair that the add on wont fit.

As above. I think there is room. Certainly I've used the system on IR's scopes. [Merlin 4-14x56IR for example.]

Both scopes non PA

Do I have to buy another scope?

You'd get more out of the system with 'better suited' scopes.

Will these scopes be good enough for use with the merlin unit.

I assume I just need the short eye relief option (for rapid ).

For use on the Rapid, you would be better off buying the short-eye-relief model. ;) There is a 'package' price available where you can buy NV system plus 30mm tubed 3-12x44 sidewheel focus scope for not much money. Again I'll PM you. ;) All you will need is the new mounts for the scope. :)

...

Baldie

29-01-2007, 02:50 PM

The term parallax error has always troubled me until this thread came up. I now understand it.

Good.

You two can talk about 'focus correctable' scopes between yourselves then, and exclude the rest of us. ;) :D

"Parallax correction" is getting images at two distances focussed together on the same plane. In terms you will understand, a focussed image on a tube, where a crosshair has been 'painted' provides you (YOUR EYE) with a singularly focussed image. You don't see the two images at different distances, because your eye isn't focussable at two distances at the same time, it can only focus on one point.

When I look through any NV scope, I get to focus my eye on the tube inside by using a correcting lens next to my eye. I focus the image to my eye at "X" point in the scope. [Younger eyes can do this without help, but their eye still focusses to "X" point.]

The focussing system, on either dayscope or NV bring an image to the tube which it replicates as honestly as it can. The image falling on the tube is either focussed or it isn't. If it isn't (mindful we are talking about a weaponsight with an internal reticule, not a telescope that has the "X" point inside the viewers eye-ball) the image is NOT parallaxed to the place where the reticule is. The two images [ret and distance sub 27 yards] are not parallax corrected to each other.

YES it's true the image is not focussed, but not focussed to what? Not focussed to the ret, which is one half of the 'parallax' requirement.

It's why I and the company who went to a lot of time and trouble to write the article quoted above, tried (so far unsuccessfully) to (correctly) explain the difference in understanding 'focus' and 'parallax' in terms of weaponscopes.

...

cliveward

29-01-2007, 03:18 PM

Geoffrey,

"Parallax correction" is getting images at two distances focussed together on the same plane. In terms you will understand, a focussed image on a tube, where a crosshair has been 'painted' provides you (YOUR EYE) with a singularly focussed image."

Nooooooo! The reticle and the output window are the 2 objects being viewed!

"The focussing system, on either dayscope or NV bring an image to the tube which it replicates as honestly as it can. The image falling on the tube is either focussed or it isn't."

Yes! It "indirectly" transfers the image received at the input of the tube to the output in focus or otherwise. Just like in my camera/tv/plastic sheet analogy.

"If it isn't (mindful we are talking about a weaponsight with an internal reticule, not a telescope that has the "X" point inside the viewers eye-ball) the image is NOT parallaxed to the place where the reticule is. The two images [ret and distance sub 27 yards] are not parallax corrected to each other."

Noooooo! They are free of parallax error as the reticle is always on the same focal plane as the output of the tube! Just like the tv with the plastic sheet on it. The output window of the tube will display the 'out of focus' image from the objective lens but it will NOT have a parallax error!

I think everyone else can see this plainly. :confused: :confused: :confused: :D

Cheers

Clive

cliveward

29-01-2007, 03:21 PM

The term parallax error has always troubled me until this thread came up. I now understand it. I have a reasonable grounding in my knowledge of optics, and from the discussion thus far I would have to agree with Clive that a NV scope may well be out of focus, but it can't (unless manufactured incorrectly) suffer from parallax error which is very definitely a different thing.

The discussion has been enlightening, so thank you both.

Recurve,

No problem at all. I think comparing day scopes to night scopes has really helped us all (well most of us) to understand the differences between parallax error and focus.

Cheers

Clive

Baldie

29-01-2007, 05:33 PM

Noooooo! They are free of parallax error as the reticle is always on the same focal plane as the output of the tube!

There can be no parallax error here between tube and ret because as you rightly say, they are on the same plane. It's IMPOSSIBLE for there to be 'parallax error' here, which is why I asked you what you thought parallax error was. This isn't it.

Just like the tv with the plastic sheet on it. The output window of the tube will display the 'out of focus' image from the objective lens but it will NOT have a parallax error!

I think everyone else can see this plainly. :confused: :confused: :confused: :D

Cheers

Clive

:D :D :D :rolleyes:

Please yourself.

You are welcome to call it out of focus if you want. :rolleyes:

The rest of us will continue to call it "parallax error".

In a telescope, and unfocussed image is just as you say, an unfocussed image. But in a weaponscope, and unfocussed image (to the reticule plane) is an un-parallaxed image. The action of producing a focussed image at the same point the reticule is focussed to your eye, is the action of "parallaxing".

You just can't grasp it, can you?

And it's not just my words you can't grasp, it's everyone else who knows this stuff. Like the author of the article I linked earlier. [A company web site BTW.]

When your NV tube produces a sharp image to the same plane at the ret, it's said to be parallaxed. Until you have that, you don't just have an unfocussed image, you have an unparallaxed image. Because the sight image has not been correctly focussed to the same plane at the ret.

Point "X" = imaginary line drawn though the weapon site or NV scope where the reticule is found. In a dayscope this will be the place where a thin wire is placed (or etched onto glass).

On NV this will be where a tube has a 'painted' reticule on the surface of the tube.

The crosshair (say) that your eye focusses on, is the point to which I am calling Point "X".

Focussed image brought to Point X, at X, is a parallaxed image.

Unfocussed image brought to point X at X, is an image not parallax corrected.

I'll say it again, an unfocussed image is just that outside of a weaponscope. But an unfocussed image at the ret [Point X] in a weaponscope is an unparallaxed image because it's not corrected to the ret. [Not focussed to the ret.]

So, NV or dayscope doesn't really matter. An unfocussed sight image on the same plane as the reticule [Point X] is an unparallaxed image.

Which is what I've been trying to explain to you, but you are insistent there is no parallax error between [NV] tube surface and the reticule painted on it. Seems you gave been having a discussion with yourself, as this isn't the issue I've been [plainly] talking about.

[As an interesting aside, it's possible to defocus the ret, and see a focussed image through a dayscope. In Clives terms, this would be parallaxed <image in focus> but would fail the head moving side to side test.]

Feel free to have the last word.

"I see what you're saying at last .... " would be a good start. ;)

...

cliveward

29-01-2007, 05:56 PM

Jesus wept :D

"When your NV tube produces a sharp image to the same plane at the ret, it's said to be parallaxed. Until you have that, you don't just have an unfocussed image, you have an unparallaxed image. Because the sight image has not been correctly focussed to the same plane at the ret."

In a correctly manufactured NV scope the reticle is always on the same plane as the output of the tube...so it's parallax error free!

"Which is what I've been trying to explain to you, but you are insistent there is no parallax error between [NV] tube surface and the reticule painted on it. Seems you gave been having a discussion with yourself, as this isn't the issue I've been [plainly] talking about."

Right so you agree that the reticle and output of the tube are parallax free. Hurrah!

Now we're getting somewhere.

Now bearing in mind for parallax error to occur there has to be 2 points on different focal planes AND movement. The only bits left of the scope that you claim could have parallax error, if the incoming image is out of focus, are the objective and input of the tube. SO WHICH OF THESE BITS OF THE SCOPE IS MOVING LATERALLY TO CAUSE THE PARALLAX ERROR!

The answer NONE! The objective and tube dont move...they are fixed and by virtue of being stationary will not induce parallax error even if the image is completely out of focus.

I say again parallax error in a rifle scope is seen as movement of the reticle in relation to the target when the observer changes position laterally. This doesn't happen in a night vision rifle scope! Ever ever ever!

"[As an interesting aside, it's possible to defocus the ret, and see a focussed image through a dayscope. In Clives terms, this would be parallaxed <image in focus> but would fail the head moving side to side test.]"

Of course it wouldn't! If the reticle and target are on separate focal planes and there is MOVEMENT then there will be parallax error.

MOVEMENT MOVEMENT MOVEMENT! :D

Oh sweet Jesus! :D :D :D

It can't surely just be only myself and Recurve that understand how there can be no parallax error in a night vision rifle scope and through this wisdom, truly understand how parallax error occurs!

Cheers

Clive

Recurve

29-01-2007, 06:28 PM

cliveward

29-01-2007, 09:52 PM

Yep you got it. :D

Anyone else?

Cheers

Clive

Baldie

30-01-2007, 12:42 PM

What I understand now is that the NV system will always be parallax free, as EVERYTHING that is viewed through the scope is viewed on the same focal plane (the image produced by the intensifier tube and the reticle).

If the intensifier tube is presented with an out of focus image, then that is what the viewer will get, but, due to the out of focus image being viewed on the same focal plane as the reticle, it will by definition be free of parallax.

In a day scope, an out of focus image will, now by definition, be focused on a different focal plane to that of the reticle. We correct this aberation by bringing the image to focus on the same focal plane as the reticle and hence 'correct the parallax.

Gottit (I think)

You is obviously either a double act (which I think you are) or Clive with a second logon identity. :rolleyes:

If an image on the reticule plane isn't in focus AT THE IMAGE plane, it's not parallaxed.

[The medium that get it there isn't a consideration.]

Do you get THAT?

This is like teaching children how to add up.

You take 2 apples and 2 pears. You have 4 pieces of fruit.

You take 2 bananas and 2 oranges. You have 4 pieces of fruit.

But .......

If you take 3 bananas and 2 oranges, yes you have 3 bananas, but you don't have 4 pieces of fruit. [Despite what you two think.] **

Any out of focus image, produced by any medium, if it isn't focussed at the same plane as the reticule, it isn't parallaxed. Because .......

A sight image focuses at the reticule plane, with a reticule (focussed) on that plane = a parallaxed corrected sight image. Anything else has parallax error. Except in Clives Bubble, where his understanding of physics and scope terminology has its own rules..... :rolleyes:

** Translation.

2 apples = Focussed image on reticule plane.
2 pears = Ret correctly focussed to sight of viewer.
4 pieces of fruit = Correctly parallaxed sight image.

2 bananas = Image collimated to be focussed on reticule plane (image tube).
2 oranges = Painted ret correctly focussed to sight of viewer.
4 pieces of fruit = Correctly parallaxed sight image.

3 bananas = Image collimated to be unfocussed on reticule plane (image tube).

...

Recurve

30-01-2007, 12:53 PM

Nope, no double act and no dual identity, sorry to burst your bubble :D

As Clive has pointed out, any sighting device that has not had the parallax corrected will most certainly exhibit the characteristic that movement of the eye in the lateral plane will produce a movement of the reticle in relation to the object being viewed.

There are NO circumstances (other than poor manufacture) under which a night vision sight can exhibit this peculiarity, by virtue of the viewing system.

Quite simply, lack of focus, and parallax error are not now, and never will be the same thing. Consider for a moment a plain circular target being viewed through a conventional day scope which has been mounted and zeroed at the appropriate distance on a rifle. Let us now place the image out of focus to the viewer. If the viewer now sights at the target but with his eye moved in the lateral plane off the optical axis of the scope, any centrally aimed shots that he takes at the target will NOT hit the centre of the target. That is the result of parallax error. Make the same test with a NV scope, and no matter how much the eye is displaced from the optical centre of the scope, the shots will be aimed true and will hit the centre of the target. A NV scope cannot display parallax error. If you can explain why these circumstances exist otherwise then I will be happy to hear it.

I am quite happy to accept that this is a subject on which we may have to agree to differ, although this would largely seem to revolve around semantics and the differing understanding that the two groups of parties have of the concept of parallax. I am however rather saddened that you have felt the need to resort to trying to treat others as if they were children just because they don't agree with your viewpoint.

Phil (not AKA Clive)

Marko

30-01-2007, 12:56 PM

Marvellous, except this has all gone completely over my head!!

I look forward to having a good read tomorrow lunchtime.

Marko:)

cliveward

30-01-2007, 02:26 PM

Geoffrey,

If you won't take my word for it, how about this guys?

http://www.nightvisiononline.com/fdisplay2005.htm?action=display&num=1050016053

Quite a long, but informative article by IIRC one of the USA's experts in the field.

But here's a few quotes regarding parallax error in a dedicated night vision rifle scope from the above post for the casual readers who can't be bothered to trawl through the whole thing:

"it cannot exhibit a parralax offset with eye position"

"there is no possible parallax shift"

"Neither the objetive lens focus which adjusts the image of the target on the photocathode or the eyepiece adjustment which corrects for the individular users eye will affect the parallax adjustment"

"Unlike an optical riflesscope the parallax adjsutment is not a fucntion of target distance"

Well? Is he wrong too then?

Oh and it's not me in disguise. This was written on 8 December last year. Even though as you claim I must be able to break the laws of physics...the secret of time travel still elludes me ;)

Cheers

Clive

Baldie

30-01-2007, 04:55 PM

Quite simply, lack of focus, and parallax error are not now, and never will be the same thing.

Okay. Me, these guys (http://www.eabco.com/Reports/report01.html), and the rest of the world are talking out of our backsides. ;) :D

No probs. :D

I am quite happy to accept that this is a subject on which we may have to agree to differ, although this would largely seem to revolve around semantics and the differing understanding that the two groups of parties have of the concept of parallax.

The one single thing we don't agree on, is that an unfocussed image is not correctly parallaxed. That ONE thing. You go from admitting to being "unsure" to being completely convinced you understand fully?

I'm insistent that "parallax correction" in a weaponsight, means producing a focused image in the same plane as the reticule. It's all I'm saying, and the Company selling scopes in the US (and everything I've ever read) says the same thing.

What is a "parallax corrected image" if it isn't that?

I am however rather saddened that you have felt the need to resort to trying to treat others as if they were children just because they don't agree with your viewpoint.

While you and Clive are insistent 3+2=4 and refuse to see it any other way, I don't see I have a choice. Even counting out the bits of fruit for you, there is no admission from either of you that you have 5 bits of fruit. :D

Phil (not AKA Clive)

Clive:

The result is that if a night vision scope uses front a reticle which projects on the photocathode it cannot exhibit a parralax offset with eye position as the relationship of the reticle images and the target image are fixed on the photocathode

This isn't disputed. We are talking about the 'sight image', not the tube.:rolleyes: Nor have we ever been.

The article is basically about rets?

This has got to be the best wind up on here ever. :rolleyes: :D :D

...

Recurve

30-01-2007, 05:24 PM

Yes, I have gone from being unsure to the position I hold now, as I have had something explained to me. I had precious little understanding of the concept of what 'insecure attachment' was until a child psychologist explained it to me in a single lecture. That is the nature of learning after all, considering the information presented and decide for oneself what theories best explain the facts that we are presented with.

It is only since recently coming to shooting that I have encountered parallax error in this context. Incidentally, parallax error when being discussed in relation to viewfinder cameras has a rather different meaning, although it does have the concept of more than one focal plane involved. It is also possible to take a perfectly 'parallax corrected' photograph that is wildly out of focus ;)

I refer to my previous post and ask if you are able to explain the different way that day and night scopes would deal with the hypothetical situation I posed? Or indeed what you would describe the phenomenon as?

And bear in mind when you DO explain it, that one of the first paragraphs that YOU cite says

" PARALLAX ERROR - Parallax error is when changing positions of your eye will change the point of aim of your scope. The error is related to the distance the target is from you. Most sporting rifle scopes are set to be Parallax Error-Free at 100 yards. That is, when aiming through your scope at a target 100 yards away, the point of aim stays the same regardless of the position of your eye. "

A night vision scope will not exhibit this behaviour, as it doesn't, then by YOUR choice of definition it does not suffer from parallax error.

Your choice of source material, not mine.

cliveward

30-01-2007, 06:14 PM

Geoffrey,

"The one single thing we don't agree on, is that an unfocussed image is not correctly parallaxed."

Great...now were making progress. If there is no movement of the observer then an unfocussed image is just that...an unfocussed image! It is only when the observer moves that parallax error occurs!

This is what happens with a night scope. The unfocussed image will fall onto the input of the tube, but as the tube does not and is not able to move there is no parallax error!

Why is this so important to understand for a shooter?

Well if you truly understand what parallax error is...then you will know that if you are out shooting with your day scope set to be parallax error free at 100 yards and a target presents itself at 20 yards and you either don't have time for adjustments or your scope doesn't have any, you can take the shot and be sure of your point of impact as long as you make sure that your eye is perfectly concentric to the body of the scope and hence parallax error free.

"Yes, I have gone from being unsure to the position I hold now, as I have had something explained to me."

That's excellent and it's been worthwhile. There was a point in time when I knew nothing about optics, but I was prepared to learn. :D

I'm not trying to wind you up Geoffrey...I'm just trying to educate you.

You seem to be obsessed that parallax error is everything to do with both objects being on the same focal plane...it doesn't. Parallax error can only occur when 2 objects are viewed on different focal planes AND THERE IS MOVEMENT OF THE OBSERVER!

If there is no movement of the observer then it is 2 objects on different focal planes and there is no parallax error!

Cheers

Clive

Baldie

30-01-2007, 07:05 PM

" PARALLAX ERROR - Parallax error is when changing positions of your eye will change the point of aim of your scope. The error is related to the distance the target is from you. Most sporting rifle scopes are set to be Parallax Error-Free at 100 yards. That is, when aiming through your scope at a target 100 yards away, the point of aim stays the same regardless of the position of your eye. "

Okay.

The quoted text is a section of a much larger article. The small part quoted above, isn't a 'panacea' explanation. In fact it only indicates what 'parallax' might look like when a riflescope is tested for correction.

We are agreed (all three) that an out of focus image, is an out of focus image.

We are all agreed, that between the NV tube surface, and the 'painted' reticule there is no parallax error, because none can exist.

Neither of these two facts are disputed.

The next two issues, need clear definition.

[1]
What is meant by 'parallax error' in riflescopes. This may not be what you are [actually] looking to debate. ;) Read this (http://yarchive.net/gun/scope/parallax.html) and you'll understand what 'parallax correction' is when related to a riflescope. Forget camera's (Yashica and Mamiya 330's for example), forget telescopes, forget video equipment. We are discussing weaponscopes.

When you read the article, there is no need for you to become embroiled in the math. Just read it with an open mind.

I had several links to a really useful site on www.eatel.net but they have long since gone. :( There were excellent graphics there for all this stuff......

If you understand the article, and note it's from "Lawrence Berkeley Laboratory" you will have no option to agree what parallax correction is, with regard to (day) weaponscopes. A bit dry for some, but I found it really exciting to read. :o

[2]
Whether this terminology [parallax correction] is usable in NV riflescopes.

In some ways, it's not, especially to you and Clive because it's impossible to 'test' for it in the way you two want to. I've said from the start, this test isn't pertinent, because it's impossible to use.

But using the criteria given by the Laboratory, the focussed image must be "co-planar" with the ret to be parallax corrected, and that criteria is good (enough) for me. ;)

As long as the image is not focussed "co-planar" to the ret, there is a parallax error. Regardless to any other circumstance this term might be used, in a weaponscope/riflescope, it is given to mean the image is not correctly focussed "co-planar" to (on the same plane as) the ret.

Clive and yourself can claim this isn't pertinent. I (really) am happy you two feel it isn't pertinent to NV equipment, but I believe you are wrong, and I guess we must agree to disagree on this.

But there is no way you can debate the term "parallax correction vs focussing" with regard to (day) riflescopes. The American retailer in their article support my understanding, as does the Lawrence Berkeley Laboratory.

I would suggest it would be foolhardy for anyone to contest this issue ('1' above) any further.......

Debating whether it should be called 'parallax correction' with NV scopes, ['2' above] or 'focus correction' is a debate (bearing in mind the pertinence in '1' above and the obvious conclusion drawn) that is not only pointless, but 'fruitless'. :D :D

As before ....

Scopes with an “adjustable objective” (AO) allow you to set the distance at which they are parallax error-free. These scopes are also designated as Parallax Adjustable (PA), Side Focusing (SF), etc. It's misleading to call this feature "focusing" because its really parallax correction.

This is still pertinent to NV scopes. Again, to refute this seems a tad foolhardy to me.

While the tube is the medium that presents an image, there is a lens system in front of that which either presents a focussed image, or an unfocussed image. If an unfocussed image can't be correctly focussed to produce a 'co-planar' image to the ret, then evidently there is (in riflescope parlance) parallax error.

Either way......

I say Clives budget NV scope doesn't parallax below 27 yards.

Clive says it doesn't focus below 27 yards.

However we explain/refer it to potential buyers, they'll struggle to use it below 27 yards.....

...

Baldie

30-01-2007, 07:08 PM

You seem to be obsessed that parallax error is everything to do with both objects being on the same focal plane...it doesn't.

Cheers

Clive

I look forward to the Lawrence Berkeley Laboratory printing a retraction after receiving your advice to their error.

:p :D :D :D :D :D :D :D :D

I think I'm done here. :cool:

Recurve

30-01-2007, 08:04 PM

I simply cite again my request that you explain the expected outcomes of my proposed experiment;

1) Would a day scope with an out of focus image allow you hit the targeted centre with an eye that is not on the optical axis of the scope?

2) Would a NV scope with an out of focus image allow you to hit the targeted centre with an eye that is not on the optical axis of the scope?

(for this experiment, there must at least be sufficient clarity that we can view the target)

If the results for the day scope is NO, then congratulations, you have just demonstrated the error that is introduced by parallax.

If the result for the NV scope is YES, then there must be no error of parallax, for we are hitting what we are aiming at.

If your results are anything other than those I predict, please explain why this is the case.

Cheers, Phil.

PS

A not unreasonable definition of Parallax, the first I pulled out of a Google search;

"Parallax, or more accurately motion parallax (Greek: παραλλαγή (parallagé) = alteration) is the change of angular position of two stationary points relative to each other as seen by an observer, due to the motion of an observer. Simply put, it is the apparent shift of an object against a background due to a change in observer position."

go figure.

cliveward

30-01-2007, 08:04 PM

Oh lordy,

"We are all agreed, that between the NV tube surface, and the 'painted' reticule there is no parallax error, because none can exist."

Great because this is the only place parallax error can occur in a night scope.

"We are agreed (all three) that an out of focus image, is an out of focus image."

Great because that's all you get if the image arriving at the input window of the tube is out of focus...you cannot get a parallax error.

Geoffrey, it's you that doesn't fully understand how parallax error works or occurs.

"But using the criteria given by the Laboratory, the focussed image must be "co-planar" with the ret to be parallax corrected, and that criteria is good (enough) for me."

This is important in a day scope because you can move your eye laterally and get a parallax error if they are not on the same focal plane. But for the error to occur you have to move! This is the important bit you seem unable or now unwilling to grasp!

Right now read your following quote:

"If an unfocussed image can't be correctly focussed to produce a 'co-planar' image to the ret, then evidently there is (in riflescope parlance) parallax error."

Now read this again:

"We are all agreed, that between the NV tube surface, and the 'painted' reticule there is no parallax error, because none can exist."

Now having read your last statements...how can there ever possibly be a parallax error in a night vision rifle scope?

There can only be a focus issue....never parallax.

The stuff you quoted was very interesting...even more interesting was the contribution by Louis Boyd at the bottom...hmmmm...funny how you agree with his expert opinion on day scopes, but when he talks about night scopes (as in the thread I referenced) he's to be discounted??? :confused: :confused:

"I say Clives budget NV scope doesn't parallax below 27 yards." you are 100% wrong as there is no parallax error in a night scope, ever!

"Clive says it doesn't focus below 27 yards." Don't think I ever said those exact words. Actually the scope in question gives a useable image down to 12-15 yards. Closer than that and I would say you would start to have a focus problem.

Cheers

Clive

Baldie

30-01-2007, 11:38 PM

I'm not going anywhere with this am I? :rolleyes:

"When arguing with a fool, make sure they are not arguing with a bigger fool."

The bigger fool is me. I'm not wasting any more time discussing an optical phenomena with people who refuse to acknowledge its existence. :rolleyes:

You two carry on living in your bubble. :D

Clive, you mis-quoted me BTW.

...funny how you agree with his expert opinion on day scopes, but when he talks about night scopes (as in the thread I referenced) he's to be discounted??? :confused:

I said the article was about reticules, not parallax error. I didn't say his view was "to be discounted", I even quoted some of it IIRC. However, it seems you now refuse to accept as fact, the lesson from someone YOU used earlier as a 'learned scribe'. :rolleyes:

I have (just) spent some time tonight talking to someone who knows more about NV that any other 5 people you could nominate in this country. I have explained my view, and while he said I wasn't wrong in my understanding (so up yours Clive) he did say in NV it's generally known at 'focussing' not re-parallaxing.

So, I concede the error from the 'semantics' point of view regarding NV weaponscopes. :o :o [As Recurve suggested was the case about 14 pages ago.]

But it's a hollow victory, because you two STILL don't understand what parallax error is. :D :D

And I REALLY ain't to going to respond to either of you over this issue any further. As can be seen, I have always agreed on these:

We are agreed (all three) that an out of focus image, is an out of focus image.

We are all agreed, that between the NV tube surface, and the 'painted' reticule there is no parallax error, because none can exist.

Neither of these two facts are disputed.

<Despite Clive continuing to bleat on about it.>

The next two issues, need clear definition.

I have conceded normal 'parlance' for adjusting what is normally referred to as 'parallax error' in dayscopes, is actually referred to as "focus" control in dedicated NV scopes. :)

We still disagree on what parallax error is.

But despite a lengthy detailed opinion from a scope retailer, despite more than adequate lesson from Messrs Berkeley Labs, you two won't agree to what these people are explaining to you. By arguing the point further, I make myself to be an even bigger fool. [For wasting energy indulging you.]

...

Recurve

31-01-2007, 12:02 AM

I note that you bow out, tossing the odd barbed comment on the way, having still not addressed the problem I set you. No doubt you will say it's just because to do so and argue the point further would make a bigger fool of you. I am firmly of the belief it is because you can't offer a relevant rationale.

I am now 100% sure that I understand exactly what is meant by parallax error in a day scope, and believe it or not I agree with your analysis of this phenomenon, but as your knowledgeable friend has pointed out, an out of focus object in a NV scope isn't generally described as being subject to parallax error for the simple reason that it is not.

I feel happy that I have gone from a position of relative ignorance to a position of enlightenment, you on the other hand seem to have simply entrenched yourself further. Have you ever thought that if your arguments held water and had been well presented, that I, as one craving knowledge, would have taken your path rather than Clive's?

You carry on believing that we are in a minority of two, and that all your quoted sources prove you right. The fact that when it has been pointed out that nowhere do your sources describe parallax error in a NV scope (the emphasis there is very important), you blithely change position faster than a well trained hooker.

Still, there are none so blind as those who will not see.

Baldie

31-01-2007, 12:30 AM

cliveward

31-01-2007, 01:00 AM

Geoffrey,

Lou Boyd was not only talking about reticles but in fact the complete optical train in the scope...if you bothered to read it fully and understand.

"I have (just) spent some time tonight talking to someone who knows more about NV that any other 5 people you could nominate in this country. I have explained my view, and while he said I wasn't wrong in my understanding (so up yours Clive) he did say in NV it's generally known at 'focussing' not re-parallaxing."

I think you may have paraphrased your source there. I think he would have said you weren't wrong in your understanding of parallax error in a DAY SCOPE! Neither have I ever said you were wrong in your understanding of parallax in a DAY SCOPE. I just don't think you have full understanding.

It's generally known as focussing in a NIGHT SCOPE because that's what it is...it's not semantics! Did he manage to explain to you why it isn't called parallaxing? and did you understand why?

"But it's a hollow victory, because you two STILL don't understand what parallax error is."

How gracious :rolleyes:

Oh the search tool is a wonderful thing on the BBS. Below is a thread from May last year we both contributed to on the subject of parallax. I think to even the casual observer, this indicates that I have grasped the rudiments of parallax error in both DAY and NIGHT scopes :rolleyes: long before this discussion.

http://www.airgunbbs.com/forums/showthread.php?t=119475&highlight=clive+parallax

Or you could just flick back to post 17 on this thread, where you describe parallax error in a day scope and I agree you are correct. :eek: Then you go on to refute my claim that there is no parallax error in a night scope.:D

So I think the conclusion is that, and because of the above facts:

We both agree that we parallax a day scope.
We both now agree that we focus a night scope.

But I fear still only one of us knows why. :confused:

Cheers

Clive