I've recently purchased the ZRS 8x42's and I've been putting them to use in the field and doing a little home novice testing. My basis for comparison is the Nikon Monarch 8x42.
Shortly after I received them (purchased from Doug at Cameraland for $205 and free shipping), I performed my home resolution test. Taping a draft of an email to my living room wall, poorly iluminated by a 40 watt lamp turned away from the email, then backing away along a tape measure. At 15' both binoculars were equal, same again at twenty feet where I had to hold each pair steady, concentrate hard and I could read one word at a time. At 22' I could not read any words with either binocular, but I could identify an occasional capitalized letter. Both binoculars were exactly the same. Well, I think pretty highly of my Nikon Monarchs, so that was impresive performance. I could not perceive an advantage for either in contrast, but the ZRS seemed sligtly better in brightness.
I moved the light further away, shaded it and concentrated on the books in one of my book shelves. With both binoculars I could read all the titles and the authors of both the Raymond Chandler's and the Dashiell Hammett's (paperbacks) on the upper two shelves and the color of the cover of Red Harvest was equally vivid in both binoculars.
The bottum shelf was very dimly illuminated but with the ZRS I could read the full title of "North American Raptors" and "Wheeler & Clark", while with the Monarch's I could only clearly read "Raptors". I guess dielectric coated prisms do work after all. The ZRS's were brighter in very, very dim lighting. Over all this is pretty impressive performance. I've tried my Nikon Monarch's against many other binoculars and only a few have equaled the Monarch's performance (Leupold Pinnacle 8x42, Vortex Viper 8x42 and ZR 7x36 ED2) and only one has shown better resolution (Vortex Viper 10x42).
For the last two weeks I've used both in the field. Neither has any significant advantage. Although the Monarch's rendition of colors is perhaps a bit more accurate. Red lettering on a white truck had a very slight purplish cast to it throught the ZRS's. The Monarch's were dead on when I walked up to the truck. Unfortunately, I can not see into deeper shade with the ZRS than I can with the Monarch. Of course the Monarch's handle better. They are the best handling full size (42mm) binocular that I've ever held.
One final thing, last weekend was bright and sunny. A parked van with a straight flat roof was reflecting sunlight along the line of the edge of the roof. Both binoculars when looking at this horizontal streak of reflected light through the center on the lens presented just the white light that was there; however, when looking through the lower portion of the lens the white light had a purple highlight below it and when looking through the upper portion of the lens a green highlight above the white light. This effect was a bit more noticable in the ZRS. But as I have not yet come accross any birds reflecting light in this manner, I do not consider this to be a negitive, just a curiosity.
I would have to agree with an earlier assessment of the ZRS 8x42 that I read here on Birdforum, as they are the equal (opticaly) of my Nikon Monarch 8x42's which are the equal of several pair of Vortex Viper 8x42's that I've tried (one pair extensively) and as things being equal to the same thing are equal to each other - the ZRS are about equal to Viper 8x42's.
These new ZRS's are a very good binocular. I'm keeping this pair. The only suggestion I would have is ditch the magnesium frames they weigh too much. Vipers weigh a 1/2 oz less with aluminum frames. The Monarch's of course have poly-carbonate frames which have many benefits, particularly in a salt water environment.
bearclawthedonut
