PARALLAX ERROR Meaning and
Definition
-
Parallax error refers to the optical illusion that causes an apparent shift or misalignment in the position of an object when observed from different angles. It occurs due to the difference in perspective between the observer and the object being viewed.
In practical terms, parallax error is commonly associated with the inaccurate reading of measuring instruments or devices, such as rangefinders, telescopes, cameras, or even simple measuring tools like rulers. When the observer's eye is not aligned directly with the measuring scale or object being observed, an error can occur.
For instance, when using a rangefinder camera, the viewfinder is separate from the lens, which means the observer's eye sees the scene from a slightly different angle. This can result in misalignment when determining the exact focus point, leading to a blurred image.
In the context of measuring instruments, parallax error can lead to incorrect readings or measurements. When reading a scale or gauge, the observer must ensure that their eye is perpendicular to the scale, directly in line with the object being measured. If the observer's eye is off-angle, the position of the pointer or scale may appear shifted, resulting in an inaccurate reading.
To minimize parallax error, manufacturers often include features such as parallax correction controls or through-the-lens viewfinders. These adjustments help align the observer's eye with the measuring scale or object, reducing the potential for error. Additionally, proper technique and practice in aligning the eye perpendicular to the measuring scale are crucial to obtaining accurate measurements and readings while avoiding parallax errors.
Etymology of PARALLAX ERROR
The word "parallax" originates from the Greek word "parallaxis", meaning "alteration" or "change". In terms of astronomy, "parallax" refers to the apparent shift or change in the position of an object when viewed from different angles.
Likewise, "error" refers to a mistake or deviation from the expected or intended outcome. When combined, "parallax error" refers to the mistake that occurs due to the misjudgment of the apparent shift in the position of an object when viewed from different perspectives. In photography, this term is commonly used to describe the inaccurate alignment of the camera's viewfinder with the lens, resulting in a shift in the positioning of the subject in the final photograph.
