The search for the perfect set of “big eyes” for long-distance glassing

Glassing with Swarovski BTX and 95 objective

Glassing with the Swarovski BTX and 95mm objective. Photo credits: Brady Miller

I’m always looking for an edge… a way that I can become a more efficient mule deer hunter. This past year I was searching for a way to potentially increase my chance at spotting a big old mule deer buck in the mountains. That search lead me to re-visiting my glassing techniques.

I absolutely love glassing, and while there are a ton of ways to outsmart and kill an old buck, there's something to be said about having a solid glassing plan along with a level of patience and level of detail in your glassing that can set yourself apart from others on the mountain. Even with me thinking that way and always trying to pick apart the mountain to the best of my ability, I still know there are times when I’m not glassing as hard as I could be. So this past 2020 season I revisited a bunch of the “big eye” glass options and really sat down to carve out what might work best for me. I looked at a bunch of options over the years and this past season. Most of these options I've used/borrowed while hunting or scouting for a brief period of time and I’m thankful for great friends who let me use their glass for a bit.

As stated earlier, I absolutely love glassing and those that have hunted with me, know I love glassing for long periods of time with my spotting scope. But as you can imagine, long hours spent squinting my left eye while trying to stay focused with my right eye, can make for a tough day of glassing.

When talking about "big eyes" and even high-power spotting scopes, both Cody Nelson and I agree that these options really shine when you are looking for "tomorrow's buck." Big eyes are for glassing giant open places. This means you are leaving animals totally undisturbed while at the same being able to really watch their patterns to make a play for them another day because you might not be able to hunt them that same day. After some long-distance glassing, you can hunt them the next morning after making a plan, moving camp or relocating around the mountain to put yourself in position. But... that isn't all big eyes are useful for. While I'll definitely use my system this way, big eyes have really helped me to pick apart the terrain to ensure that I leave no brush, rock, or piece of shade unturned. This is where I hope to gain an edge in my glassing efforts. So while big eyes are phenomenal for glassing animals at greater distances, they also allow you to see all the details of a mountainside much clearer.

I’ve glassed and hunted with the following “big eye” options the past several years:

  • Docters
  • Kowa High Lander
  • Kowa twin spotting scope with bracket
  • Swarovski BTX
  • Swarovski twin spotting scope with bracket
  • And also several "normal" spotting scopes

After looking at everything out there, I decided to go with a Swarovski BTX system.

Why I decided to go with the Swarovski BTX system

After all my testing and constant phone calls to our Optics Manager Cody Nelson, I landed on my dream optic! The "big eye" option I was most excited about and the one I ended up purchasing was the Swarovski BTX with a 115mm objective (more on the 115 vs 95 below).

When a hunt concludes, I always analyze what worked and what didn’t work and what I could do to improve my hunts. I felt like the BTX system is going to be the ticket for my mountain mule deer hunts and will also be a huge addition to my scouting efforts. Plus, it will be a great system even on those hunts when I don’t go crazy deep into the mountains.

Also, after looking at all of the other “big eye” options on the market, I was sold on the modularity of Swarovski’s system. Even though at this time I’m only going to be using the BTX eyepiece, I can see myself saving up for the ATX Angled Eyepiece down the road. The modular system is something out of a dream and allows you to pick and choose what eyepiece and objective lens you want to take on a particular hunt.

Using forehead rest on Swarovski BTX

Forehead rest means all-day glassing comfort.

With a BTX you can see more and appreciate the comfort of glassing with two eyes open all day through high magnification than you would experience with binoculars mounted on a tripod. Plus, the forehead rest is something that I have greatly enjoyed using during long glassing sessions.

A little weight definitely goes a long way, especially because most of you will remember that I’m still fairly weight conscious (until it comes to my weapon and to a degree my optics), the optics I use get carried on my back at all times.

Why did I go with the 115 over the other objectives?

I’ll be honest, at first, I was dead set on the 95mm objective for the BTX. I called Cody Nelson on the phone back in November and while he was telling me about all the benefits of the 115, I thought it was not going to work for my backpack-style mule deer hunts. After all, 99% of the hunts I go on I have to pack everything on my back as I typically don’t rent llamas that often. At that time I told him I’d like to place an order for the 95mm.

Fast forward to the following morning and I again called Cody bright and early. The first question I asked him was, “Will I eventually regret my decision of going with the 95 objective over the 115?” His answer really hit home to me. He said, “Brady, I’m going to be honest with you, I fully think that how you hunt, you will eventually regret your decision.” He continued on to say, “With your glassing style, you will absolutely love the 95, but once you get used to the 95, you might start glassing further away at first or last light trying to save your legs and all of a sudden you are going to wish you had the bigger 115 objective when you’re trying to locate a big old buck.” Plus with all the digiscoping I do, he said the 115 would be phenomenal through the BTX and then if I ever decide to get the ATX eyepiece, digiscoping would also shine with the 115 on the front.

While the 115 is going to fill up a bunch more space in my backpack and it adds more weight, but as I like to say, you can’t hunt what you can’t find.

My experience so far with the BTX

Swarovski BTX setup for hunting

I purchased the BTX eyepiece from the goHUNT Gear Shop right before I left to help my family on a mule deer hunt in November of 2020. Note: I actually did purchase the BTX with my money, as it's something I felt that confident in. Also, at the time, all of the 115mm objectives were sold out. What happened next really speaks to Cody Nelson’s level of dedication to helping people. Since the 115’s were going to be out of stock for a while, he told me that I could borrow his person 85mm objective until a 115 showed up to purchase. This meant the world to me! He then boxed up his 85mm and since I was leaving in a day, he went ahead and overnight shipped the objective close to where I was hunting. That level of dedication to helping out truly means the world to me!

On the hunt with my family, I used the BTX for all my long-distance glassing. Every time I sat behind the BTX I couldn’t help but smile. I've used the BTX system a bunch in the past thanks to friends, but once I owned one myself and put more time behind it, I can now see what all the hype was about. While on this hunt I even used the BTX with a window mount system and I found that for this to really work effectively, I needed to add some clothing under my backside so I could sit up high enough to glass out of a vehicle with the BTX. This is a slight downside with the BTX as before with an angled spotter, I could just twist the body and keep glass comfortably from a vehicle. But honestly, this wasn't a dealbreaker for me. Going forward if running around and glassing long distance from a vehicle, I'll just carry an ATV cushion or something similar when I scout out a unit at distance in the summer.

This winter, I borrowed a 95mm objective from my friend Blake. I took the 95 to Arizona on an OTC Coues deer hunt, and again I used the 95 on a javelina hunt in February. I really enjoyed the 35 power that the bigger objective gave me.

Glassing with two eyes = gamechanger!

Brady Miller glassing with Swarovski BTX

Photo credit: Logan Summers

Once you sit down and really pick apart terrain with both eyes through the BTX, you will quickly realize how comfortable and enjoyable glassing can be. And Cody was right, it really seems like you are looking through an optic with more power because you are using two eyes rather than one. In the past, I probably glassed with my spotting scope as much as my 12 power binoculars and that trend is going to continue now that I can use both eyes open with more magnification in a BTX.

Swarovski BTX specifications

Let’s look at the details of running a BTX with various objectives.

 Swarovski BTX Eyepiece
Weight3 lbs. 2 oz.
Power65/85mm = 30x
95/115mm = 35x

Swarovski modular objective lens specifications

Comparison of Swarovski optic objectives

Photo credit: Cody Nelson
Objective lens
Weight1 lb. 11.3 oz2 lbs. 6.8 oz2 lbs. 15.3 oz4 lbs. 6 oz.
Power RangeSTX/ATX = 25-60x
BTX = 30x
STX/ATX = 25-60x
BTX = 30x
STX/ATX = 30-70x
BTX = 35x
STX/ATX = 30-70x
BTX = 35x

Weight and size of BTX with the various objectives

 BTX + 65mmBTX + 85mmBTX + 95mmBTX + 115mm
Weight4 lbs. 13.3 oz5 lbs. 8.8 oz6 lbs. 1.3 oz7 lbs. 8 oz
Exit pupil
Power RangeBTX = 30xBTX = 30xBTX = 35xBTX = 35x
Total Price$3,828$4,518$4,898$5,768

The 95mm vs. the 115mm

Swarovski BTX system with 95 and 115 objective

Photo credit: Cody Nelson

The 95 and the 115 objectives were the ones I was most interested in purchasing. When you go from a 95 to a 115, you are talking about an increase of 22.7 ounces. Besides the discussion with Cody Nelson that I already mentioned, I figured it would make more sense to go with the 115 to start, then if at some point down the road I was looking to save some weight, I could pick up the 85mm. This way I would have a light option and a heavy option that are not so close together in terms of size/weight. I'm really looking forward to taking the 115 out and comparing it to my friend's 95 to see what the difference in brightness would be.

Let’s compare the other options I’ve glassed with

As mentioned earlier, I wanted to check out all my options before I purchased something.

Kowa High Lander

Glassing with Kowa High Lander optics

Blake Richardson glassing with his Kowa High Lander setup.

I only got to look through the Kowa High Lander Prominar's with the 32x wide eyepiece for one day, but I enjoyed every minute with them. That being said, I didn’t enjoy the weight. They come in at 13.6 pounds and are 16.9” long x 9.4” wide x 5.9” tall, and because I love backpacking, these just don’t fit in my style of hunting. Another part I didn’t like was having to focus each eye individually all the time. This isn’t a real dealbreaker as I was able to figure out how to establish a common focus point, but it's something to consider.

To me, these really shine if you are just glassing from a road at extreme distances or using them at your truck or ATV. While I loved how bright they were due to the dual 82mm objectives, for my style of hunting where I crave the backcountry, these just aren't feasible for me. But... they could really work well for someone else who might have a different use case, or just wants them for long-distance glassing for scouting. I really appreciate Blake Richardson allowing me to look through these on a deer hunt this past fall!

Docter Optic

Docter’s are another classic example of “big eyes.” I know so many people who use these for picking apart desert bucks at extreme distances. The ones I looked through several years ago were the Docter Aspectem 40x80 ED binoculars. I've only used them very briefly thanks to a good friend Stephen Spurlock and it has been several years ago since I looked through them. The Docters are great, and I feel like they compare very similar to Kowa High Landers. Again, due to the size, I really didn't feel like they were the ones for me. But like I said previously if you are not traveling far from a vehicle, they could be a great option. I do recall them being very bright in low light, but again, it's been a while since I've had the chance to look through them.

Twin Swarovski spotting scope setup

Twin Swarovski spotting scope bracket

A twin Swarovski spotting scope setup is a very interesting option in the long range glassing game. For this setup, you are taking two straight spotting scopes of the exact make and power and you are utilizing a custom-made bracket. Last I checked, you can get the brackets from Wells Manufacturing out of Prescott, AZ.

One thing I enjoyed about the twin Swaro setup was being able to spot something in the distance, and then close one eye and zoom in on the animal to get a closer look. This is something that is missing on the other “big eye” options. Again, like the Kowa's you will need to focus each spotter individually to see clearly. The one downfall I see with this setup is that isn't not easy to have your friend look through them because most likely you and your friend might have a different face structure and the distance between your eyes will not be the same.

The weight of a twin Swarovski setup is roughly 7.5 lbs with the bracket. This setup is more packable than Kowa High Landers or Docter’s, but as you can imagine, two spotting scopes plus a bracket is still a large setup if you are planning on hiking far from your truck. It should be worth noting that this setup is right in line in terms of weight when compared to a BTX and 115mm objective. For some people, it might make sense to jump into a twin spotter setup because most likely you already have a spotting scope that might work for the dual setup. Most people run twin 65 mm spotters. If you went with 85s, the weight would be substantially higher and you would start dipping in the Kowa High Lander territory when it comes to the overall weight of the setup.

"Normal" spotting scopes

I've used what most would consider a "normal" spotting scope for a long, long time. I won't go into a ton of detail here, but this is for sure a setup that can work wonders and I've used a normal spotter for years. The only disadvantage is the eye fatigue of staring through the spotter for long hours.

In summary

Swarovski BTX 85mm objective hunting mule deer

Swarovski BTX with the 85mm modular objective on a November mule deer hunt.

Every person's eyes are different and their glassing use cases are different. After using the BTX system this past fall and winter... I can't wait to take it on several backpack hunts. It's going to add some weight and bulk to my backpack, but you can't kill what you can't find. While I will miss adjusting the magnification of a normal spotting scope, especially when watching a shot for a friend, or those times when I might need to really judge a buck. But I feel like I'm gaining a huge edge in other areas of the glassing game when I just want to find bucks.

Also, while I’m looking to gain an edge on my hunts, this nowhere means I’m going to rely solely on glassing to find deer. If you just do that you are leaving things on the table. You need to be a well-rounded hunter in order to take big mule deer in my opinion. This BTX and 115 objective is just another sharp tool in my toolkit.

If you have any thoughts or questions, definitely drop a comment on the article and I'll get back to you. Also, you can reach out to our Optics Manager Cody Nelson. He is a wealth of knowledge and I can't stress enough the importance of taking advantage of Cody's knowledge when deciding what optics to purchase. Cody can be reached at or call him at (702) 847-8747.



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