Update (12/16/22): I received the Swarovski STX 115mm scope. Much bigger and heavier than I expected, at least compared to my older Athlon Optics Argos HD 20-60x85 Spotting Scope I already had. In the first test, I set it up in a back room of my house overlooking a field, with lots of pine trees, which block most of the view beyond them, which is followed by a big lake. To see to or across the lake I have to look through a few small gaps in the trees. Trees are about 50-100 yards away and block most of the lake. But in the sparse and limited clearings, I can see across the lake to the other side (at least a mile away according to Google Maps).
I was able to see a 3-4ft white heron stalking prey in the marsh reeds across on the other side of the lake (at least 1-mile away) pretty clearly. I couldn't see the color of the bird's eyes, but the bird itself was pretty clear and big. My wife was amazed. And the bird definitely was not visible in the slightest by open eye. You have to strain to see the other side of the lake at all...it's mostly a blur. So, to see the bird that clearly was pretty amazing. In the Swarovski spotting scope, it was looming large...taking up 1/4 to 1/2 of the entire view (on nearly full magnification). You could easily see individual features, flaws in the feathers, and so on. We could see it get a small fish and hold it in its beak before swallowing.
And this was on a very overcast day, with light rain, and pretty low light. We had a big damaging cold front just finish moving through at the time. So, I would think that this would be among the more challenging days to spot anything long distance (other than mirage issues). At the same time I think if anything is going to get you an image it would be a Swarovski with the 115mm lens diameter objective. And this seemed to be the case...at low light we clearly saw a (big) bird at least a mile away.
After trying out my new spotting scope, I tried to put up my older Athlon spotting scope next to it to compare, but the heron was gone by the time I got the Athlon set up and I couldn't find anything else small to target on...other than back of some houses on the other side of the lake. I added the ME 1.7x to the Swarovski, but in my initial tests I couldn't tell how much magnification it added. It didn't appear to me to add that much (although I'm sure it does)...but the light, was as expected from adding magnification, even further cut down...so I don't know, in this testing scenario, if it improved things. If the bird was still there it would have been easier to see. But I was having to focus on the back of houses on a lake, so all I had was some larger framing, architectural elements, etc.
I did put up my old Athlon scope to focus on the back of the houses and was surprised that the images I saw weren't all that different magnification-wise (with or without the ME 1.7x). I'm sure it was different...but I just couldn't easily tell just randomly moving back and forth between the two scopes. So, that cheaper $350 Athlon scope is holding its own.
With that said, I assume the better Swarovski glass and the far bigger lens objective diameter will make the Swarovski a clear winner over the Athlon when I test it out on the range tomorrow. I'm going to point both of them out to 100, 300, 800, 1000, 1750, and 2000 yards and see the difference. I'll report back here what I saw.
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