Updated in January 2019
I do not look at spotting scopes as much as I used to, but I do keep an eye out. To be honest, high end spotters is not where most of the interesting things in this market happen. Several years ago, spotters in this price range were absolutely excellent and they still are. In terms of image quality, they may be marginally better now, but that is marginal at best. Unless you are looking for something specific, I would not be buying an ultra fancy spotter with my own money. However, there are a few interesting things happening out there which merit noting.
In terms of pure image quality, the large 88mm Kowa Prominar is still remarkable and if all you want is a traditional spotting scope with the best image quality possible in a moderately sized package, go for that. Kowa’s new 55mm Prominar is the best of the compact spotters that I am aware of.
If you want a full-size spotter, but do not want to spend the 88mm Prominar money, Meopta S2 is pretty much a alpha class spotter for a little less money.
Where there is some differentiation is with different features: reticles, modular systems, etc.
For years, my go to reticle spotter was Swarovski STR and I still think it rocks. I have switched to something else since I get easily bored and STR is probably the best I have seen yet. Hensoldt Spotter 60 is in the same league except even more expensive. I like the STR for general purpose use, but Spotter 60 has a little bit of an edge for seeing the bullet trace. Swarovski does have a bit of an edge in low light, probably owing to its larger objective.
With modular systems, two stand out: Kowa Prominar 500mm and Swarovski ATX.
If you are primarily interested in prolonged observation, Swarovski ATX 95mm body with the BTX binocular eyepiece really cuts down on eye strain. I do not like the divorce-inducing pricetag, but it is a brilliant design.
If your primary need is to use it is a telephoto lens that can also take a traditional spotting scope eyepiece, I think Kowa Prominar 500mm telephoto lens is a better solution for use with a camera. I have not seen it much lately, so I need to check into whether they still make it.
Recommendations from previous years.
If you can afford the best you have several options available to you, all of them very good.
In this price range, all products you will find are superb and a lot really depends on you personal preferences.
In terms of ability to see detail, I think Kowa Prominar with 88mm objective lens is the best there is. It will run in the neighborhood of $3k.
Just behind it a several spotters from the “alpha” makers:
82mm Leica Televid HD
80mm Swarovski TM/STM High Definition
85mm Zeiss Diascope FL
Generally, with top end scope ability to see detail roughly tracks the objective lens diameter, with Zeiss offering slightly better centerfield resolution than Leica and Swaro. However, differences are truly minute and, I think, Kowa still resolves better than all three.
However, the image through the Leica “pops” a little more due to higher contrast (traditional Leica trademark).
Keep in mind that eyepiece choice is very important with a number of fixed and variable options available for all of the above.
If you want a smaller premium spotting scope, all of these makers make smaller models as well, with my favourite being Zeiss Diascope 65mm. Once again, all of the “alpha” makers have spotters of comparable quality with 65mm objectives, but I like the fact that Zeiss eyepieces go down to 15x. It comes in handy in low light.
Finally, if your applications lean a bit more toward the tactical end and you are willing to spend $5k, check out Hensoldt Spotter 60. It is a 20-60×72 spotter of the Folded LightPath (FLP) variety. It has an illuminated ranging reticle and absolutely stunning image quality. It suffers a little bit in low light compared to larger scopes like the 88mm Kowa, but on the plus side it has better depth of field that almost any othe rspotter I have mentioned. That makes it work remarkably well for bullet tracing and also simplifies looking for distant objects.