Talk:Four Thirds System

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[edit] Name explanation

Can anyone explain the connection between the name "four-thirds" and the size of the sensor? The article presently contains the text

The name of the system comes from the size of the imaging sensor. The sensor used is a "4/3 inch" type sensor. The length is based on the diameter of particular size of Vidicon tube—the actual light sensitive area being smaller. The actual length of the sensor diagonal is 22.5mm.

So more specifically, my questions are: In what way does the name come from the size? In what way is the length based on the diameter of some Vidicon tube? Note that 4/3 inch = 33.9 mm, which is much bigger (50% bigger) than 22.5 mm. That is, the sensor is nowhere near 4/3 inch in diagonal. Fg2 04:56, August 11, 2005 (UTC)

Indeed it's not the physical dimension of the sensor. There's a good explanation of the confusing fractional definitions camera manufacturers use here: http://www.dpreview.com/learn/?/Glossary/Camera_System/Sensor_Sizes_01.htm. 203.132.65.32 08:45, 23 December 2005 (UTC)

Thank you. I've wondered about that for a long time. Fg2 11:30, 23 December 2005 (UTC)

[edit] Image proportions:

I have asked this question on Olympus press meeting, and after few days, I have received e-mail from their technical division:

question: If the image circle is a part of a standard, does it mean that the sensor does not need to have 4:3 proportion? Can there be a camera constructed, by a manufacturer, meeting the 4:3 standard and have the square (1:1) image sensor put inside the same image circle?
Answer: yes just the circle is defined that the ratio of the sensor can also be different from 4/3, but 4/3 was determind as perfect measure.

—The preceding unsigned comment was added by 217.113.234.202 (talk • contribs) 17 March 2006 (UTC)