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Vortex Razor UHD 18x56 ?

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Old Wednesday 3rd July 2019, 03:15   #1
gonz33
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Vortex Razor UHD 18x56 ?

Having 18 power will look something dark? I have the Zeiss Conquest HD 15x56 are incredible, but I want to buy the model 18x56 for having more power, but my doubt is the darkness for having so much increase.

Jose.
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Old Wednesday 3rd July 2019, 12:54   #2
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Ryan Avery has been testing them for the past two weeks. He is very impressed.https://www.rokslide.com/forums/thre...-18x56.117494/
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Old Saturday 6th July 2019, 20:29   #3
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I spent some time this morning behind the 18's... way more than I expected. Great binos
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Old Monday 8th July 2019, 12:40   #4
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Your Conquest HD is a nice, quality binocular with a track record of good performance. I wouldn't think a 18X56 is going to do THAT much over a 15X56. Of course low light performance is going to be best with the 15X56.

If I were in the market for a 18X56, I'd probably take the hardest look at the Maven B.5. Great company and you can try one and return if you don't like it.

https://shop.mavenbuilt.com/collecti...b-5-black-gray
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Old Sunday 14th July 2019, 15:10   #5
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" I wouldn't think a 18X56 is going to do THAT much over a 15X56. Of course low light performance is going to be best with the 15X56."

A 15x56 is not necessarily going to have better low light performance than an 18x56 because the "Twilight Factor" of the 18x56 is going to be better than the 15x56. The 15x56 might be brighter because of it's bigger exit pupil but the 18x56 will resolve more detail because of the higher magnification. Here is a resolution test on Youtube where the Vortex Kaibab 18x56 out resolved the Swarovski 15x56 SLC under low light. I think the New Vortex Razor UHD's could be just marketing hype. I had several pairs of Vortex Razor HD's and several pairs of Vortex Viper HD's and I thought the Viper HD's were just as good as the Razor's. I just bought a Vortex Viper HD 12x50 and it is an excellent 12x for under $500.00. MIC but no quality problems at all. If I were you and you want an 18x56 I would buy the Vortex Kaibab 18x56. Here is a new one on Ebay for $899.00.

https://www.ebay.com/itm/Vortex-Kaib...0AAOSwRkJdJ3KL
https://www.youtube.com/watch?v=SYoU7ZSX0FQ

Last edited by [email protected] : Monday 15th July 2019 at 00:39.
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Old Sunday 14th July 2019, 18:23   #6
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Quote:
Originally Posted by chill6x6 View Post
Your Conquest HD is a nice, quality binocular with a track record of good performance. I wouldn't think a 18X56 is going to do THAT much over a 15X56. Of course low light performance is going to be best with the 15X56.

If I were in the market for a 18X56, I'd probably take the hardest look at the Maven B.5. Great company and you can try one and return if you don't like it.

https://shop.mavenbuilt.com/collecti...b-5-black-gray
The 18x56 are already sold out.

If anyone is interested there is a used one up for sale on archerytalk the seller is sticking with his 15x56.

Last edited by zzzzzz : Sunday 14th July 2019 at 18:36.
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Old Sunday 14th July 2019, 18:53   #7
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Anymore than 15X, might as well go APM and use interchangeable Eye pieces. For that other sport, use a scope and a 10X or 12X. 18X seems like a fad to me, it would never replace a scope.

Andy W.
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Old Monday 15th July 2019, 14:09   #8
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Quote:
Originally Posted by [email protected] View Post
" I wouldn't think a 18X56 is going to do THAT much over a 15X56. Of course low light performance is going to be best with the 15X56."

A 15x56 is not necessarily going to have better low light performance than an 18x56 because the "Twilight Factor" of the 18x56 is going to be better than the 15x56. The 15x56 might be brighter because of it's bigger exit pupil but the 18x56 will resolve more detail because of the higher magnification. Here is a resolution test on Youtube where the Vortex Kaibab 18x56 out resolved the Swarovski 15x56 SLC under low light. I think the New Vortex Razor UHD's could be just marketing hype. I had several pairs of Vortex Razor HD's and several pairs of Vortex Viper HD's and I thought the Viper HD's were just as good as the Razor's. I just bought a Vortex Viper HD 12x50 and it is an excellent 12x for under $500.00. MIC but no quality problems at all. If I were you and you want an 18x56 I would buy the Vortex Kaibab 18x56. Here is a new one on Ebay for $899.00.

https://www.ebay.com/itm/Vortex-Kaib...0AAOSwRkJdJ3KL
https://www.youtube.com/watch?v=SYoU7ZSX0FQ
775/5000
Hello, I have just received the new Razor UHD 18x56 and I have only been able to make a couple of observations with them, I used a tripod and I must be honest, to be so powerful with 18x the image is very clear. I thought it was I would see something dark, but it was not like that, I have the Razor HD 12x50 and although they are two different powers, the 18x has very good lighting and sharpness, I am very happy with these 18x56 UHD. I use them for observations of natural landscapes and see airplanes, I love this. When I use them without a tripod although they have a weight of 41.6 oz they feel very manageable in my hands, the Zeiss Conquest 15x56 HD is much heavier and tiresome in my hands, conclusion, I give 4 stars of 5 to these Vortex UHD in my very personal opinion
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Old Monday 15th July 2019, 15:15   #9
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Some time ago, I was able to observe a Canon 18x56 stabilized and the resolution was fantastic although when pressing the magic button there was some kind of "artifact" in the image, let's call it "tremor" or something similar ... for astronomical observation also very good , the Moon fantastic! I imagine that this model of Vortex will have good quality too ... no?
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Old Monday 15th July 2019, 23:44   #10
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Quote:
Originally Posted by [email protected] View Post
" I wouldn't think a 18X56 is going to do THAT much over a 15X56. Of course low light performance is going to be best with the 15X56."

A 15x56 is not necessarily going to have better low light performance than an 18x56 because the "Twilight Factor" of the 18x56 is going to be better than the 15x56. The 15x56 might be brighter because of it's bigger exit pupil but the 18x56 will resolve more detail because of the higher magnification. Here is a resolution test on Youtube where the Vortex Kaibab 18x56 out resolved the Swarovski 15x56 SLC under low light. I think the New Vortex Razor UHD's could be just marketing hype. I had several pairs of Vortex Razor HD's and several pairs of Vortex Viper HD's and I thought the Viper HD's were just as good as the Razor's. I just bought a Vortex Viper HD 12x50 and it is an excellent 12x for under $500.00. MIC but no quality problems at all. If I were you and you want an 18x56 I would buy the Vortex Kaibab 18x56. Here is a new one on Ebay for $899.00.

https://www.ebay.com/itm/Vortex-Kaib...0AAOSwRkJdJ3KL
https://www.youtube.com/watch?v=SYoU7ZSX0FQ
Wow! "Twilight Factor" is such a NEW concept to me!

Of course I considered twilight factor....BUT I also considered that the 15X56 will have a 3.73mm exit pupil and the 18X56 has an 3.11mm exit pupil. All but the very dead are going to have pupil dilation of greater than 3.11mm at dusk. Most are going to have more dilation than 3.73mm too. So I'll take the 15X56 and run with it and I bet I'm in the majority and I'll take any bet that I'm correct too!

One internet "test" does not a result make. You are old enough to know that. Who did the test? Are they affiliated with Vortex at all? Doesn't that sound fishy?
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Old Tuesday 16th July 2019, 05:58   #11
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.........? So I'll take the 15X56 and run with it and I bet I'm in the majority and I'll take any bet that I'm correct too!.......
I wouldn't be too hasty.

Of course it all depends on what what metric you use to judge performance and the exact light level you mean, but you are stacked up against studies by Zeiss, Leica (Leitz) and at least three US universities.

David
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Old Tuesday 16th July 2019, 15:08   #12
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Wow! "Twilight Factor" is such a NEW concept to me!

Of course I considered twilight factor....BUT I also considered that the 15X56 will have a 3.73mm exit pupil and the 18X56 has an 3.11mm exit pupil. All but the very dead are going to have pupil dilation of greater than 3.11mm at dusk. Most are going to have more dilation than 3.73mm too. So I'll take the 15X56 and run with it and I bet I'm in the majority and I'll take any bet that I'm correct too!

One internet "test" does not a result make. You are old enough to know that. Who did the test? Are they affiliated with Vortex at all? Doesn't that sound fishy?
if you are looking for detail at twilight you will see more with the 18x56 than the 15x56. I have personally observed it myself many times with binoculars of various formats. The 15x56 will appear brighter. The extra magnification makes seeing detail easier even under low light just like it does in daylight. Chuck you said in another thread that you actually preferred more magnification over a bigger exit pupil in twilight yourself.

"The difference in a 8X56 and 10X56 is....not much. Most of the comparisons I've done have been at dusk and not true darkness. I would prefer a 10X56 every time."

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Old Tuesday 16th July 2019, 17:13   #13
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I wouldn't be too hasty.

Of course it all depends on what what metric you use to judge performance and the exact light level you mean, but you are stacked up against studies by Zeiss, Leica (Leitz) and at least three US universities.

David
David,

Are you saying Zeiss, Leica, and 3 US universities have all proven a 15X56 is better at low light than a 18X56? If so, I'd sure like to see that.

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if you are looking for detail at twilight you will see more with the 18x56 than the 15x56. I have personally observed it myself many times with binoculars of various formats. The 15x56 will appear brighter. The extra magnification makes seeing detail easier even under low light just like it does in daylight. Chuck you said in another thread that you actually preferred more magnification over a bigger exit pupil in twilight yourself.

"The difference in a 8X56 and 10X56 is....not much. Most of the comparisons I've done have been at dusk and not true darkness. I would prefer a 10X56 every time."
Dennis,

I sure did not say that. Did you completely miss the 8X56 and 10X56 in the post you are referring to? No mention of 15X56 OR 18X56.

10X56= 5.6mm exit pupil
15X56= 3.73mm exit pupil
18X56= 3.1 mm exit pupil

That's a LOT of difference...5.6mm to 3.1mm...

A straight quote off of swarovskioptik.com:

Twilight Factor

The twilight factor defines the optical system’s performance in poor light. The statement “the greater the twilight factor, the better the suitability for twilight” only applies if the exit pupil is larger than or at least as big as the eye’s pupil.
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Old Wednesday 17th July 2019, 02:05   #14
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There's never been a Vortex I'd buy before a Meopta Meostar. The new Vortex UHD pricing is an absolute joke, almost as ludicrous as the Blaser bino's price.
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Old Wednesday 17th July 2019, 06:21   #15
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Chuck,

I think most of the optics industry has forgotten that when Köhler and Leinhos of Zeiss published their results they specifically stated that the formula usually referred to now as the 'twilight factor' only applied to the range of leight levels between 0.1 and 0.003 stilb or cd/m2 in SI units. That means moonlight to most of us. At higher light levels magnification is the predominant factor and below that exit pupil.I think most birders would be on their way home well befor the twilight factor formula applies.

Although they didn't go beyond 15x, they found that at levels above the TF light level range and what we might call birding twilight, a 3.3mm, 2.3mm and 1.6mm exit pupils made no difference to the average apparent acuity in their study. Certainly their work predicts that an 18x56 would show more detail than a 15x56 for our kind of use.

Berek from Leitz (Leica) took a rather different approach. He looked at the threshold of target detection. My understanding is that magnification is significantly more important at moonlight levels and beyond than for apparent acuity, but again in birding twilight magnification in the primary determinant. It's a very long time since I had a look at the US studies, but as I recall they came up with very similar findings to Zeiss but produced much more complex formulae.

There appear to be a couple of things going on here. In normal daylight the detail limiting factor is optical resolution of the lens complex of the eye. It seems the potential optical advantage of a dilated pupil is normally offset by increasing aberrations. So, on average, the acuity is more or less constant over much of the daylight (photopic) range. It is at the onset of twilight where the eye starts to switch between daylight colour vision and night monochromatic vision that the retinal illuminance increasingly determines not only the level of detail you can see but also the threshold of contrast detection and starts to explain Köhler and Berek's results. I should point out that all these studies were probably conducted on conscription age men and our results mat differ. Holger factored in age in his paper on the subject.

Just to add a little twist to this story. All those studies were done on fixed black and white inert targets, but is that how things always work? I've had a just a few attempts at trying to see how magnification and exit pupil work for me. I've seen enough to be satisfied that both the acuity and contrast approaches work more or less as predicted by those studies for me. However on a couple of occasions animals have appeared in the field. A cat hunting a mouse at the bottom of my garden on one occasion,and a fox hunting a rat on the far side of the field out the back on the other. It was absolutely obvious that both the threshold for detection and the level of visible detail increased dramatically, when I detected movement, and magnification was the main determinant deep at those moonlight light levels. We know our brains exercise some control over the way the eye functions and most certainly how the incoming information is processed. Just seems it might shift up a gear when predators or prey are involved. I've found no relevant publications on this subject, but at least in principle it might make evolutionary sense.

Cheers,

David
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Old Wednesday 17th July 2019, 07:07   #16
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Nice discussion David.

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Old Thursday 18th July 2019, 22:32   #17
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David,

That IS interesting.... Wouldn't black and white targets give the advantage to magnification? What kind of optics did they use in these tests?

When using spotting scopes I don't really find this to be true. I can go from 25-30X to 70X with a 82-88mm objective. On cloudy overcast days during early morning/late afternoon(poor light conditions), I can get to a point where the magnification tends to overwhelm the objective size. In other words I can't use maximum magnification in poor light conditions because the subject/image becomes too dim for identification.

I'll play Devils Advocate.... Since exit pupil size doesn't matter as much as magnification in these test....would you rather have an 12X30 OR a 10X56 at dusk?
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Old Friday 19th July 2019, 04:05   #18
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Here's a nice resolution test which supports my observation's that the Vortex Viper HD is very close to the Vortex Razor HD in performance for way less money.

https://blog.sandsarchery.com/2018-o...ular-shootout/

Last edited by [email protected] : Friday 19th July 2019 at 05:25.
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Old Saturday 20th July 2019, 08:07   #19
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Chuck,

I'm sure the choice of target was a factor in those results. They also looked at 0.3 fold contrast and produced rather similar response curves. The contrast threshold approach by Berek that was the subject of Holger's paper appears tomhave a more practical relevance to me, but both these studies were really exploring lower light levels than most birding.

All the studies I referred to used binoculars. It looks like the Zeiss subjects were young with better than 20/10 eyesight which might explain how they were able to get the equivalent of 20/10 results with a 1.6mm exit pupil. I don't know about you, but I couldn't match that any more. Personally I find it counterproductive to go beyond a 1.8mm exit pupil, or about 45x with an 82mm scope, due to the decrease in contrast, and limiting resolution. Others will differ of course.

A 12x30 or10x56 at dusk? It rather depends on how you define dusk. In terms of level of detail the 12x30 would normally have the advantage for me, in terms of effective acuity for at least some time after sunset, (in the summer months). A 12x50 would have the advantage over 10x56 for longer than you might imagine, but once into moonlight levels the 10x56 would win out. Choose a different measurement of binocular performance and you would get a different answer.

David
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Old Saturday 20th July 2019, 08:10   #20
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Dennis,

That isn't a resolution test. It's called a brand and model awareness study.

David
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Old Sunday 21st July 2019, 05:53   #21
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As David indicates in posts 15 & 19, there are a whole range of considerations, including variations depending on the light intensity/ degree of darkness

For the technically inclined, Holga Merliz ( http://www.holgermerlitz.de/bino_per...rformance.html ) has both:
- provided a link to 2 original articles by Berek (in German)

- and has also published a 2015 article in English, explaining the work of Berek and others - see the attached PDF

And Danial Vukobratovich’s 1989 article ‘Binocular Performance and Design’ also explores several of the same issues - again see the attached PDF
(it’s from: https://wp.optics.arizona.edu/optome...ovich-1989.pdf )


I’ve also attached 3 graphs from Merlitz and 1 from Vukobratovich as an encouragement to look at the articles
While I’ve read through Holga’s article on several occasions, due to the amount of detail (even when setting aside the equations), I still don’t think I fully understand all of the points made in it!
However as an encouragement, I’d suggest first starting with the summary at the end, and then going back to the start of the article

continued . . .
Attached Thumbnails
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File Type: pdf Performance of Binoculars, Merlitz 2015.pdf (211.9 KB, 5 views)
File Type: pdf Binocular performance & design, Vukobratovich 1989.pdf (866.2 KB, 3 views)
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Old Sunday 21st July 2019, 05:55   #22
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and the graph from Vukobratovich


John
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Old Sunday 21st July 2019, 09:03   #23
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John,

Since it was a Twilight Factor comment that launched this discussion, I thought it best to mostly stick to effective acuity, but would agree that Holger's paper, based on the work of Berek on threshold contrast is very important too. Unfortunately the mathematics puts a lot of people off, but it's worth persevering as you say.

The Vukobratovich plot has been posted here quite a number of times, but thank you for the complete article. It has somewhat confirmed my suspicions that the plot is rather out of date. Coating technology in particular has advanced conserably and I've certainly found that the supported binocular results are virtually indistinguishable from the theoretical with the better modern roofs.

I'm sure we are all familiar with the detrimental effects of hand shake. It's something that varies considerably between individuals, but muscle tension, load and duration are some of the contributing factors. Modern designs and use of high tech materials have provided us with a much wider range of options for weight, balance and comfort in the hand than there were prior to Vukobratovich's paper. I certainly find some binoculars much steadier than others, and for the best examples, hand held, the efficiency line would be quite linear between 6x and 12x.

Just to come back to the twilight story. I noticed when I did those binocular comparisons in near darkness that the effect of shake on visible detail almost disappeared. The loss of acuity due to shake was swamped by the loss of acuity due to low light levels. A 6x and 12x seemed equally shake free to my eyes, though my hands told a different story.

Cheers,

David

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Old Sunday 21st July 2019, 15:16   #24
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Dennis,

That isn't a resolution test. It's called a brand and model awareness study.

David
Even the authors said it was a far from scientific study but it still makes me feel good when 50 people agree with me that there is not a lot of difference between the Vortex Viper HD and the Razor. I have always thought the Vortex Viper HD's were a good value at their price point.

"The huge surprise to me and just about everyone was how well the new 2018 Vortex Viper HD’s ($499) performed. They were right behind the Vortex Razors in every category, and tied the Razors on the score target. I am pretty much convinced that if you had both the Razors and the Viper HD’s side by side, I would have a hard time telling them apart. They were really that good. With a street price of under $500, the Viper HD’s are definitely the best bang for your dollar. Look for a detailed review later this summer!"

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Old Sunday 21st July 2019, 17:38   #25
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Dennis,

In all likelyhood there wasn't a single person out of that test group that could spot a resolution difference between any of those binoculars using that chart, and as an average of 50 users, not a hope in hell. I'll try to explain why.

I'll assume that target they used was printed to scale and the distance was 70 yards, though it doesn't actually make any difference to the arguement if they weren't. The numbers on the chart are cycles per millimetre. With a distance of 70 yards you can convert quite easily to a 20/20 acuity scale. So that first value of 0.25 on the chart becomes 20/21.5 and so on.
0.25 = 20/21.5
0.28 = 20/19.2
0.32 = 20/16.8
0.35 = 20/15.3
0.40 = 20/13.4
0.24 = 20/11.9

Those first column values would cover the acuity range of a typical random selection of 50 individuals between about 15 and 65. The critical line for distinguishing the best from worst in that binocular group would be the 0.71 pattern in the second column or 20/7.5. The best theoretically possible result would be 20/6.4. It is very unlikely that anyone in that test could distinguish between those binoculars using such a test chart with a naked eye. I guess it is possible that someone in that club had truly exceptional acuity, but it most certainly couldn''t explain a 30% difference in total resolution score between best and worse result.

The organisers were quite aware of the potential problem with such a test. " We found last year that there seemed to be a lot of brand loyalty going in to some of the responses, and we thought that the numbered target would help see through some of that...." Evidently it didn't solve the problem.

Dennis, I believe you when you say you cannot tell the difference between a Viper HD and Razor HD, and apparently 50 other people couldn't either but I'm sorry, this 'test' is no evidence that there isn't one.

Hope that makes sense.

David

Last edited by typo : Sunday 21st July 2019 at 17:40.
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