ORIGINAL: Paul L Mohr
Cheif, that is how it is applied to graphics, but not optics. Resolution is simply how clear and detailed an image is. In a lens it is called angular resolution or the angular frequency. And when it is transferred to a flat plain it is called Optical Transfer Function.
There are cards and other devices available to test the resolution of magnified optics like scopes and binoculars. Usually it is just a bunch of lines you look at through the optics to determine how close together they can be and still be defined and not blur together.
The difference in clarity or resolution between a 50 dollar scope and 500 dollar scope can be pretty significant, Especially at higher powers and longer distances. It would also have to do with how well the scope would focus. Next time you go to a store compare a BSA Contender against a Zeis Conquest or even a higher priced scope. Look at something about 100 yards away on the same settings. If you can't tell a difference in the image you should have your eyes checked.
Another big issue is how much light the scope will transfer. That will depend on the quality of the lenses and what coatings are used on them and how well the tube is constructed (optically damped is what I call it, not sure if it's the correct term though.) Scopes don't "gather" light, they only transfer it and there is always some loss. They key is minimizing that loss.
Cheaper scopes usually don't have very good lenses or coatings so they are not as clear or transmit as much light. This means they will not be as "clear, crisp, and bright" as a more expensive scope. Do you need that to hunt with one. Not really, depends on what you are going to use it for. That doesn't mean it doesn't exist though. It sure is less strain on your eyes though. You really don't spend a whole lot of time looking through a rifle scope, unless you do a lot of bench shooting or something. Now the difference between cheap binoculars or spotting scopes is huge since you will be spending more time looking through them.
Paul
Pretty good Paul. You hit every point well.
You know whats sad is coating lenses is dog cheap. My company has this equipement and the intial cost is expensive. But once its setup, its very simple and cheap, but scope companies charge a fortune for it. But my company works on yeild. We coat thin film filters but have a very small yeild, but who cares, we have up to 1000 filters on one wafer we grow.With coatings you are trying to match the index of refraction with air so you have no loss of photons. I am still amazed how well lense companies are able to do this today. For us, we look at each filter (lense) individually and tweak as needed. These guys have a very good process for mass producing.
another thing, is those numbers like 95% transmistivity, is not the same from one enviroment to another. These numbers depend on humidy/air density, etc.