Steiner Peregine 8.5X44 XP

I think you would probably be better off sticking with the Zeiss.

heres what I want to know

 

steiner advertises using indexed matched lenses

 

1) are they the same index matched lenses used by leo??

2) do they use the same method of measurement (as leo) to classify indexed match ??

3) are they riding on an advertising coattail?

4) does indexed matched mean anything??

Dale Clifford wrote: heres what I want to know   steiner advertises using indexed matched lenses   1) are they the same index matched lenses used by leo??

• Sure, why not? (see below)

Dale Clifford wrote: 2) do they use the same method of measurement (as leo) to classify indexed match ??

• Who knows but, it doesn't really matter.  (see below)

Dale Clifford wrote: 3) are they riding on an advertising coattail?

• Probably. (see below)

Dale Clifford wrote: 4) does indexed matched mean anything??

• Ah, now you've hit the crux of the matter.  Yes, "index matched" does mean something - though not what the advertisers want you to think it means.  What it means is that Leupold's marketing dept. found a way to advertise a fairly common, normal part of the manufacture of optics in a way that made it seem new and innovative. That's not to say that the process itself is unimportant, just that they aren't the only ones doing it nor are they likely the originators of the process. In short; what they are doing in their manufacturing plant(s) is not particularly unique but, their ability to develop a marketing campaign to capitalize on it with the consumer market is pure genius.

Edited by lucznik

lucznik, if we could ever get a straight answer on what "index matched" meanings according to Leupold, then I want to know what "Total Light Throughput" means as well.

 

FWIW, Burris has been using "index matched" as well for a couple of years in their ad campaigns.

"Leupold's exclusive DiamondCoat and Index Matched Lens System matches lens coatings to each lens for superior performance and optimal light management. DiamondCoat on exterior lens surfaces provides superior scratch resistance". (www.leupold.com)


Edited by Bird Watcher

That's nothing new! I talked with some customer service technicians on the phone and got the impression that "the less said the better". It was like pulling teeth!

Edited by Bird Watcher

Is this like ordering a military sporter from Century arms and getting a hand picked one for $20 more??

I wanna know how it got in the UPS box if they aren't all hand picked.

lucznik

Your comments remind me of the posting done by Chirs Farris on JIS water-proof standards.

Ain't it fun trying to keep up with all the "little secrets" that are hidden within the optics industry?

lucznik, your explanation of " index matching" is the closest to the description i just got from Steiner with regard to their advertising. It was explained that the "index" was referring to the various types of glass used in the Peregrine XP to optimize light and image quality transfer. My typing stinks so that's the short version from the horses mouth.

 

 

Roy

I wonder what happens when you combine a scope with "matched indexes", "extended twilight lens systems", sealed in space age gases with diamond like coatings and throw in some "total light throughput"??? I guess them deer's just walk right in to ya and surrender....

OK, before we get too carried away here.  When talking about optics, index refers to one optical parameter: "index of refraction". 

 

Index of refraction is the ratio between the speed of light in the vacuum and the speed of light in the material we are looking at here.  Index of refraction, as the name suggests, defines the angle of refraction of glass.  It also defines which fraction of the light gets reflected from the boundary between two materials of different indices of refraction.  For two materials with indices of refraction n1 and n2, the reflected fraction of light (R) will be equal to [(n1-n2)/(n1+n2)]^2.

 

For a common example of light being reflected at the interface between air (index of refraction = 1.00001 or so) and glass (index of refraction varies for different glass melts, but let’s assume it is 1.5 for the time being), R=0.04, or 4% of the light gets reflected (ignoring angular considerations for the time being).

 

In the example above, if you deposit a thin layer of additional material with n=1.25 (or anywhere in between the refractive indices of air and glass) onto a glass surface, you will end up with two interfaces that reflect light: air to “thin deposited layer” and “thin deposited layer to glass”.  However, since the differences between indices of refraction at each interface are smaller, despite the fact that there are two reflections now, the total amount of light reflected is actually smaller.  On top of that, by matching the thickness of the deposited layer to the wavelength of incident light (more exactly, to the quarter of the wavelength of the incident light in the particular material), you can interferometrically cancel out the reflected light.

 

By adding additional thin layers of material of varying indices of refraction, you can minimize the reflection even further.

 

Pretty straight forward so far, right?  When you are doing this in practice, things get a little more complicated.  The index of refraction of glass is different for different wavelengths of light (different colors).  The variation of index of refraction with wavelength of light is called dispersion (think ED glass, for example).  From a coating standpoint, different colors are a major pain: to optimize for a particular color, you need coating layers of different thickness, and of very uniform thicknesses.  There is something called “Abbe number” which is a measure of glass dispersion for visible light.

 

For example, here is a picture of the transmission/reflection profile of cerulin-plus coatings used by Optolyth (I was just reviewing a couple of very nice Optolyth spotters).  You always have to compromise with coatings.  Optolyth made sure there is good transmission of blue light and when you play with their scope in poor light, it shows.  They sacrificed some transmission between blue and green to get a good peak in the blue/violet region that is important in low light.

 

Back to Leupold. I have talked to several different Leupold reps.  They always give me the same speech on how their “index matched” system has the coatings with the refraction indices matched to the type of glass used and glass with the refraction indices matched to the visible light spectrum.

 

Well, anti-reflection coatings, by definition have to be matched to the glass they are deposited on, and glass has to be selected appropriately for the light.  Every manufacturer in the world does it.  It is very good marketing and when they say all this stuff about matching indices, they are not lying.  However, the only thing Leupold invented with regard to this whole index matching thing is the marketing slogan.  They improved their coatings compared to Multicoat4 they used before, and simply came up with a new name for their new coatings.  The rest is bologne.

 

ILya