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Subject : Re: [Anaglyphs] Sticky Snow...Imre
From : "Imre dr.Zsolnai-Nagy"
To : anaglyphs(-at-)yahoogroups.com
Date : Mon, 7 Dec 2009 10:42:15 +0100
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Hi Mainer!
The SPM given disparity ratio is regarding the disparity and the horizontal image size.
If you use the 1/30 rule ( base/min. distance), only with 35 mm lens equivalent cameras you will have the disparity ratio 1/30 too.The same rule ( 1/30 rule, base/min. distance) with different focals, will produces different disparity ratio.
Reverse: to have every time the 1/30 disparity ratio, with different focal than 35 mm equivalent, you must use different shot rule regarding the base and min. distance.
I send some drawings, perhaps can help to understand something regarding the floating window too...:-)
Your shot (winter scene) is 250 mm base and near distance at 4000 mm, the used rule is 1/16 (base/near distance).
Theoretically you must have in SPM a 1/15 ratio. But you have only 1/25, because you dont have the real infinity on the scene.

Imre


2009/12/6 Mainer <jamcojam(-at-)yahoo.com>


As I recall, my cameras were about 10 inches apart and the nearest tree was about 12-14 feet away. Not zoomed at all. Twin Canon A560s. I assume that means 35mm.
 
I have a question. When using auto alignment in SPM, the result show a figure called "disparity of the infinity points". I always assumed that is the proportion of base to the distance to object. I usually get a good results when it is around 1/30. Again I always thought that is the same as 1:30 ratio. This shot resulted in 1/25, which is a bigger base than I usually use. It was intentional. When I saw the 1/25, I knew I would get more depth than usual.
 
Please excuse my ignorance, but I always kind of set the base instinctively. Any clarification regarding disparity of the infinity points will be welcomed.
 
Thanks
Mainer

--- On Sun, 12/6/09, Imre dr.Zsolnai-Nagy <imrezsolnainagy(-at-)gmail.com> wrote:

From: Imre dr.Zsolnai-Nagy <imrezsolnainagy(-at-)gmail.com>
Subject: Re: [Anaglyphs] Sticky Snow...
To: anaglyphs(-at-)yahoogroups.com
Date: Sunday, December 6, 2009, 2:33 PM

 
Excellent!
This is the time I must ask: what is the base and what is the focal?
( I bet for 9-10 cm base, 35 mm focal)

Imre

2009/12/6 Mainer <jamcojam(-at-)yahoo. com>


... this morning. Wish I hadn't caught the bush in the lower left corner. Cropping it would have taken the base of the trees.
 
Mainer






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