About digital camera aperture and depth of

In the photographs of the so-called standard lens focal length is the length in Imaging plane diagonals prevail when lens diagonal near Imaging surface, the imaging of magnification is 1, the film (or CCD) of imaging and the person's naked eye (eye) can see the scenery is essentially the same. So for different Imaging plane diagonals, the corresponding standard lens is not the same. In the photographs of the so-called standard lens focal length is the length in Imaging plane diagonals prevail when lens diagonal near Imaging surface, the imaging of magnification is 1, the film (or CCD) of imaging and the person's naked eye (eye) can see the scenery is essentially the same. So for different Imaging plane diagonals, the corresponding standard lens is not the same. 35 mm camera imaging surface diagonal length is 45 mm, i.e. real standard lens focal length is 45 mm, but in general common standard lens is 50 mm, which means on film and image magnification is not 1, but is slightly larger than 1. Because digital camera imaging materials CCD size is inconsistent, so different size CCD digital cameras, their so-called standard lens focal length is not the same. Therefore, only a correct conversion for different size CCD imaging surface diagonal size, we can conclude with 35 mm cameras more reasonable comparison data. Following my Sony F717 as cases of conversion. According to the information, CCD size 2/3-inch, lens focal length of the actual 9.7-48.5 mm, maximum aperture is F2-F2.4, which can calculate the IRIS aperture 4.85-20.2 mm, so it's imaging surface diagonal length? in short jiaoduan 9.7 mm focal length, Aperture, f2, converted into Aperture F1 IRIS aperture should be 9.7 mm, Aperture blades and imaging surface a distance between, imaging surface diagonal length must be greater than 9.7 mm, but specific dimensions only projections. Information on this lens is equivalent to a 35 mm camera lens 38-190 mm and 35 mm camera imaging surface diagonal length is 45 mm, 190 mm at jiaoduan magnification is 190/45 = 4.2 times, i.e. maximum jiaoduan is standard jiaoduan 4.2 times, thus we can calculate out this camera imaging surface diagonal size is 48.5 mm/4.2 = 11.5 mm, that is to say with this camera in 190 mm jiaoduan imaging only 35 mm camera on the film of the same jiaoduan the imaging of 1/4. From the above calculation and analysis, I conclude that a bold my conclusion (whether correctly or scientific validation to be friends): that is a different length of CCD imaging plane diagonals, and 35 mm camera imaging surface diagonal length 45 mm do rate conversion, multiple values for the depth of field calculation basis. Due to the lens aperture value changes are based on radicals 2 times that is double the rate of change of 1.414, so you can figure out the aperture series should be increased. Still to Sony F717 as an example, it has worked out CCD imaging surface diagonal length is 11.5 mm, 45/11.5 = 3.91 (times), and then converted into Aperture series 3.91/1.414 = 2.7 (grade) of the above is incorrect, please submit to friends! below table lists some common nowadays CCD size digital camera in depth conversion should be increased IRIS series (Note: the depth of the comparison must be the same as in the same jiaoduan, distance and the same was taken from premise is meaningful). Common CCD size and 35 mm cameras interchangeability table: depth of field CCD imaging surface diagonal size (mm) aperture change series 1/3.2-6 plus 5.5 1/2.7-6.9 plus 4.5 1/2.5-7.47 plus 4.3 1/2.4-7.94 plus 1/4-9 plus x 1.8 3.5 2/3-inch type 11.6 plus 2.7 17.3x13 mm 21.64 plus 1.5 23.7x15.6 mm 28.37 plus 1