Improving the 3D viewing for a Sony HMZ T1 - PART ONE

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budda
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Improving the 3D viewing for a Sony HMZ T1 - PART ONE

Post by budda »

Hi,

I will be writing a multi-part thread describing improvements to the viewing of 3D images with the Sony HMZ T1.

These mods involve disassembly, removing parts and, permanently reconfiguring and altering the appearance of the headset.

This is a work in progress and may be revised at any time.


A number of steps will be described to achieve this.

They will be:


Step One - Bringing the eyepieces into the correct lateral position for the user viewing 3D images

This will entail the classic 'gear wheel mod' and the additional 'friction clamping mod'.


Step Two - Bringing the viewers eye closer to the viewing lenses.

This will entail modifying the front bulkhead of the headset to bring the users face forward into the correct eye box position.


Step Three - Bringing the correct depth of field for 3D viewing by use of modified prescription glasses.

This will require one pair of spectacles to be worn between the viewer and headset.


None of the modifications is necessarily related to ergonomics or comfort. That can be sorted out afterward.

It is the optical conformity with the user that is essential and will be exclusively looked at here.


STEP ONE Continued

The gear wheel mod removes the pinion wheel connecting the corresponding gear racks on the two eyepieces, so the eyepieces can be moved independently for optimum lateral eye box positioning.

The following online SONY HMZ T1 disassembly and gear wheel mod guide is recommended for viewing.

Sony HMZ-T1 disassembly by Izzy on YouTube - https://www.youtube.com/watch?v=rtno_wXG_aU

This is the video I first used when performing the gear wheel mod.


Following the gear wheel mod comes the friction clamping mod.

The friction clamping mod removes the cogging from the lateral spacing of the eyepieces and replaces it with an infinitely adjustable friction clamped spacing mechanism.

The friction clamping mod involves removing the two steel cantilever spring posts above the two sliding white plastic racks, then unscrewing and flipping upside down the white plastic racks, and then screwing the white plastic racks back in place.

By adjusting the overall tension of the four clamping screws on the sliding eyepiece rack, the level of clamping friction can be adjusted for each eyepiece.

The sliding tension of the eyepieces must be set before putting the casing back together, as the friction level cannot be adjusted outside of the casing.


The following photos show what I did to my Sony HMZ T1 in order to perform the gear wheel mod and friction clamping mod.
1.0 Sony HMZ T1 - internally modded with independent eyepiece spacing and friction locking slide adjustment.JPG
1.1 Sony HMZ T1 - topside cover removed.JPG
1.2 Sony HMZ T1 - front and lower face frames.JPG
1.3 Sony HMZ T1 - front face frame and eyepiece hanger with circuit board module.JPG
1.4 Sony HMZ T1 - existing rack and pinion eyepiece spacing assembly.JPG
1.5 Sony HMZ T1 - pinion removed and racks mounted upside down 1.JPG
1.6 Sony HMZ T1 - pinion removed and racks mounted upside down 2.JPG

PART TWO - modifying the front bulkhead of the headset - will be posted in another thread and will be linked from here.


Thanks.
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cybereality
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Re: Improving the 3D viewing for a Sony HMZ T1 - PART ONE

Post by cybereality »

Not sure why you're still using that old headset but I support this effort.

budda
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Re: Improving the 3D viewing for a Sony HMZ T1 - PART ONE

Post by budda »

Not sure why you're still using that old headset but I support this effort.
The Sony HMZ T1 contains advanced 720p OLED displays and it supports cinema quality visuals.

I am not sure if the current generation of headsets do 3D cinema very well at all.

The Sony HMZ T1 is HDMI plug and play compatible with Playstation 3 3D bluray, which means it is useful straight out of the box.

It was not intended for wide screen virtual reality but it is suitable for experimentation and research.

I got mine for 'parts and repair' but it fully works.

In my view the Sony HMZ was poorly designed and I am seeking to realise some of its hidden potential.

That said, it is really only for enthusiasts and masochistic 3D buffs.

Thanks.

budda
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Joined: Thu May 22, 2008 9:13 pm
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Re: Improving the 3D viewing for a Sony HMZ T1 - PART TWO

Post by budda »

Hi,


This article is the second in a multi-part thread describing improvements to the viewing of 3D images with the Sony HMZ T1.


STEP TWO Continued

Step Two describes modifications to the front bulkhead of the SONY HMZ T1 headset to bring the users face forward into the correct eye box position.


As it exists, the Sony HMZ T1 is designed to keep the users face at a suboptimal distance away from the images seen in the eyepieces.

The result is the central portion of the screens are somewhat in focus but the edges become progressively blurry and the overall image quality suffers greatly from what it should be.


Bringing the viewers eyes closer to the eyepieces is part of the answer in obtaining the best images for the user.

The Sony HMZ T1 is fortunately capable of having much of the front bulkhead removed for this mod without impacting on the structural integrity of the headset or interfering with its core functionality such as the optics, electronics or interface controls.


I have progressively and carefully whittled away the areas needed for placement of the forehead and nose in the headset with a mini hand drill grinder fitted with a rounded grinding tip.

There exists a secondary bulkhead at the front side, and a gear wheel bulkhead underneath which could be used as an extended support structure for the forehead and nose, in future.


As this is a work in progress I will likely completely carve away the front frame area between the eyepieces where the nose sits and put in an alternative support or padding for the nose.

I may even cut away some of the inside shrouding for the eyepiece as they touch the sides of my nose.


I advise caution on leaving edges and protrusions in and around the nose bridge and the eye brow and eye socket areas.

Pressure on these areas by wearing the modified headset can leave bruising and cause potentially damaging wrinkling in the soft tissue areas there.

Currently, I watch movies on the Sony HMZ in the horizontal and face-up position on the couch. To make it comfortable to wear for a couple of hours at a time, I use a thick and wide padded Band-Aid over the bridge area of my nose to prevent pressure injuries.


The purpose and extent of the carving so far has been to experiment and confirm the success of viewing the screens more closely.


The easiest sections to remove are the arch cavity in the top cover, and the lower nasal cavity between the eyepiece thumb sliders in the underside of the headset.

The middle central forehead, brow and nose cavity sections need to be more skilfully trimmed but there seems to be nothing critical to worry about apart from the exposed glass lenses, eyepiece cabling and some fastening screws.


I removed the head cushion support structure completely as its not needed anymore, and taped down the head activation switch. This switch can be also be enabled in the menu settings.


The appearance of carving out the front of the headset leads me to call this step the Darth Vader mod.

The following photos show what I did to my Sony HMZ T1 in order to perform the Darth Vader mod.
2.0 Sony HMZ T1 - frontal view 1.JPG
2.1 Sony HMZ T1 - frontal view 2.JPG
2.2 Sony HMZ T1 - underside view 1.JPG
2.3 Sony HMZ T1 - underside view 2.JPG
2.4 Sony HMZ T1 - underside view 3.JPG
2.5 Sony HMZ T1 - upper frontal view 1.JPG
2.6 Sony HMZ T1 - upper frontal view 2.JPG
2.7 Sony HMZ T1 - upper frontal view 3.JPG

PART THREE - use of modified prescription glasses for best viewing of the Sony HMZ T1 - will be be linked from here.


Thanks.
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budda
Sharp Eyed Eagle!
Posts: 383
Joined: Thu May 22, 2008 9:13 pm
Which stereoscopic 3D solution do you primarily use?: S-3D desktop monitor

Re: Improving the 3D viewing for a Sony HMZ T1 - PART THREE

Post by budda »

Hi,


This article is the third in a multi-part thread describing improvements to the viewing of 3D images with the Sony HMZ T1.


STEP THREE Continued

Step Three describes the use of modified prescription glasses for best viewing of the Sony HMZ T1, in conjunction with Step Two.


I discovered that my old reading glasses improved the clarity of the images seen in the Sony HMZ T1.

Those reading glasses have a lower strength than my current reading glasses.

So I wondered why those old reading glasses seemed to work so well, and what could be done to improve the image quality even more so.


The focal depth of the images in the Sony HMZ T1 seems to resemble the ripples of a water droplet on a pond.

To me it looks like a fourth order radial distortion affects the screen images.

Only a suitably configured light field camera could quantify the variation in image focal depth with some certainty.


In any case I was unsure if a suitable corrective lens could be used to produce an acceptable image across the full field of view.

It would seem if you brought one part of the image into better focus then another part would lose focus, so there would be no net benefit.


However, I investigated different prescription lenses and found a prescription that worked excellently.

This prescription should work similarly well for all Sony HMZ T1's made, and all users.

The only proviso to this bold claim is my Sony HMZ T1 is number '87 and I am not sure if any later improvements were made to the optics during the series production of this model.


I needed to establish a baseline for my distance vision, so I got an eye test and a set of spectacles made anyway.

Attachment 3.0 shows a picture of MY DISTANCE glasses prescription from a NIDEK LM 600 PD testing machine.

My distance focal depth is out by + 0.25 Dioptre and I have + 1 Dioptre of cylinder (astigmatism) at 90 degrees.

This is not great eyesight for 3D because my astigmatism double image runs horizontally and is more significant for blurriness than the distance focus is. However I see alright generally, but it is noticeable and detrimental for viewing in the headset.


I tried two more prescription glasses which had the distance power progressively increased in steps of +0.25 Dioptres.

I found the prescription glasses which had the +0.5 Dioptres added to MY DISTANCE glasses prescription were ideal.

Attachment 3.1 shows a picture of MY DISTANCE glasses prescription with +0.5 Dioptres added.


Anyone doing the prescription glasses mod for their Sony HMZ T1 needs to ADD 0.5 Dioptres to YOUR DISTANCE prescription.


It would seem short-sighted people may see the images in a Sony HMZ T1 better than people with long-sightedness.

This may explain why some people perceive the quality of images in the Sony HMZ T1 better than others do.


The glasses I obtained came from a budget 'Specsavers' line and I chose the 'Stig' model of glasses frame.


These frames are suitable for me because they allow the glasses to fit closely and comfortably to my face, and also to fit very closely between the headset and my face too.

They have a low brow line for fitting below the brow, a snug fit so there is no gap between the glasses and nose, and a single bar that bridges my nose.


For people with a larger nose bridge that prevent the glasses sitting close to the eyes, they may either need a curved bar around the nose bridge, or they may have to cut out the bridge bar from their glasses and mount them directly on the headset.


I haven't worried about coatings on the glasses to supress internal reflections at this time. This feature is usually an expensive extra and I am not certain it's really a problem worth spending money on.

There is also a potential option to add prism to the lenses for convergence reasons should the need arise.


The following photos show what I did to my Sony HMZ T1 in order to perform the prescription glasses mod.

3.0 MY distance spectacle prescription for everyday distance viewing.JPG
3.1 MY modified spectacle prescription for Sony HMZ T1 is MY Distance spectacle prescription Plus 0.5 Dioptre.JPG
3.2 Prescription spectacles for Sony HMZ T1 - front view.JPG
3.3 Prescription spectacles for Sony HMZ T1 - plan view.JPG
3.4 Prescription spectacles for Sony HMZ T1 - general view.JPG
3.5 Budget SPECSAVERS brand STIG model year 2017 - product code 30397866 - front view.jpg
3.6 Budget SPECSAVERS brand STIG model year 2017 - Product code 30397866 - general view.jpg
3.7 Prescription spectacles superimposed on Sony HMZ T1 - straight on front view.JPG
3.8 Prescription spectacles superimposed on Sony HMZ T1 - low side front view.JPG

Thanks.
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