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Coatings on objective lens - variations

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#1 FOTKM

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Posted 15 May 2019 - 05:57 PM

I have a pair of vortex viper hd 12x50s (2018 edition). The one I originally bought was returned to Vortex under warranty as it wasn't focusing properly. I noticed the replacement had the word "Vortex" on one of the barrels and others that I saw in stores have "Viper HD" on them (see pic attached). Even more interesting is the one with Vortex seemed to have a very light brown optical coating on the objective while the Viper HD's objective coating was more deep purple/red which is more typically seen in binoculars. I asked Vortex what the differences are between these two samples. Here is their response:

 

"There is no difference between the two, it was simply due to a copyright issue within the country of manufacturing - instead of halting production while it was addressed they elected to just change the label.

Coatings on lenses can be different colours depending on how long it took the coatings to dry, which can be impacted by a number of different factors. There is no actual difference to the coatings, and it will have no impact on the optical function of the lenses."

 

They did this on the 2016 Diamondbacks as well and changed the focus knob which was a bit sloppy when it first came out. My only guess is they found some issues with manufacturing and changed the label to distinguish the new from old.

 

Their explanation regarding the different colour coatings is interesting as well. I'm no expert when it comes to this so I would like to know what others think. I'm almost wondering if the first release wasn't even fully multi-coated as they claim. These are all made in China.


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#2 ngc7319_20

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Posted 15 May 2019 - 07:19 PM

As for the coatings, the important thing is how much light is reflected.  The color of the coatings does not mater so much.  You can have red / green / blue / violet / brown / etc. coatings that are either great or poor.  As an example, I recently bought 3 supposedly identical eyepieces from a top US maker, and coating colors are all over the place.  The important thing is all have nice dark (low reflection) coatings.  It probably depends on what the guy making the lenses in Taiwan, Japan, etc. decided to use that day.  The bino company (or eyepiece company) probably only specifies "broadband coating with less than 0.5% reflectivity per surface" and the coating guy does something reasonably in accordance.  Maybe the lenses even come from different factories, but meet identical specs provided by the eyepiece or bino company.



#3 Rich V.

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Posted 15 May 2019 - 08:22 PM

Yes, your primary concern is the intensity of the reflections, not the color.  The faintest reflections indicate the highest transmission.  A handy test is to look into the lenses and see how much of your facial details you can see reflected back at you.  The highest transmission coatings will show very little detail.

 

An example of reflection intensities from plain glass, MgF2 coatings and two samples of multi-coatings:

 

https://www.csun.edu...d/coating2.html

 

Rich


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#4 Foss

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Posted 16 May 2019 - 09:38 AM

Thanks Rich V for the link.




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