Why So Hard To Focus Cross-Eyed?

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ElectroPulse
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Why So Hard To Focus Cross-Eyed?

Post by ElectroPulse »

Hello, all!

Lately I've occasionally been browsing around looking for side-by-side 3D images/videos to look at.

I have had parallel mastered for quite a few years (thankfully my dad had one of those 3D hidden image posters on his wall at his office, for whenever I was in there I'd stare at it, trying to see how far/close I could get to it, how much I could rotate my head and still view the 3D image, and how fast I could find it). One that I haven't quite gotten the hang of is cross-eyed 3D.

Cross-eyed 3D seems to be a lot less common than parallel... However, it seems that it has the most potential (my eyes can cross a lot more than they can go the opposite direction), so much more of my FoV can be filled with an image, and still be able to make two points converge.

My problem is getting the image into focus if it's more than 6-12 inches away... Any closer than that, and it's just a matter of 10-20 seconds of staring at it. However, the further away the image it is, the harder it gets. Are there any steps that can be taken to be able to do it better? (I'm guessing it's just practice, but am hoping there's some simple way of doing it.)

Thanks!

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Likay
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Re: Why So Hard To Focus Cross-Eyed?

Post by Likay »

I may be wrong but i think that some people have an easier time doing parallell viewing than crosseyed and vice versa. I can do both but i can on the other hand do crosseyed alot easier than parallell. To master parallell viewing small images (less size than my ipd) are needed and sometimes some shielding help with my hand. Crosseyed images can easily be viewed maximized on a 22" screen if the distance is 1/2 metre or more. The room isn't so big but 5 metres from the screen is not a problem either.
Afaik there's no other way to refine the technique than simply practice it.
When viewing parallell or crosseyed there is a process accommodation which probably is the cause of the problems to keep focus. The eyes and the brain had an entire lifetime to refine the accommodationprocess and that's not always easy to override.
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cybereality
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Re: Why So Hard To Focus Cross-Eyed?

Post by cybereality »

I find cross-eye to be a lot easier. For a while I couldn't do parallel at all, but now I can do both. Even so, cross-eye is a easier on larger images (even full screen) while parallel is only possible for me with small images. I guess everyone is a little different.

Fun fact: last time I checked, Neil wasn't able to free-view at all (correct me if I'm wrong).

Andyy
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Re: Why So Hard To Focus Cross-Eyed?

Post by Andyy »

Cross-viewing is more of a muscle that you need to learn how to flex. The strain initially experienced by a cross-viewer is the result of shifting attention.

When the eye is parallel free-viewing the fusion of the images is characterized by a smooth motion. On the other hand, Cross-viewing is more characterized by a 'twitch' in focus. I find before people can maintain a cross free view, they have sporadic moments when they 'SEE IT' and then loose it. I think people who struggle with cross viewing have anxiety when they experience the 'twitching' sensation--practice makes perfect and eventually it will become easier than parallel viewing (as it requires active focus).

My suggestion: practice free-viewing images with simple subjects. The more round the better, and the higher contrast, the easier it is for the perspectives to merge.

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ElectroPulse
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Re: Why So Hard To Focus Cross-Eyed?

Post by ElectroPulse »

Andyy wrote:Cross-viewing is more of a muscle that you need to learn how to flex. The strain initially experienced by a cross-viewer is the result of shifting attention.

When the eye is parallel free-viewing the fusion of the images is characterized by a smooth motion. On the other hand, Cross-viewing is more characterized by a 'twitch' in focus. I find before people can maintain a cross free view, they have sporadic moments when they 'SEE IT' and then loose it. I think people who struggle with cross viewing have anxiety when they experience the 'twitching' sensation--practice makes perfect and eventually it will become easier than parallel viewing (as it requires active focus).

My suggestion: practice free-viewing images with simple subjects. The more round the better, and the higher contrast, the easier it is for the perspectives to merge.

Image
Hey, thanks! I'll definitely practice with that image... Took me about 30 seconds to a minute the first time, then about 5-10 seconds the second time, then about 1-2 seconds the third time... Definitely a good one to learn on :)

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cadcoke5
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Re: Why So Hard To Focus Cross-Eyed?

Post by cadcoke5 »

I compare the challenge to that of learning to play chords on the piano. As a beginner, you have not yet learned to press the thumb, middle finger, and pinkie down at the same time, while leaving the other fingers up. While you have already learned to move the index finger independently of the others, normally the rest of the fingers are curled in at once.

Since you normally focus at a close distance when you have to cross your eyes, you have already learned to use those two groups of muscles together in a coordinated movement. It is also possible that God gave you some pre-designed brain wiring defined in your genetics to make this automatic. Going against this automatic behavior is probably more difficult than learning something like playing chords on a piano.

Another thing that may make this more difficult is that you don't normally change the focus of your lens in a deliberate manner. It normally just happens when you look at some. So, you have to learn to take control of something you don't normally control.

-Joe Dunfee

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