Photography – With viewfinder – Parallax correction
Reexamination Certificate
2002-01-23
2003-11-11
Adams, Russell (Department: 2851)
Photography
With viewfinder
Parallax correction
C396S084000
Reexamination Certificate
active
06647207
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of cameras and, more particularly, to a parallax compensation system for a camera.
BACKGROUND OF THE INVENTION
Cameras having non-through the lens viewfinders, that is, viewfinders with an optical axis distanced from the image capture optical axis, exhibit a problem with parallax error at close shooting distances. At normal shooting distances (1.5 m to infinity) the parallax error is negligible. However, at very close shooting distances (i.e. 0.25 m), the parallax error causes unacceptable aiming mistakes. There are several existing methods to address this problem: 1) ignore it for very low-end cameras and simply accept aiming errors; 2) add so-called parallax markings in the bright frame mask, which require the user to remember to use those markings to recompose the subject if it is at close distance; 3) use a bright frame viewfinder with parallax markings and control the visibility of those markings automatically with moving masks or with liquid crystal panels; 4) employ an elaborate mechanism to couple the viewfinder mask or bright frame to the focusing movement of the lens, which mechanism typically comprises cams and levers and even motors in some high-end cameras.
A number of patents have tried different means for addressing the parallax error in cameras at close shooting distances. U.S. Pat. No. 6,243,539 to Chen provides a parallax compensation apparatus for a camera which comprises a viewfinder pivotally connected to a camera for locating objects to be taken. A follower link connected to the camera and having one end pivotally connected to the viewfinder causes the viewfinder to pivot, moving the adjusting device such that the optical axis of the viewfinder meets the optical axis of the lens in the subject to be taken.
U.S. Pat. No. 4,924,247 to Suzuki et al., relates to an apparatus and method for correcting and adjusting parallax in an electronic camera. Suzuki provides a parallax correcting apparatus which comprises an imaging device driving mechanism for supporting and moving an imaging device away from and towards the optical axis of the finder optical system.
Although somewhat effective for their intended purpose, the prior art devices are complicated and expensive. What is needed is a mechanically simple, inexpensive system for correcting parallax in a camera having an independent viewfinder. This object, as well as others, is satisfied by the present invention.
SUMMARY OF THE INVENTION
A parallax compensation system and method is provided for a camera including a non-through the lens viewfinder. The taking lens of a camera is mounted eccentrically in a cylindrical lens barrel. The lens barrel is rotated to shift the taking lens towards the viewfinder for close focus shots. Additionally, in one particular embodiment, the viewfinder axis is tilted towards the rotated taking lens axis to help eliminate parallax in close focus pictures.
These and other objects and advantages of the present invention will become more readily apparent in the description which follows.
REFERENCES:
patent: 2552244 (1951-05-01), White
patent: 4924247 (1990-05-01), Suzuki et al.
patent: 5173726 (1992-12-01), Burnham et al.
patent: 5461442 (1995-10-01), Ohshita
patent: 5594518 (1997-01-01), Ohshita
patent: 5778261 (1998-07-01), Tanaka et al.
patent: 6243539 (2001-06-01), Chen
Adams Russell
Concord Camera Corp.
Dalakis Michael
Lampert Scott L.
Sisselman Kerry
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