Effect of lens spacing on 3D depth (example)

What difference does it make how far apart the camera lenses are and what does it look like? Well, as camera lenses are spaced farther apart it has the same effect as growing a bigger head. In the link below, you can see for yourself in 3D how the background and foreground stretch as the spacing between camera lenses increase and decrease. This link shows a cross view stereo pair. (about the only way to show 3D on a 2D computer monitor with any quality – and it is tricky to learn how to do)

To see it in 3D the trick is that you have to cross your eyes until the two red dots are merged (you perceive 3 images and look at the middle one). Lots of ways to learn how to do this, easiest is to hold your finger in front of you, look at your finger tip and move it towards the monitor and back towards your face. You should be able to see the red dots in your peripheral vision as you focus your eyes on your finger tip. The red dots will come closer together as you move your finger either towards your nose or towards the computer monitor. Once the red dots are aligned in your peripheral vision, then focus your eyes on the red dot and your brain should merge the two images into a single 3D image. As the image animates you see the effect of your head getting bigger and smaller. If you aren’t used to viewing cross view images it might take you a while to master it.  Don’t sit too close to the monitor or else you will be crossing your eyes a bit more than you would naturally want. For easiest viewing sit away from your monitor about twice as far as you normally would.


I’d like your comment on if you were able to see the above in 3D and what you noticed.



Filed under 3D Photography, 3D Video Monitors

10 responses to “Effect of lens spacing on 3D depth (example)

  1. very good.

    What is the max and min i.o. and what is the distance from lens to baby’s nose?


    Simon Sieverts

  2. Jim Huskey

    It took me a minute or two – had to “over-cross” my eyes a bit and then relax them. It was a little tricky to shift my gaze from my finger to the image of the baby, but once i got “onto” it, it looked eerily 3 dimensional. My eyes did feel a bit strained afterwards, and it took some effort to achieve the effect a second time as well. Interesting. I have never felt that kind of eyestrain while watching the new 3D films, though.

    • Crossing your eyes to view 3D is less than ideal but that is what we are limited to with computer monitors. I would never watch a movie this way and depending on how much you cross your eyes, you will feel about the same eyestrain as reading a book holding it close to your face. Certainly looking at something like this is a challenge as it is akin to expanding your head by over a factor of 10. Very unnatural, but the purpose was to show the effect in realtime of increasing eye spacing. the eerily 3D effect is due to going in and out of what you normally experience with your current eye spacing. Understanding the relationship of interocular spacing and viewing distance and size of screen is SUPER important and hopefully this little example demonstrates this importance.

  3. Sequence starts with 0″ then steps the interocular distance in increments of 2.5″ up to a max of 27.5″ Distance from lens at the above I.O. to baby is approximately 6 feet. The distance is interpolated as special optics were used to achieve 2.5″ interocular distance.

  4. Could you re-do this as a VIDEO on youtube for red and blue glasses (anaglyph) please.

    Please Email me when available. I am putting a video on 3D together for my http://www.cinetechgeek.com website and I would love an example like this.

    It is a topic we should be aware of but its very hard to describe. A video based on the above would be great.

    Or, if you like, make the original files available and I will see if I can do it over Christmas.


    • Anaglyph… ouch. I’m just really SO NOT a fan of anaglyph for many reasons not the least of which is the horrible trashing of the human eye rod receptors and the forced alien task of having the brain merge the resultant opposite color spectrum images into something that approaches a binocular image. Even with the best, highest optical quality anaglyph eyeglasses, anaglyph sucks IMHO. But throw in those abysmal cardboard things and I’m sorry but I’d rather look at something with my head immersed in a muddy creek.

      But how do I really feel?

      I’m not interested in participating in anything to do with anaglyph presentation. Do not use any of my materials or imagery for this purpose – I BEG you!

      This is going to be the year 2010 and please God can the ancient horrid tech of anaglyph please go away. It has NEVER been good. It has RUINED the image (literal and figurative) of 3D and made it a joke.

      Please RETHINK what you are doing and abandon anaglyph.

      Please. I beg you.

      Cross view is NOT a solution either. Many people can’t do it. But it doesn’t destroy the color and look like terrible-ness. And to put it on YouTube!

      Excuse me for a while as I must partake of a cocktail and calm down.

      • I am not a fan of it either but it is the ONLY easy way to represent any sort of 3D via a mass distribution system like youtube.

        The picture is not a demonstration of quality but effect. the effect can be seen in any form of 3D, even anaglyph. I don’t really care what is in the picture whatsoever.
        What are you trying to show here?
        A picture of a baby or the effect of having the distance between the lenses??

        If it is the effect of changing the ocular distance, then anaglyph will produce a better example.

        What exactly are you trying to show us????


      • The baby is not relevant of course, it is about showing the effect of interocular distance. We don’t agree that anaglyph will produce a better example, indeed I think anaglyph is perhaps the worst example of 3D that there is. It is high time that anaglyph is NOT the ONLY easy way to represent any sort of 3D via a mass distribution system. Why perpetuate a bad system just because it is the ONLY system? Loreo has a very inexpensive parallel viewer (www.loreo.com), some people can see cross view, but the best news of all is that in January at the Consumer Electronics Show there will be a myriad of 3D solutions for computers and gamers. The video is on the my server: http://www.2eyephotography.com/hyperbaby15fps.flv and the player is:

        the uncompressed AVI file is:

        While I still do not want you to use anaglyph, there isn’t anything I can do to stop you. If you use the above example I would appreciate a credit and a note that I do not prefer the use of anaglyph. Indeed, I am motivated to explain all of my reasoning in my next blog entry.

  5. msot computer monitors these days are already using LCD technology and some are LED-LCD .,*

    • Ok? Not sure what you mean by that. There are now (in 2010, note the orginial post was a year ago) several 3D monitor/glasses solutions but no universal compatible approach. Certainly, the vast majority do not have any kind of 3D viewing capability with their computer monitor – but we can hope that will change over the coming years.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s