Dark Lord of Optics
Location: United States
Optolyth Collapsible Spotting Scopes
It has been some time since I looked at these spotters, but for some reason I never published a review on them. I suppose it just fell through the cracks, somehow.
They came up in a recent thread, so I figured I might as well pull up my notes and compile my observations.
The two Optolyth spotters I looked at were the collapsible 25x70 and 15-45x80 models.
From left to right: Pentax PF65ED, Optolyth 25x70, Nikon Fieldscope 82mm ED, Optolyth 15-45x80. Please note that the Optolyth spotters are in the extended position.
Here is another shot with the Optolyth spotters collapsed:
One interesting observation is how beefy the Optolyth eyepieces are compared to the Nikon. Unfortunately, the eyepieces on the Optolyth scopes are not removable, so I could not inspect them on both sides, but the lenses looked quite a bit bigger than those on the Nikon, and a bit bigger than the ones in the Pentax as well. I’ll refer to this difference between eyepieces later again when I touch on eye relief.
I think I’ll skip the description of the packaging the scopes come in, since noone (including me) particularly cares what the box looks like. I will however note that the manual included a plot representative of the spectral profile of Optolyth’s Cerulin-Plus coatings. Since to get the spectral profiles of other coatings I typically have to dig through a bunch of patents (and even then most are hard to get), I really appreciated that. The plot below shows the reflectivity of one layer of Cerulin-Plus coating. An interesting aspect of this profile is the double-dipped shape. Apparently, the coatings were optimized for maximum transmission in the blue region (~420nm) and green-yellow region (~530-580nm). Whenever you see a company optimize their coatings for the blue colors, you know they were thinking about low light:
Here is another snapshot from the manual that shows the specs for the scopes:
There are two 25x70 models, I looked at the one leftmost in the table (BGA/WW). The XS model is almost identical except the eyepiece can be stored inside the spotter body for transport. I have never seen the 30x80 model. I do not think it is currently imported into US.
The 25x70 spotter has a field of view of 50m at 1000m (150ft at 1000 yards for the metrically challenged).
For comparison the field of view of the other spotters mentioned at the same magnification (25x) is as follows:
My observations at the range confirm the differences in the fields of view. One thing to note, however, is that all this field of view can be pretty hard to use if the eyepiece does not have enough eyerelief to show the full field of view:
I have tried to use all four scopes with glasses and without glasses (I normally wear contacts). The three scopes with variable eyepieces have adjustable p
Those who are merciful to the cruel, are cruel to the merciful. Talmud