Archived posting to the Leica Users Group, 2000/03/10
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]> I was talking to someone this lunchtime about why it should be that digital > camera design should have pursued cramming more pixels onto small chips, > rather than enlarging the chips up the size of 35mm frames, thereby > facilitating the union of the two technologies. > The reply was that the manufacture of large chips is a most complex and > difficult one, whether this will ever be overcome, I've no idea. [Austin] That is correct. One issue is the size issue, both going smaller and larger. It is uneconomical to make the cells larger, therefore making a larger chip to cover the larger area the lense projects to. The smaller they can be made, the more that can be made at once, and therefore, the more economical each one is. Secondly, it is expensive, and though getting better, there is a 'yield' problem when you put more cells in a larger area. If cells are bad, and the odds of them being bad increase with the more you have. Given the same process, the entire chip can be of no use. Given a 1/4" CCD is, say 640 pixels square, and a 35mm film plane is 1" x 1.5", that would be a sensor of 24 times the size...that's a lot of pixels. 2560 x 3840 pixels. Do-able, but QUITE expensive given current day technology. That would be an array of 9.8M pixels, and say 8 bits per color, so a single picture would be around 30M....and storage technology isn't quite there to make this really work if you want more than 10 or 20 pictures per 'roll' (read as 340M mini hard disk). Also, there is the time it takes to scan an array of that size. Say it runs at 10ns per pixel (all three colors at once), so it would take 300 milliseconds to scan the array... That may or may not be a problem... It's something that we will probably see in 3-5 years or so. There is quite a bit of new technology that has to be 'accomplished' in order to make this economically feasible. - -------------