Benchrest in Canada

Classifieds (Buy and Sell) => Optics => Topic started by: JimGnitecki on September 10, 2022, 03:21:42 PM

Title: What lens Rx for Varga lens? (REPOSTED in General Benchrest section)
Post by: JimGnitecki on September 10, 2022, 03:21:42 PM
REPOSTED in General Benchrest section

I wear eyeglasses with progressive lens. i.e. each lens has a lens that starts at the bottom of the lens with a Rx intended to facilitate "close distance" viewing (like reading books and computer screens), and gradually "progresses as you move upward on the lens to a RX intended to facilitate long distance viewing (like highway signs in the distance).

These eyeglasses do not work well when shooting a rifle with a 60 power scope, for a couple of reasons:

1. The eyeglass frame and lenses are physically too large, are in a non-adjustable position on my face, and are at an inappropriate angle when I a properly tucked into the rile / scope assembly. It is unnecessary, and muscle-stress creating work for me to stay in that posiiton, which naturally causes premature fatigue during the sighting process.

2. The "best" position that I finally get to is one that results in me looking through the uppermost lefthand side of the righthand lens, where I am actually seeing the left upper corner of the lens's frame, which means I have no choice but to use the long distance section of the lens, AND have the lens's frame as a constant distraction.

So, I bought a Varga frameset. That will enable me to basically put the lens almost anywhere in 3D space so that my right eye can look right through any portion of the lens that I choose to position right in front of my eye, and ot have the lens properly perpendicular to the ground.

The Varga lens holder accepts a 22mm diameter lens.

My local eye doctor at the local eyeglass place says the shop can grind and size the lens to fit the Varga, no problem. The eye dcotr is even willing to have me bring in my rifle (no magazine and no bolt of course), set me up on a table behind the shop, and use a device that lets him try different lens prescriptions in front of my eye while I look into the scope at the reticle and a distant object. (He is a military vet, so this is all cool to him)

However, I am thinking that his device might not physically fit between me and the rile, given the presence of the rifle stock.

So, I am wondering if it possible to instead simply grind a lens that matches my eyeglass Rx. The question is: what PORTION of the progressive lens should that Varga lens be ground to match? 22mm is too small a diameter to simply say "use the whole progressive range as found on the eyeglass lens." The resulting lens would transition SO much within a tiny fraciton of an inch as to make exact posiitoningsuper critical and even then, the actual size of the "ideal" portion of the lens might be too small.

I asked the eye doctor what prescription would be "right": the "distance portion" or the "reading portion"? He doesn't know anything about how adjustable focus and adjustable power rifle telescopes work, which is why he offered the "bring in the rifle" option.

I asked a good friend of mine who does F-Class shooting with the same types of scope I use, and he says that I should simply use the distant prescription, as the telescope adjustments take care of everything else.

Is he correct?

Jim G