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Discontinuous 3D effect (1 Viewer)

Ted Y.

Well-known member
Canada
My porro binocular has a good 3D effect, but if the distance in dept between 2 branches is short, the image of two branches is 2D. This is when both branches are at 30m from me. The minimum distance is ~15m.

Why is that?
"All" porro binoculars are like that?
 

WJC

Well-known member
My porro binocular has a good 3D effect, but if the distance in dept between 2 branches is short, the image of two branches is 2D. This is when both branches are at 30m from me. The minimum distance is ~15m.

Why is that?
"All" porro binoculars are like that?
Hi, Ted,

It has NOTHING to do with the type of binocular. I assume by “branches” you are referring to “barrels” or, more correctly, TELESCOPES. The 3-D “effect” is a product of looking at a target from TWO POINTS OF VIEW ... each telescope has a slightly different point of view. The farther the telescopes are separated, the greater the effect. At 30 feet, it can be great; at 200 yards it can be ZERO. I’ve worked on 27-foot rangefinders from a Navy cruiser. With those, you could just about see around trees at half a mile.
 

Ted Y.

Well-known member
Canada
I assume by “branches” you are referring
I will use different words.
If it is a short distance between objects (in depth direction), the image is 2D. Like the two branches.
If it is a large distance between objects (in depth direction), the image is so 3D.
The final image between 20m and 50m is a combination of 3D distant bushes and 2D for branches of a single bush.

“barrels” or, more correctly, TELESCOPES.
Agreed with "telescopes". Some people use "barrels",some people use "oculars"; this is the vocabulary in use. When in Rome ...
A few (other than you) use "telescopes", indeed.
 
Last edited:

WJC

Well-known member
I will use different words.
If it is a short distance between objects (in depth direction), the image is 2D. Like the two branches.
If it is a large distance between objects (in depth direction), the image is so 3D.
The final image between 20m and 50m is a combination of 3D distant bushes and 2D for branches of a single bush.


Agreed with "telescopes". Some people use "barrels",some people use "oculars"; this is the vocabulary in use. When in Rome ...
A few (other than you) use "telescopes", indeed.
"Oculars" should never be used in this situation.
 

jafritten

Well-known member
My porro binocular has a good 3D effect, but if the distance in dept between 2 branches is short, the image of two branches is 2D. This is when both branches are at 30m from me. The minimum distance is ~15m.

Why is that?
"All" porro binoculars are like that?
Ted, I know exactly what you mean. The 2D effect is brought about by what one may refer to as "telecompression": the distance (in depth) between two objects seems smaller than it really is. The higher the magnification the stronger the effect. The effect is there in every binocular and can also be observed in telephoto lenses. The image seems compressed. The 3D effect is brought about by the offset of the objective lenses, as explained by WJC in post #2.
When the distance between two objects is small (the branches, say 30cm in depth) telecompression works against the 3D effect. The 3D effect is more dominant when objects are farther apart (the trees, say 30m in depth).
 

Ted Y.

Well-known member
Canada
The effect is there in every binocular and can also be observed in telephoto lenses.
I observed the effect in a 10x roof prism binocular also. At shorter distance.
Telephoto lenses have this effect, even a 200mm (35mm camera) is clearly doing that. For this, I know the explanation.
 

jafritten

Well-known member
I observed the effect in a 10x roof prism binocular also. At shorter distance.
Telephoto lenses have this effect, even a 200mm (35mm camera) is clearly doing that. For this, I know the explanation.
I use a 500mm telephoto for wildlife and bird photography (see my gallery, if you like). What I can say is, that the effect seems to increase with distance and focal length. So, I think it possible that a lower magnification porro has a better 3D effect because the counteracting telecompression will be less pronounced. Also, the distance between the viewer and the object will have an effect, I suppose.
 
ZEISS. Discover the fascinating world of birds, and win a birding trip to Columbia
ZEISS. Discover the fascinating world of birds, and win a birding trip to Colombia
ZEISS. Discover the fascinating world of birds, and win a birding trip to Colombia

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