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eye relief question while moving through the powers

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03 July 2022, 04:43
perry
eye relief question while moving through the powers
I have a Leupold VX3HD 4.5-14x40. I mounted the scope and noticed that the eye relief flucuated from 14-4.5 and back, black edges. When set up for one power high or low, I would have to re-potion my head to get a clear field of view.
Is this normal with higher magnification scopes?
Most of my scopes are 2-10 so I have never noticed this.
It has the B&C reticle so I think it's pretty cool but I do not like the re-potion business.

Perry
03 July 2022, 10:03
sambarman338
This is quite usual with many variables and used to be much worse.

Some of the scopes 60 years ago could have, say, a five-inch eye relief at 1x but have it shorten to less than three inches at 4x. The greatest reduction could also happen at the low end, eg between 1x and 2x. My answer has been to set the eye relief somewhere in the middle and settle for a loss of FoV at some powers.

Some brands have almost fixed the problem now but often at the cost of the eye-box flexibility that let us do that.

With my mid-set eye relief, winding down to the lowest power could bring in that black ring or tunnel vision you mentioned but I notice on some my modern scopes it is worst on the higher powers.

Some brands are and have been happy to lie about these things in their specs, so check for yourself before buying.
07 July 2022, 07:01
BaxterB
With high magnification scopes, as you increase power, you decrease exit pupil, which makes eye relief critical.

With your x10 an a 40mm objective lens, you have a 4mm exit pupil,

your x14 with a 40mm objective has a 2.8mm exit pupil. In bright sunlight, your pupil will be about 3mm or so, meaning you have to be right inline with the exit pupil to get the clearest picture.
09 July 2022, 03:22
Stonecreek
Eye relief (optimal distance) has to vary with changes in magnification. This is just one of those irrefutable laws of physics. However, there are a few trade-offs (like making the sight picture smaller) which will minimize this phenomenon.

One of the unspoken problems (unspoken because it would put a damper on their sales) with the newer "wide variable" magnification scopes like a 3-18X is that the eye relief has to shrink a great deal when going from minimum to maximum power -- or the FOV will have to be very limited with poor "field blending" (sometimes referred to as tunnel vision).

What you want ideally in a scope is the largest "eye box" (both distance and offset from center) practical so that your eye can acquire the sight picture even when you are in a difficult shooting position.

Although their optics are among the very best, tight "eye boxes" and critical eye relief are the drawbacks most common with European scopes (not to mention their bulk and weight).
06 August 2022, 15:57
sambarman338
Stonecreek, you're feeding my paranoia about dislike of high-multiple variables.

But you might be on to something: a friend who knows about optics asserts that magnification is less done in the scope than by the angle light rays come into our eye. In order for light to come in at steeper angles the eye needs to be closer to the ocular.