LOW LIGHT EVALUATION
@jwknutson17 and I had the chance to get out last week and do a quick review of these scopes in fading light. I have good news and I have bad news.
First the good news, all these scopes delivered like alpha scopes in low light.
The bad news, it has been a very wet summer in Colorado and as such the mosquitoes are on the rampage and we were fresh meat for their voracious appetite. As such, we were unable to conduct the full breadth of the evaluation which I usually like to do with a high and low contrast chart at 12x on each scope as the light fades from sunset to 30 minutes beyond.
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We had the Minox ZP5 3-15x50 and the Schmidt Ultra Short 3-20x50
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And of course we also had the Kahles K318i 3.5-18x50 and the ZCO ZC420 4-20x50
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CLARITY
Clarity can mean different things to different people, so let me define it here as the scopes' ability to produce an image that is detailed, a scope with good clarity is going to show detail throughout the sight picture and represent accurately the objects therein. Micro contrast is definitely going to play a role here especially with edge definition. In low light it's important for a scope to allow the shooters eye to differentiate between a branch or the tine of an antler. As mentioned above, the mosquitoes were crazy and swarming around us like flies on a dung heap, jwk brought a jacket but I was in short sleeves and they were relentless if we slowed to look through a scope. As such we could not keep steady long enough to do these scopes justice and we decided to just evaluate the best we could. At the end of the evening I made the comment it would have been fun to have had a video so you could all see are amazing dance moves as we tried to dodge the little bloodsuckers. Even though we could not stay still long enough for a thorough evaluation both jwk and I came away with the impression that all these scopes performed incredibly in low light. If there was one scope that struggled ever so slightly, both jwk and I agreed that the Schmidt Ultra Short showed the least amount of clarity within the image, this was seen in the lichen on the rocks behind the test target, the details in the lichen appeared sharper in the Minox, Kahles and ZCO than they did through the Schmidt which also aligns with my experience with two previous Ultra Shorts. Does this mean you should skip on the Ultra Short because it's a bad scope? Certainly not! We're talking the best of the best and to be at the bottom of the best (in one category) means you're still better than the rest, I would not pass up on the Schmidt Ultra Short if it meets all your other requirements for your type of shooting, you will be very pleased with this scope.
ILLUMINATION
We also conducted a quick illumination test and the scope with the brightest (by a considerable amount) illumination was the Kahles, cranked to full power the brightness in the fading late was almost too bright to look at, followed by the ZCO. I would be interested to see how the ZCO would do on it's own in bright sunlight (I should note that we only tested the red illumination and did not test the green illumination to see if that "appeared" any brighter to our eyes). Both the MR2 reticle in the ZP5 3-15 and the MSR reticle in the US 3-20 only have center crosshairs that light up with illumination, while the Schmidt did very well it seemed the ZP5 was a little brighter; would either of these scopes be daylight bright - highly doubtful, but very usable illumination when the light gets low and only having the center cross light up helps with identifying dead center for close up shots.
CONCLUSION
While I wish we didn't have to battle nature and could have spent more time conducting more thorough HC/LC testing, jwk and I both came away with the impression that all these scopes performed exceedingly well in low light.
On a side note, I've been looking for a new set of binoculars and rangefinders and had purchased a pair of Maven B.2's through Maven's demo program, I had the 11x45 and the 9x45 to compare to some Swarovski Swarovision EL 10x42's and I'll post an "initial impressions" in another thread in the "Observation Devices" forum, but a sneak peak is that we were both very surprised with the Maven's IQ.