Types of Focus

[vin]

AKA Types of Blur

I have been examining the different types of blur that I experience during my training.

I am 20/15 with both eyes open and I use an iris (sharpie circle on my safety glasses) and a large occluder (tape on the other lens, all the way to the bridge of the nose).

Haze Blur:
Yellow haze drapes over the left OR right of the front sight. Happens when I don’t use a iris.

Diffraction Blur:
Diffraction lines on the left, right, and top of the front sights. Diffraction lines on the left and right of the rear sight. Happens after my eyes get tired (twenty to thirty shots). Happens because my eyes converge. Happens sooner if the occluder does not go the bridge of my nose. Goes away when I “right eye" real hard, which makes me very tired.

Soft Focus Blur:
Both sights soft focused. Happens after my eyes get tired (twenty to thirty shots). Happens because my eyes converge. Happens sooner if the occluder does not go the bridge of my nose. Happens because it gets harder to focus on the front sights as training goes on. Goes away when I force the focus to the front sight, but this gets harder as training goes on.

Whiteout Blur:
The front sight seems dimmer than the rear. The front sight may whiteout on one side more than the other. Happens when I use plus one diopter lens or a tinted lens. Important- does not seem to negatively effect my score until it gets really bad OR the light conditions are lower than my home range (the range I compete at seems to have lower light conditions). My eyes tire slower, but it feels weird having the white on the front sight.

Blackout Blur:
Gap between front and rear sight is too dark to meter. Happens when my eye is not in the right place. I usually have to rotate my head to the left, which seems weird. Also happens when the iris is not perfectly centered.

Please advise on how I can “right eye focus” better/longer at the competition range which has less light than my home range.

Thanks,
Vin

[RobStubbs]

Vin,
How wide is your rearsight - i.e. how big is the gap ? If the notches are too small then that can induce blurring aound the edges and no doubt other optical effects. I personally use a very wide rear notch but the general recommendation is that the white notches should be at least 50% of the width of the foresight. That white notches size should also be similar to the white gap between foresight and bull (in a sub-6 hold).

Rob.

[RobinC]

Vin
An interesting analysis, I would concur with Rob on rearsight, I have always used "big" sights out of preference but now with advancing years find it even more important and use the biggest foresight and have set about the rearsight on my pistols with a swiss file.
I also used an iris for many years but have found that there is less blur with out the iris.
Your analysis is really interesting, I had 20/20 for most of my early shooting life and never even thought about eyesight, now at over 60 its a vital element in maintaining a shooting standard, a good optician who understands pistol shooting can be a great help.
Best of luck
Robin

[vin]

Thanks for the replies.

My rear notch is as wide as I can get it on the Benelli Kite Young.
But it is not wide enough so that the gap is half the width of the front sight.
I've looked for replacement front sights without any luck...

Vin

[Tolkach]

I recently took a sports medicine course as part of formal training for coaching. One interesting thing they pointed out is that your vision will begin to blur with minor dehydration. When I shoot, I try to stay hydrated throughout the day and will carry a bottle of water to see me through the match and my eyes don't blur as quickly.

Just one more thing that may help reduce some of the blurring, or at least delay it.

[RobinC]

Thanks for the replies.

My rear notch is as wide as I can get it on the Benelli Kite Young.
But it is not wide enough so that the gap is half the width of the front sight.
I've looked for replacement front sights without any luck...

Vin

Vin
That's why I bought a set of swiss files and opened mine out, I use a Steyr LP2 compact which should be similar to the Kite Junior, with a front sight 4.5mm (as big as I can get) and the back filed out to 5.0mm. It horifies others when they look through my sights but they soon get bitten by the big bug.
I also use shooting glasses with a monocle lens for the shooting eye with the focus set at the focal length of the forsight.
Best regards
Robin

[vin]

File my adjustable sights?
Not sure I have the nerve for that!

[vin]

My friend William just pointed out that the diffraction lines are most likely due to focusing on the rear sights.

I do seem to focus on the rear sights when my ayes get tired...

[RobStubbs]

File my adjustable sights?
Not sure I have the nerve for that!

Don't worry about it, you can't really do any damage. And hey if you did, then you'd just need to buy a new one. The most important thing is that the gun fits you and that the sights are set for you. If you need tools to acheive that then so be it.

If your eyes drift to the rearsight when tired, that suggests your prescription is wrong and that you're 'forcing' your focus onto the foresight.

Rob.

[vin]

I guess I better find my small files...

I'm definitely forcing my focus!
My hand and the target are easy to focus on, but the front sight takes effort.
I started using a one diopter lens on 16MAR10 and that seems to help a lot.

Thanks,
Vin

[vin]

Yesterday I did not read or use the computer.
I used a 1 diopter lens as usual and practice went very badly.
I could not get the bull to blur as usual.

My next competition will be in the morning and my eyes will be well rested.
Maybe I will need a higher diopter?

Thanks,
Vin

[PETE S]

I concur with Tolkach on hydration. One reason for vision blurring is the cornea getting dry. Blinking will help. Some shooters stare endlessly at their sights without allowing blinking. By blinking, you allow the cornea to hydrate. You may just have to relax a bit!

And whilst you may be 20/15, are you of the age when many of us need reading glasses? Holding a book or other normal reading distances are closer than your front sight so you actually need less correction than for reading a book.

Third and controversial is that the blurring is because you are not really focused on the front sight. You are paying attention to some extent, so you notice the blurring. But the focus may be else where. I get the impression that many shooters make it to the development team stage and then learn to focus on and pay attention to the front sight.

I know from my own experience that the sights can be very difficult to focus on and pay attention to. I see blurs etc and think I am seeing the sights. Results on the target are marginal. Then I really work harder on the focus and get the sights big and black. Results on the target are much, much better.

[Raymond Odle]

I have spent the bucks for the shooting glasses, adjustable iris, lenses, etc. but at 59 yrs old I not so sure that just a $10.00 pair of reading glasses are better. At least I can see the pellet to load it the right direction.

[joker]

I have spent the bucks for the shooting glasses, adjustable iris, lenses, etc. but at 59 yrs old I not so sure that just a $10.00 pair of reading glasses are better. At least I can see the pellet to load it the right direction.

At 69 years of age I know very well what you mean - I resurrected an old pair of middle distance specs which I am using at moment - I hesitate to spend more money on anything else until I am assured a benefit and I cannot demonstrate any benefit 'till I spend more money - hence impasse.

[David Levene]

.......I hesitate to spend more money on anything else until I am assured a benefit and I cannot demonstrate any benefit 'till I spend more money - hence impasse.

Catch 22.

You cannot know the benefits of a properly prescribed and set up set of shooting glasses until you take the plunge.

When I first invested in a set of Champions from an experience shooting optician I could not believe how clear and sharp the sights were.

At the time (28 years ago) it was achieved with just +0.25 dioptres on top of my normal glasses (it's now =0.5 dioptres). I am convinced that an equal share of the improvement came from the fact that I was able to look squarely through the centre of the lens.

[Retired]

If you use a full diapter and you tend to focus on the rear sight when your eyes are fatigued, you might try a less powerful lens, let's say .5 or .25.

I have been 20/15 most of my life and I started with .25, eventually went to .5 between my first and second Olympics, then finally switched to .75.

As soon as you reach 40, your eyes will have a difficult time focusing between close and far points. At least that's the what most people experience.

All the others are correct, too. Width of notch, width of front sight, dehydration, fatigue... they all play a factor.

Good luck.

Retired

[vin]

As Retired suggests, I will try changing diopter and try to understand the results from the changes. Seems like something I should have done sooner...

BTW, blinking seems to snap my focus to the front sight sometimes- very cool.

Thanks!
Vin

[vin]

*At home:
With the .62 diopter lens I no longer seem to get tired and...
I can now tell the difference between "ten ring" capable focus and "nine ring" capable focus.
Two things have happen because of the differentiation. I abort a lot more often and then after too many aborts I jerk the trigger when the focus is "ten".

*At the match (lower light?):
I can't get sharp focus unless I close the left eye!!! :(
Then I get tired closing my left eye and I have to shoot with both eyes open again.

[Spencer]

*At home:
With the .62 diopter lens I no longer seem to get tired and...
I can now tell the difference between "ten ring" capable focus and "nine ring" capable focus.
Two things have happen because of the differentiation. I abort a lot more often and then after too many aborts I jerk the trigger when the focus is "ten".

*At the match (lower light?):
I can't get sharp focus unless I close the left eye!!! :(
Then I get tired closing my left eye and I have to shoot with both eyes open again.

use some form of translucent (not opaque) occluder on the non-shooting eye

[vin]

I do use an occluder, but at the match I still had to close my left eye to get good focus... :(