Feb 052019

Every year I tell myself that I will look at spotting scopes more since they are interesting and since it is easy for me to look at them: set up a few tripods on the deck and go for it. This year, I am actually going to do something about it.

One thing that is of interest to me is looking at different spotting scope types, which is exactly what I did in the video below.

65mm Vortex Razor HD is a conventional spotting scope, albeit with a new wide angle variable eyepiece (I also have the absolutely excellent fixed power eyepiece for it).

Athlon Cronus 7-42×60 is built more like a regular riflescope inside except without the need for moving the reticle and with short eye relief. US Optics used to have a spotter like this and Bushnell’s LMSS is a somewhat similar design. There is an optical compromise there: spotters of this type usually have a little worse image quality (multi-lens erector system instead of the prism), but they have an advantage in magnification range. In the case of the Cronus, I can use it handheld on lower powers or off a backpack or tripod as magnification goes up. These are also comparatively rugged inline systems, so the Cronus lives in the side pocket of my backpack and does not seem to be adversely affected in any way.

Meopta TGA 75 is another in-line design except it is does use an erecting prism. The interesting part about this one is the collapsible body. There aren’t a whole lot of these out there, but I am pretty impressed with this one, especially with the 30x eyepiece that has a reticle in it.

This is not really intended as a comparison, per se, since these are very different designs, but looking at them side-by-side is interesting as they work best for different applications. There is a lot of personal preference in selecting the right ergonomics. For example, modern wide angle eyepieces are excellent, but they bump my nose, so I have to look through the scope sideways, which induces strain. In other words, there is no replacement for actually using these things. A wide angle eyepiece may look great, but it gives me trouble for prolonged observation. Generally, for a lot of what I do, I really find myself drawn to fixed power eyepieces with longish eye relief. Meopta with a fixed power 30x eyepiece is a little limiting since it is a little wider than I like for scanning, but it has good FOV, so it works well for me. Vortex Razor HD with a fixed power eyepiece is just a joy to use, but 18x is a little on the low side for a spotter. A good 15x “Big Eyes” binocular will give you about the same image quality with less eye strain due to using two eyes and you need a tripod for either of these. The same eyepiece with the larger 85mm Razor is a 22x and you can get it with a reticle. That is a very nice setup.

In terms of sheer flexibility though, Cronus with its 7-42x magnification range is really difficult to beat.

One of the things I have been trying to ascertain last year, is how using a high magnification binocular compares to using a spotter. There is a tradeoff between magnification and using two eyes. What I found is that exit pupil still matters. I played around with a nice 20×56 binocular and some 15×56 ones and found that for reasonably relaxed viewing with big binoculars, I need more than 3mm of exit pupil. I can see more with a nice 15×56 binocular than with 18-20x spotter with 50-60mm objective, for example. However, Vortex 18x eyepiece with a 65mm spotter has some significant advantages in low light even with only one eye in use.

One approach I have not spent too much time looking into usign a doubler or tripler with a “Big Eyes” binocular. That could be an interesting “jack of all trades” approach.

Here is a spec table for the spotting scopes I discussed in the video above.

Vortex Razor HD 65mm
22-48x or 18x LER
Athlon Cronus
7 – 42×60
Meopta TGA 75
20-60x or 30x WA
Length, in15.613.914.5 (w/o eyepiece),
10″ collapsed
Weight, oz56.846.644
Exit Pupil, mm3 – 1.45.2 – 1.43
FOV, ft @ 1000 yards138 – 84 (w/ 22-48x)
163 (w/ 18x)
284 – 47.6114 (w/30x)
943- 48 (w/20-60x)
Eye Relief, mm17 (w/ 22-48x)
31 (w/ 18x)
Close Focus, ft261014
Price$1200 – $1500$1000$1200 – $1500
 Posted by at 2:23 pm

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