John_F Loc: Minneapolis, MN

Does anyone know whether the camera makers specify their sensor sizes in Optical Format. I gather it is a hold over from TV videocon days. It was the tube diameter outside the video sensor which was about 1/2 larger than the sensor diagonal. I am hoping the camera makers give 'real' sensor dimensions.

DaveO Loc: Northeast CT

I certainly hope that you are successful in this endeavor. :thumbup:

rmalarz Loc: Tempe, Arizona

The Nikon D700 specifies the sensor as 36mmX23.9mm (.1 mm short of being a true 35mm film dimension). This creates a need for an image circle of, minimum, 43.21mm for corner to corner coverage.

The same would be required for the various sensor sizes with respectively smaller dimensions to require a smaller image circle.

I'm not sure how much more real that could be.
--Bob

zigipha Loc: north nj

The smaller cameras do use the optical format; 1/2.3, 1/1.7 2/3". Micro 4/3 is called 4/3 because its 4/3 inches in "video tube" inches. Some have 1" sensors, again in video tube inches. Bigger than that they switch to actual sensor size. This is how you get 4/3 of an inch being less than half the size of 35mm!

http://www.techhive.com/article/2052159/demystifying-digital-camera-sensors-once-and-for-all.html

has an example

John_F Loc: Minneapolis, MN

I addressed this question to Canon and learned that their designation of 1/2.3" is the diagonal. One problem is that a sensor diagonal is expressed in milimeters then converted to inches and the reciprocal taken with the denominator rounded-off to one decimal digit. When you calculate backwards from, say 1/x.y, you must consider the probable error of + - 0.05. Fortunately, some camera makers give you the actual sensor dimension, width by height, in mm.

Reinaldokool Loc: San Rafael, CA

Most of the sensors are sized in real sizes, but the 1 inch sensors are sized to the vidicon tube, hence are only about 1/2 inch. It has turned into an industry-wide lie.

Brian in Whitby Loc: Whitby, Ontario, Canada

Height x width is really the only method that gives the user solid information. Ever since the 3 x 4 aspect ratio ceased to be the standard fof TV, manufacturers have been misinforming and misleading customers. A 50 inch screen, if it is a diagonal meaurement has a different screen size if it is a wide format, making it difficult to compare to an older 3 x 4 format. It doesn't even make sense now because the diagonal measurement was originally the diameter of the circualr screen. Most of the same ambiguity carries over to sensor size. Actual dimensions and pixel dimensions should both be included in the specification.

While I am on the topic of misleading the consumer, I will mension the zoom factor. A 60x zoom will not give twice the magnification as 30x zoom since the zoom power is the ratio of thd longest to the shortest focal length of the zoom. A small change to the shortest focal length can make a large difference to the zoom ratio. The only wat a consumer can be properly informed is to be given the focal lengths anf the sensor sizes. The zoom ratio is, I believe an attempt to manipulate the consumer into believing he is getting a larger improvement than he really is.
Sorry if I have hijacked this thread.