Nygord’s Notes on Iris and clip on lenses

Can someone help explain the “Champion” system that Mr. Nygord describes in his notes The Eyes Have It?  I count your basic lens (my regular prescription lenses, which I’m guessing are my ARS distance lenses, not Rx reading glasses or bifocals) on top of which there is a clip on lens of +0.25 to +0.50 diopters high is part of the system, then a separate iris as well?  Not sure I follow how it all works together.

Anyone have a picture? Is this still made?


http://www.cincinnatirevolverclub.net/nygordsnotes/eyes.htm

Reading the link it looks like he is talking about these:

CHAMPION SHOOTING GLASSES SYSTEMS (precision-sports.com)

Or Knobloch K5

https://www.knobloch-schiessbrillen.de/K5-Shooting-Glasses

Jim amd shenaba, thanks but I’m not seeing how those frames do this:

“This system uses clip-on lenses that can be quickly and easily put over the basic lens (usually a prescription lens to get your vision to "normal" or zero) to add power when needed. Then there is an adjustable iris or diaphragm that goes between the eye and the lens to allow changes in depth of field.”


He explains that in bright light, put a +0.5 clip on over your regular glasses.  In low light, put +0.25.  Then, I guess, put the iris on in low light?


“Plus lenses bring the focus in, minus lenses move the focus out. Generally, we recommend you start with two clip-on lenses: +.25 and +.50 diopter (diopter is one meter change in focal length). These take care of most situations. Here the rule is: "The stronger the light, the stronger the lens". So, in bright light you will need to add the +.50 instead of the +.25. Why? Depth of field.
Depth of field means over how long a distance things are things in focus. In bright light, your natural pupil closes down and you get the "pinhole camera" effect: everything for quite a ways out is in focus. This means the pistol shooter's no-no: the target will be in focus! We all know that you don't want that, so it takes an added power lens to "fuzz" it up again. Now what about low light? Well, when your natural pupil opens up everything gets "fuzzy" - most importantly, the front sight! And that is where the adjustable iris comes in: you close it until you get the sights sharp and leave the target "fuzzy".”


:thinking: