[rollei_list] Re: OT: Digital Projection
- From: John Wild <JWild@xxxxxxxxxxxxxxxxxxxxxx>
- To: "rollei_list@xxxxxxxxxxxxx" <rollei_list@xxxxxxxxxxxxx>
- Date: Wed, 21 Jul 2010 17:59:43 +0100
Eric,
I accept that 'rules' are there to be broken and are, but there are certain
limits, above which, some viewers may find the images uncomfortable. It is a
bit like not having transposed the two transparencies in a stereo pair; the
near and far points are thus transposed and this causes a mental 'struggle'
to try to correct what appears to be 'wrong' with the image.
I agree that the chosen divergence of the film (camera lenses) and the
viewing glasses is a criteria that different people cannot necessarily
accommodate because of the distance between their own eyes; but then changes
to the divergence does effect the apparent position of the near and far
points in relation to the window. This can also effect the apparent position
of infinity - whether it is in front of 'infinity' or as Buzz Lightyear said
"to infinity and beyond". For a still image the brain can adjust within a
few seconds; with a fast moving series of images, this is more of a problem.
I am no expert in this field but understand the basic principles - which I
picked up from this website - and from my attempts to produce and mount
stereo pairs, can see where I am going wrong. I am always happy to take
onboard more knowledge.
I have a roll film back for my Heidoscope. It is not a F&H one but was
probably made by an hobby engineer. It's well made and works just fine now -
I had to replace the light-trap because the old baize had fallen to pieces.
I have some photographs which I can dig out and sent to you if you like.
I get 6 pairs on a roll of 120 film. The images are sharp and well exposed.
The air-damper shutter is amazingly accurate for such an old camera. I have
an original plate back too, which is an 'interesting' design.
John
On 21/07/2010 15:34, "Eric Goldstein" <egoldste@xxxxxxxxx> wrote:
> John -
>
> I've worked in stereo for over 30 years and knows most of the folks
> who contribute content on the website you reference. Your explanation
> is not correct. Both those "rules" are not rules at all and can be
> broken comfortably in still and motion stereo imaging. It is done all the time
> and you can find examples which are widely distributed/published which
> most folks are happy to view.
>
> The likely cause of the discomfort you experience is your eye's
> inability to accommodate to the amount of divergence between the left
> and right image pairs the film-makers are offering you. Accommodation
> is highly individual and some folks can handle more than others. This
> is a well-documented problem with 3D imaging... some people simply
> cannot tolerate much of it and it strains their eyes and gives them a
> headache.
>
> As for Elias' screening appearing out of focus... it could in fact
> have been out of focus but we would need to know more before we could
> say so reliably.
>
> BTW do you have a roll film adapter for the Heidoscop?
>
>
> Eric Goldstein
>
> --
>
> On Wed, Jul 21, 2010 at 10:15 AM, John Wild
> <JWild@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>> Elias,
>>
>> I watched 'Avatar' in 3D and had to take my 3D glasses off in the early
>> scenes; later on I could put them back on again for a short time but then
>> had to take them off and on again. I started to feel 'sea sick' and my eyes
>> were starting to ache. A number of people also say this. As you say, it
>> 'appears' out of focus...
>>
>> Having played with my Heidoscope and 3D, I had researched the theories
>> behind 3D and when looking at the movie, two golden rules are broken which
>> cause the effect:
>>
>> i) the scene should be sharp from front to back. This did not happen with
>> Avatar because the director/cameraman wants you to focus on the 'talking'
>> actor (as in 2D) and so focus flits about and a large part of the screen is
>> blurred. Your brain cannot cope with correlating 3D and out of focus because
>> as your eyes flit about a 'live' scene, they automatically bring the centre
>> of vision into focus and do not 'see' the surrounding areas.
>>
>> ii) subject elements should remain within the stereo 'window'. It is OK for
>> a branch to come 'forward' through the window if it starts within the
>> window. It is not acceptable for this branch to appear in front of the
>> window if it appears to be coming through the area outside the window - this
>> can be caused by incorrectly spacing the two images. In Avatar, the tree
>> branches and the 'dust particles' appeared to be floating over the audience
>> and it seemed 'wrong' because some were outside the window. When the camera
>> flits about quickly, your senses cannot cope. I guess that the computer
>> operators over exaggerated the effect for the 'wow' factor; a bit like over
>> saturating a photograph to get the 'wow,' but it looks 'wrong' if over done.
>>
>> See - http://www.stereoscopy.com/library/waack-rules.html
>>
>> John
>>
>>
>> On 21/07/2010 01:47, "Elias_Roustom" <elroustom@xxxxxxxxx> wrote:
>>
>>> I watched Toy Story 3D today with my family, and it was great fun to
>>> see 3D animation.
>>> The whole picture was as far as I could make out, out of focus. I told
>>> the manager on my way out and she denied it (bitterly I might add).
>>> "It's all digital, there's no way it was out of focus." Hah. Brave
>>> new world.
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