A half year ago a source sent us a rumor about a Olympus prototype camera that sues a semi-transparent mirror (What Sony calls Translucent). Good to know that the rumor was correct because today we found the patent that explains how it works! Download the pdf at http://www.freepatentsonline.com/7889268.pdf. The many difference between the Sony solution and the Olympus patent is that you can flip up the mirror when you want to avoid the light loss you have using the semi transparent mirror.
This is the original description copied from the patent:
“The digital camera of the present invention has a still image shooting mode and a moving image shooting mode, and performs different focusing operations between the still image shooting mode and the moving image shooting mode.
For example, the range of focusing tolerance and the driving speed of a focusing optical system can vary between the still image shooting mode and the moving image shooting mode such as to set the range of focusing tolerance wider or the driving speed of the focusing optical system slower in the moving image shooting mode.
An exemplary structure of the present invention can be expressed as follows. A digital camera having a still image shooting mode and a moving image shooting mode comprises: a mirror member arranged in an optical path of a photographing lens to reflect part of a subject light beam passing through the photographing lens and transmit the remaining part of the subject light beam; an imaging part for receiving the subject light beam transmitted through the mirror member to output a subject image signal; a distance measurement part for receiving the subject light beam reflected by the mirror member to detect a defocus amount of the photographing lens; and a focusing part for performing a focusing operation to drive the focusing optical system in the photographing lens to an in-focus position based on the defocus amount detected by the distance measurement part, wherein in the still image shooting mode, the focusing part performs a first focusing operation prior to still image shooting, and in the moving image shooting mode, the focusing part performs a second focusing operation different in mode from the first focusing operation during moving image recording.
According to the present invention, there can be provided an easy-to-use digital camera capable of acquiring both still and moving images.”
And that was the description of the prototype the source has seen:
But there is also a second FourThirds prototype that he is testing. The name is E-P330 (again a FAKE name). It is be very similar to the current E-330. It has a similar technology to the Sony A33/55, but it does not have a translucent mirror, it has some kind of liquid chrystal mirror. The advantage is that you have no light loss when you take the real picture. The mirror can electronically change between 50% translucent and 100%. When you don’t take pictures it uses 50% of the light for the AF-system and 50% for the sensor. When you take the picture it uses the full 100% alight source. The disadvantage is that it is not as fast as the Sony technology and you do not have any AF if the mirror is at 100%. The prototype iuses the same E-620 AF-system. The viewfinder is integrated in the body and has the same specs as the VF2 for MicroFourThirds. The LCD can be tilted and it uses the same GH1[/shoplink] sensor. It takes movies with 720p. You can use an external microphone.
UPDATED: I corrected the typos. Sorry I was in real hurry today and as usual writing article with the iPhone isn’t really helping. + I am sick today :(