Monday, September 10, 2012

Part 2 - Sitting Too Close To Your 3D TV Will Make You Blind?

In Part 1 of Sitting Too Close To Your 3D TV Will Make You Blind?, I make the point that no two people perceive 3D in quite the same way and that efforts to standardize proper viewing distances from 3D display devices should take this into account.  Indeed, what you consider to be a comfortable viewing distance from a 3D TV or movie screen might be totally different than what I consider to be a comfortable viewing distance.  Part of the reason for this difference is the relative visual acuity of our eyes, the balance of that acuity between our two eyes and the ability of our extra-ocular muscles to control our gaze such that reflections of the outside world fall properly on the retina of each eye.  The important thing to remember is that everyone’s eyes are different and very few people have eyes that are perfectly balanced for binocular vision.

An Extreme Case In Point

In my Blog How Hugo Gave OneNeuroscientist The Gift of Stereo Vision I introduce Dr. Bruce Bridgeman, a scientist who lived in a 2D world all his life because he suffered from a form of strabismus called exotropia, where his extra-ocular muscles are not properly aligned, causing each or one of his eyes to point away from his nose.  This condition made it almost impossible for Bruce to align his eyes such that his binocular field of view was similar enough for his brain to fuse them into 3D.  Instead, he tended to use his stronger eye to see and his brain would, in effect, turn off the images registered in the other, weaker eye.  With only one eye used for seeing, Bruce was essentially stereo blind… he could not see 3D.  That is, until he miraculously experienced 3D for the first time while watching Hugo in a 3D theater.  His description of that life-changing moment is well worth the read. 

I believe the miracle Bruce experienced during Hugo can be explained by two factors.  One factor was the degree of depth and volume that Scorsese so masterfully created in his first 3D feature film, coupled with the fact that Bruce was sitting approximately 65 ft. from the screen. Sitting at that distance from the screen, Bruce simply had to set his eyes at infinity, or in other words during the entire movie he had to line up his eyes in parallel to each other while looking at the screen. Had he been sitting at the recommended 1.5X of the screen height for “optimal viewing comfort” it would have created an insurmountable challenge for Bruce because he would have had to constantly adjust the convergence of his eyes.  The lesson here is that if you or anyone you know has a problem with watching 3D movies comfortably try sitting much further back in the theater.  It should not diminish the experience and will most likely make the movie much more enjoyable.

One Person's Immersion is Another Person's Headache?

In addition to individual preferences for comfortable seating in a 3D theater, there are some people who have very different definitions of what is meant by stereo immersion. This became most evident to me at the 38th National Stereoscopic Association conference that I attended two months ago.  In fact, it was that experience that prompted me to write this two-part blog.

Just about everyone I met at the conference was extremely knowledgeable about the craft of stereo photography and of stereo in general.  For the most part, the attendees were collectors of stereoscopic vintage cards and stereographic hobbyists.  It was a pleasure talking with them during the one day I was there because they were probably the most knowledgeable audience and certainly the most enthusiastic I’ve ever addressed on the topic of 3D. 

At the conference there were several art exhibits of anaglyph images, some framed, some not.  Most were creatively appealing. The experience was very interesting and enjoyable.

But it was in the big 3D theater that I experienced a unique perspective on stereo that I was not expecting. Most of the afternoon was devoted to stereo photographers exhibiting slide show montages of their stereographs on the big screen. My team and I thought the presentations were for the most part innovative and entertaining.  However, we also noticed some things that seemed unusual to us.  The obvious thing was that many in the audience were crammed up as close to the theater screen as possible. 

That seemed odd because most colleagues in the movie industry tend to view 3D content considerably further back from the screen.  Furthermore, from where we were sitting, around mid-theater, the projected images appeared to have hyper-stereo depth that was unrealistic to our eyes and in some cases uncomfortable. It was as if the photographers purposely increased the inter-axial separation between the lenses of their cameras to create an exaggerated 3D effect.

According to one of the organizers of the event, this is how the attendees prefer to view their work. They sit as close to the theater screen as possible so that they can achieve a field of view that encompasses the entire screen.  They are looking for total immersion in each stereograph and sitting close to the screen somehow gives them that experience. The organizer went on to tell me that the attendees sitting up in front were very experienced at decoupling accommodation and convergence so that they could view the hyper-stereo images close to the screen without getting sick or tired. I tried viewing the slides from the front seat of the theater and could not handle it for any length of time.

Following My Presentation The Stereo Perspective Of The Group Became Clear

That evening in the theater I presented a colorized and converted 3D clip from Harold Lloyd’s comedy classic, Safety Last as well as some of Legend3D’s most recent tent-pole feature film conversion work.

Prior to my presentation, a good friend, Suzanne Lloyd, granddaughter of famed silent actor and stereo enthusiast, Harold Lloyd, exhibited a selection of landscape images from the hundreds of thousands of stereographs that Harold took during his later years in Hollywood.  They were nothing short of stunning.  His sense of depth and composition was masterful.  In contrast to the montage exhibits that I saw earlier in the day, Harold’s work was obviously adjusted for the big screen and looked natural to me in every part of the auditorium.

An Audience Member’s Question

During the Q&A period of my presentation, one audience member asked me whether Legend3D adjusts the disparity of feature films we work on to fit the size of the display.  That is, he wanted to know if we increase the disparity and hence the 3D volume of a feature film that is going to smaller screens like Blu-ray for 3DTV viewing.  The thought is that the amount of disparity created for the big screen will appear considerably smaller for the small screen.  Consequently, the footage requires adjustment so it is comparable to the theatrical experience.

I explained that we don’t make those adjustments and it’s unlikely that the studios would want to create multiple versions for every size screen available.  I am aware of stereographers at some of the major studios who sometimes adjust the convergence of selected shots to reduce ghosting, which can occur in 3DTVs, particularly where there is significant contrast in the image.  However, the disparity of most 3D Blu-ray released feature films is identical to what was originally seen in the theater.  I went on to explain that at legend3D we design our conversion for the big screen and that everything I screened in the theater during my presentation could be viewed comfortably and with sufficient depth on a 3DTV of any size and even on a 3D computer, tablet or cell phone.

For Movies, You Can Go Down But You Can’t Go Up

I went on to tell him that in 3D moviemaking the disparity created for the big screen typically works for smaller screens without any adjustment but you can’t always take footage with disparity created for a cell phone or even a 3DTV and scale it up for the big screen without an adjustment.  It would simply appear hyper-stereo with exaggerated volume to the point of appearing distorted.  And while watching a stereographic slide show as close to the screen as possible might work for certain groups; watching a whole movie like that would give a brain ache to the most die-hard 3D enthusiast.

The Audience Member’s Follow-Up Challenge

After my presentation the same audience member came up to me to discuss the issue in greater depth.  He told me that he got rid of his Panasonic 3DTV because every Blu-ray he bought looked flat.  I told him that every Blu-ray of a properly shot and/or converted movie that I’ve screened on my 55’ LG looks outstanding.  But to satisfy the guy, I told him that I’d show him some of the footage from my presentation on the big screen, but this time I’d show it on my 3D laptop and my 3’ Evo3D cell phone.  I started by showing him Legend3D’s Spiderman conversion work on my Acer 15’ 3D laptop. The guy immediately put his head nine inches from the screen blocking my view and remarked, “Just as I thought, it looks flat.”  The guy was crammed up close to the laptop, the same as the audience was crammed up to the theater screen earlier in the day.  I told him that the way he was watching the 3D on my laptop was not at the proper distance.  I pulled him back approximately three feet from the screen where it looked great to me and I told him the farther he moved from the screen the greater disparity he would perceive.  I went on to tell him that he should find a distance that was comfortable for him, but certainly not with his nose touching the screen.

By that time, I fully understood his issue, which related directly to the way people were screening the stereo montages earlier in the day.  He responded defiantly with what was then an anticipated perspective.  He said that he wanted precisely the same immersive experience on the laptop that he had in the theater and that meant achieving the same field of view of the laptop screen as he had in the theater.  After that comment, I couldn’t resist showing him the Spiderman conversion on my cell phone.  Yes, he held the cell phone approximately three inches from his face and to him it was indeed flat. 

As with the laptop, I told him that he needed to move the phone away from his eyes and he should see greater depth and negative disparity (in front of the screen). It became clear that there was no convincing that guy that a laptop and a cell phone represent a different viewing experience than a theatrical screening.  Nope - this group, for the most part seems to be looking for a totally immersive experience where the optimal field of view is the full extent of the screen.  They apparently expect an IMAX experience from a 15-foot projection screen, a 55-inch TV screen, a 15 inch lap top and a 3-inch cell phone.

Is this wrong?  It’s absolutely not wrong if that’s the kind of experience they are looking for, but they can’t expect to achieve the same degree of stereo as when they are sitting at comfortable distance from the screen.  I can certainly understand how 3D enthusiasts might want to view single stereo frames up close and personal but I would assume that there are few people who could watch an entire movie that way. 

The Bottom Line

There are at least two ways to accommodate different screen sizes.  One way is to modify the disparity of the 3D to match the screen size.  This is impractical for several reasons not the least of which is the cost of creating many different versions of a movie to fit a plethora of TV and cell phone screen sizes.  The second way is to view the various screen sizes at distances that deliver a form of immersion but via an experience that is clearly different from the theatrical experience.  In other words, if you reduce your viewing angle of the TV, laptop, tablet and/or cell phone you’ll likely get a proper 3D experience that suits you.  I imagine there are some directors who might find it unsettling to know that portions of their audience are not experiencing their films in the manner that they intended them to be seen.  However, based on what I saw at the 38th National Stereographic Society conference, it appears that some people put a substantial personal spin on their 3D experience.  That personal spin can involve special seating distances from the screen because of vision issues and/or it can involve special seating distances that influence the type and quality of the 3D experience the person is attempting to achieve.