Swarovski ATX/BTX Review, By Matt Cashell

[CL&RR]

I've been looking at the BTX for a number of years now. Good review.

 

[Awaldier]

Thanks for the info!

 

[WestHunterTNT]

Matt just finished up his review of the Swarovski ATX/BTX system. Give it a read to see how this glassing system worked for him.

Swarovski ATX/BTX Review

Also, don't forget to check out this podcast where Matt discusses a bunch of different optics with host @Jordan Budd.

i have the BTX with extender and a 65mm objective.... really love the glass and eye relief versus a single eye optic

But I did notice that in low light conditions the 65mm did not pick up enough light and my view was not as bright as my buddy (sitting next to me) with a single eye objective - gmfood for thought in early morning and late day/dusk glassing

 

[Matt Cashell]

i have the BTX with extender and a 65mm objective.... really love the glass and eye relief versus a single eye optic

But I did notice that in low light conditions the 65mm did not pick up enough light and my view was not as bright as my buddy (sitting next to me) with a single eye objective - gmfood for thought in early morning and late day/dusk glassing

Interesting experience. Was the single eyepiece 65 also at 50x when you compared brightness?

The extender does cut down on light transmission because of the additional elements.

 

[WestHunterTNT]

Interesting experience. Was the single eyepiece 65 also at 50x when you compared brightness?

The extender does cut down on light transmission because of the additional elements.

The single eyepiece was not on a Swaro.... and it was on maybe a 75mm objective - not apples to apples so I wouldn’t want to draw a conclusion

I might test the low light with the extender versus no extender.... I had an instance last year where I could see a bull on a ridge better with my 10x42’s at dusk than the BTX/65/Extender - made me think about the light transmission a little differently

 

[Matt Cashell]

The single eyepiece was not on a Swaro.... and it was on maybe a 75mm objective - not apples to apples so I wouldn’t want to draw a conclusion

I might test the low light with the extender versus no extender.... I had an instance last year where I could see a bull on a ridge better with my 10x42’s at dusk than the BTX/65/Extender - made me think about the light transmission a little differently

Oh I see.

That all makes sense now. It is all about exit pupil. As your eyes’ pupils dialate in low light, optics with large exit pupils will provide a much brighter image.

The larger objective 75mm spotter will have a noticeable exit pupil advantage at the same power of the BTX.

The 10x42s will have an even better advantage with the relatively huge 4.2mm exit pupil vs. the 65mm extender-equipped BTX’s tiny 1.3mm exit pupil.

Same story with the BTX with and without the extender. The 65mm BTX exit pupil swells from 1.3mm to 2.16mm when you take off the extender.

 

[AkMtnRunner]

Would there be any brightness reduction due to the light being divided between the two eyes? I am not sure how that works.

 

[WestHunterTNT]

Would there be any brightness reduction due to the light being divided between the two eyes? I am not sure how that works.

That’s what I was thinking - and my 65mm wouldn’t be enough to support 2 pupils

 

[Matt Cashell]

Would there be any brightness reduction due to the light being divided between the two eyes? I am not sure how that works.

Yes, there is brightness reduction, but that is offset by a phenomena called “binocular summation” which increases apparent brightness. The result is a bino viewer loses a little theoretical brightness vs. a single ocular.

However, in my opinion apparent brightness between the BTX and ATX on the same objective is pretty similar in actual use.

 

[Jbone62]

First time posting so I hope I am doing this right... I have been looking at the btx vs the swaro 15x and am stumped on which one would suit me the best...

At what ranges would the 15x perform better than the btx? Normally I just have 8x binos and maybe a spotting scope here in the CA A-zone. However it looks like I might be moving out of state here shortly along with a substantial pay bump... looking for some opinions from people who have actually handled them.

 

[Matt Cashell]

First time posting so I hope I am doing this right... I have been looking at the btx vs the swaro 15x and am stumped on which one would suit me the best...

At what ranges would the 15x perform better than the btx? Normally I just have 8x binos and maybe a spotting scope here in the CA A-zone. However it looks like I might be moving out of state here shortly along with a substantial pay bump... looking for some opinions from people who have actually handled them.

Welcome to the forum!

I have used both and would take the BTX over the 15s in just about any situation I would be using one or the other. The ranges overlap substantially. I always have a lower magnification binocular with me for glassing closer or quicker anyway.

You could start your own thread in the optics forum on this topic and get a range of opinions.

 

[Rent Outdoor Gear]

As always Matt - Great Review! For guys that would love to try this system out, we carry the ATX/BTX eyepieces and all three objective sizes and the 1.7X extender at www.RgunsNgear.com where you can RENT any combination you want and we'll credit up to 7 days of your rental directly toward purchase if you fall in love with it! Take a BTX on your next hunt!

Darin Cooper
Rent Guns and Gear
[email protected]

 

[WCW]

Anyone have experience with the 115mm objective?

 

[Bigwood]

I use the btx exclusively and really like the aiming scope and the forehead brace. To each their own but give it a try!

 

[SaltyBowman]

I’m thinking the 85 isn’t a compromis. It is undoubtedly the most versatile. For truck based hunts I say run the 115.