parallax
Posted: Wed Nov 25, 2009 5:35 pm
In another thread relating to bandsaw bearing noise, the subject of parallax
came up.
I submit the following so as to enable anyone who does not know or understand what parallax is to hopefully understand it and recognize when it occurs.
Parallax occurs when the vantage point of the observer(or camera) is 'off to the side' of objects so as to give the appearance that the relative positions of the objects is different than they actually are.
This can be demonstrated by holding both your arms outstretched, hands together, point your finger at an object 6 or more feet from your finger. Then without moving your arms, shift your head left and right. The apparent position of the object will move away from the pointing finger.
The pix below demonstrate the effects when a camera is involved.
[ATTACH]6683[/ATTACH]
This was taken from just to the left of 'dead on' the bandsaw blade.
Notice the left face of the blade is visible.
Notice the blade appears to be close to the right end of the bearing.
Since the camera's flash is in line with the lens, all shadows are directly behind any object and therefore not visible in the pix. However you can see a reflection of the flash off the left face of the blade to the left of the blade.
[ATTACH]6684[/ATTACH]
This was taken from just to the right of 'dead on' the bandsaw blade.
Notice the Right face of the blade is visible.
Notice the blade appears to be closer to the left end of the bearing.
Although not as apparent as in the first pix, a reflection is to the right of the blade.
[ATTACH]6685[/ATTACH]
This was taken quite close to 'dead on'.
Notice neither side of the blade is visible.
Notice the blade appears nearer to the center of the bearing than either the right or left viewpoint.
The flash is above the lens so those objects higher or lower than the center of the pix do have a visible shadow(none to the left or right).
came up.
I submit the following so as to enable anyone who does not know or understand what parallax is to hopefully understand it and recognize when it occurs.
Parallax occurs when the vantage point of the observer(or camera) is 'off to the side' of objects so as to give the appearance that the relative positions of the objects is different than they actually are.
This can be demonstrated by holding both your arms outstretched, hands together, point your finger at an object 6 or more feet from your finger. Then without moving your arms, shift your head left and right. The apparent position of the object will move away from the pointing finger.
The pix below demonstrate the effects when a camera is involved.
[ATTACH]6683[/ATTACH]
This was taken from just to the left of 'dead on' the bandsaw blade.
Notice the left face of the blade is visible.
Notice the blade appears to be close to the right end of the bearing.
Since the camera's flash is in line with the lens, all shadows are directly behind any object and therefore not visible in the pix. However you can see a reflection of the flash off the left face of the blade to the left of the blade.
[ATTACH]6684[/ATTACH]
This was taken from just to the right of 'dead on' the bandsaw blade.
Notice the Right face of the blade is visible.
Notice the blade appears to be closer to the left end of the bearing.
Although not as apparent as in the first pix, a reflection is to the right of the blade.
[ATTACH]6685[/ATTACH]
This was taken quite close to 'dead on'.
Notice neither side of the blade is visible.
Notice the blade appears nearer to the center of the bearing than either the right or left viewpoint.
The flash is above the lens so those objects higher or lower than the center of the pix do have a visible shadow(none to the left or right).