Understanding The Graphs In HAM’s Scope Reviews
Hard Air Magazine is now publishing the best scope reviews you’ll find anywhere!
For the first time, HAM riflescope reviews include had data about the optical performance of the scopes we test. Unlike all other scope reviews, we don’t just say “We think it’s sharp” – WE PROVE IT!!!
This data comes from professional testing by Trioptics – a world leader in optical testing and test equipment. Trioptics professionals use their amazingly-precise ImageMaster system to measure the optical performance of each riflescope.
The Trioptics system produces a huge amount of data as it makes these measurements. To aid understanding, this data is also used to generate graphs. These graphs are what we are showing in HAM scope reviews.
But how do I understand these graphs? It’s really easy if you follow along with these instructions…
Resolution And Contrast
For HAM, Trioptics measures resolution and contrast. They do this at three different magnifications: the maximum and minimum for each scope, plus at a marked 9 X magnification.
But what are resolution and contrast?
Resolution is the ability of a scope to let you see detail. So a low resolution scope only allows you to see big things. A high resolution scope lets you see very small subjects.
The Trioptics graphs in HAM scope reviews show resolution on the horizontal (x) axis. It’s called “Spatial Frequency” on the chart itself. Like this…
The other (y) axis of these charts indicates contrast. High contrast is the difference between perfect black and sparkling white. Low contrast gives a mushy “grayness”. You’ll probably have seen this with poor quality scopes as the image “washes out”.
Great Optical Performance
The black line indicates theoretically perfect performance. There’s also a solid red line and a dotted red line. These represent the actual performance in horizontal and vertical directions (see below). The closer the red lines are to the black line, the higher the contrast at the corresponding resolution.
Poor Optical Performance – Contrast
If all riflescopes performed perfectly in HAM scope reviews, that’s what you would see every time. But, of course, life is not like that and – in practice – scopes will exhibit less than perfect performance.
The Trioptics graphs show poor performance by a gap between the black (theoretically perfect) line and the red lines.
The bigger the gap between the black line and the red lines, the worse the quality. So, poor contrast looks like this…
Poor Optical Performance – Blurring
The Trioptics system makes measurements in two directions. These are known technically as tangential and saggital. If we imagine a series of vertical lines, that’s tangential. Horizontal lines are saggital.
These measurements are represented on out graphs by solid and dotted red lines.
If both red lines are on top of each other (or very close) this tells us that the scope’s image is equal both horizontally and vertically. So, if we are looking at a tiny point of light, it looks perfectly round.
The bigger the difference between the two red lines, the less uniform the scope’s optical performance. So, when looking at that tiny point of light, we see an ellipse instead. The bigger the gap between the red lines, the more elliptical the circle looks through the scope. That’s showing that the scope is blurry!
The bigger the gap between the red lines the blurrier the scope. Oops!
But Wait, There’s More…
So now we can see how easy it is to have a real, objective view of a riflescope’s optical performance. And it’s only here in HAM scope reviews.
Of course, sheer optical quality is just one component of a good scope. But it’s a VERY important one, of course!
However, you’ll also find some more key information beyond these optical quality graphs.
The Trioptics system also measures a scope’s magnification. That enables us to understand if a – say – 4-16X scope actually does give you magnifications between 4X and 16X. Often it does not!
So, if you set 12X on your scope for example, that may not actually be the magnification the scope delivers to you. Field Target shooters take note!!!
HAM scope reviews give results for three different magnifications: the maximum and minimum for each scope, plus at a marked 9 X magnification.
HAM scope reviews also measure the accuracy of the riflescope’s range markings. When you rotate the AO ring and see that it reads 30 yards, is that really 30 Yards?
If it’s not correct, your holdover will probably be wrong and you could miss the target. Again, you’ll find the scope’s range-indicating accuracy highlighted in every review. And more.
Enjoy reading our scope reviews. I hope they will be useful and informative!