Diopter correction on a RDS

[JiminAZ]

This is an old guy problem, but sooner or later all of you will face it. I am frustrated by inability to focus on the dot. I have used EOTechs and Aimpoint Pro, and both give me a blurry center dot.

Is there some practical, optical or engineering reason why manufacturers can not offer diopter correction on an RDS, or why the apparent focal distance of the dot is not further out?

Recently tried out an EOTech magnifier. Halleluiah! It's not the magnification, it's the diopter correction. I'd rather not have the magnifier but being able to see the dot and reticle clearly is a huge improvement for me.

I realize for the practical task of getting torso hits to 200 that I can probably live with it. Still, it seems like someone would have given us a solution to this problem by now.

[ptmccain]

Fwiw, the dot in a Trijicon RMR is very crisp and clear

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[JiminAZ]

ptmccain, do you need correction for near vision?

[Failure2Stop]

Have you tried flipping up your rear sight in conjunction with the RDS?

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[JiminAZ]

I like that idea. Aperture acts as a lens. Will try. Presume the best effect will be with the aperture located as close as possible to the eye, and that a small aperture will have more effect than a large one.

[markm]

In addition to the small app... are you turning the brightness down as much as possible.

[JiminAZ]

Yes, brightness reduction helps to a degree. I need about +2 diopter to read. Most of my optical scopes are near the limit of + adjustment.

[BillSWPA]

The problem with diopter correction is that it is dependent on the distance to the object on which you are focusing. Providing correction for the dot would seriously impair your ability to see through the scope. For target shooting this might not be a big deal, but I have concerns about it for target identification for more serious purposes.

Some smallbore rifle competitors will have corrective lenses manufactured to fit over the rear apertures of their peep sights. They bring their unloaded rifle in to their eye doctor, and he calculates the correction based on the distance between the front and rear sights.

I wear bifocals with nearsightedness correction on top, 1.5x magnification on the bottom, and a transition region in between. For a handgun, I get the clearest sight picture when looking through the transition region. Perhaps something similar will work for the red dot.

Looking through an empty aperture will sharpen up an image if your current glasses or contacts are not the right prescription, but not if your prescription is correct. If this helps, you should see your eye doctor for a revised prescription.

[JiminAZ]

Thanks Bill. I have progressives and if I align the correct portion of my progressive lens, I get a sharp dot and a clear target image. My prescription is recent and correct.

Here's where I'm having trouble understanding: given that either my glasses or the diopter correction on the magnifier yield a sharp image of both the target and the dot, why can't a manufacturer provide a diopter adjustment with no magnification on the RDS? In other words, insert the equivalent of my prescription between the RDS and my eye?

I can use my glasses at the range (although getting the right portion of the lens aligned requires some contortion). This just seems to me to be an easily rectified situation with the right product.

[JiminAZ]

The problem with diopter correction is that it is dependent on the distance to the object on which you are focusing.

Bill, this point that you make raises another question that you as an industry guy may know the answer to. Within an RDS, is the dot at a different optical distance than the target image? I would expect them to be the same or at least far enough away optically that diopter correction differences would be minimal.