Parallax
par•al•lax |’parə,laks|
noun
the effect whereby the position or direction of an object appears to differ when viewed
from different positions, e.g., through the viewfinder and the lens of a camera.
ORIGIN late 16th cent. (also in the general sense [fact of seeing wrongly] ): from French
parallaxe, from Greek parallaxis ‘a change,’ from parallassein ‘to alternate,’
based on allassein ‘to exchange’ (from allos ‘other’ ).
How does that affect Photography?
Parallax error can be seen when taking photos with many types of cameras, such as twin-lens reflex cameras and those including viewfinders (such as rangefinder cameras). In such cameras, the eye sees the subject through different optics (the viewfinder, or a second lens) than the one through which the photo is taken. As the viewfinder is often found above the lens of the camera, photos with parallax error are often slightly lower than intended, the classic example being the image of person with his or her head cropped off. This problem is addressed in single-lens reflex (SLR) cameras, in which the viewfinder sees through the same lens through which the photo is taken (with the aid of a movable mirror), thus avoiding parallax error.
If you have an old camera that is not a SLR camera, I hope this entices you to get a new one!
