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Megapixels vs Sensor size
My very first digital camera purchased in early 2000 was a Canon S20.
Its sensor size was 1/1.8" and it had 3.3 MP Its sensor Area/MP was 11.6 sq. microns In late 2005, Canon released the S80. Its sensor size was also 1/1.8" but it had 8.0 MP Its sensor Area/MP was 4.8 sq. microns Comparing image quality in Steve Digican Site, the S80's images, as expected, are much better. My question is : What advances in technology allowed Canon to achieve better image quality with no apparent increase in noise level with a much smaller sensel size? Improvement in sensor efficiency? Better lens design? Lower Noise Amplifiers? Better algorithms to process the data? All of the above? Any thoughts on the subject? "Inquiring Minds Want To Know" G Bob Williams |
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Megapixels vs Sensor size
"Bob Williams" wrote: My very first digital camera purchased in early 2000 was a Canon S20. Its sensor size was 1/1.8" and it had 3.3 MP Its sensor Area/MP was 11.6 sq. microns In late 2005, Canon released the S80. Its sensor size was also 1/1.8" but it had 8.0 MP Its sensor Area/MP was 4.8 sq. microns Comparing image quality in Steve Digican Site, the S80's images, as expected, are much better. My question is : What advances in technology allowed Canon to achieve better image quality with no apparent increase in noise level with a much smaller sensel size? Improvement in sensor efficiency? Better sensor design. Better microlenses, lower circuit noise. Better lens design? Irrelevant to nois. Lower Noise Amplifiers? Very much so. It's exactly this sort of area that Sony's been busting their butts. Look through the back issues of Sony's CX-NEWS for articles on sensors to see what they've been up to over the last five years. http://www.sony.net/Products/SC-HP/cx_news/ Better algorithms to process the data? Somewhat, but the tweaks in the sensors are the most important. David J. Littleboy Tokyo, Japan |
#3
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Megapixels vs Sensor size
David J. Littleboy wrote: "Bob Williams" wrote: My very first digital camera purchased in early 2000 was a Canon S20. Its sensor size was 1/1.8" and it had 3.3 MP Its sensor Area/MP was 11.6 sq. microns In late 2005, Canon released the S80. Its sensor size was also 1/1.8" but it had 8.0 MP Its sensor Area/MP was 4.8 sq. microns Comparing image quality in Steve Digican Site, the S80's images, as expected, are much better. My question is : What advances in technology allowed Canon to achieve better image quality with no apparent increase in noise level with a much smaller sensel size? Improvement in sensor efficiency? Better sensor design. Better microlenses, lower circuit noise. Better lens design? Irrelevant to nois. Lower Noise Amplifiers? Very much so. It's exactly this sort of area that Sony's been busting their butts. Look through the back issues of Sony's CX-NEWS for articles on sensors to see what they've been up to over the last five years. http://www.sony.net/Products/SC-HP/cx_news/ Better algorithms to process the data? Somewhat, but the tweaks in the sensors are the most important. David J. Littleboy Tokyo, Japan Even though lens quality doesn't affect noise, it certainly affects the sharpness of the image. A sharp lens would allow the smaller sensel to capture as much or more detail than the larger sensel captured with a poorer lens. Bob |
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Megapixels vs Sensor size
Bob Williams wrote:
Even though lens quality doesn't affect noise, it certainly affects the sharpness of the image. A sharp lens would allow the smaller sensel to capture as much or more detail than the larger sensel captured with a poorer lens. Bob Making sharp lenses for smaller sensors is much simpler and less expensive than for lenses as sensor size increases. The entire compact camera with lens by Zeiss etc, costs a fraction of the price of one fixed focal length lens for 35mm with the same brand on it. Forgetting noise performance, and assuming good lens quality then the largest practical difference between sensor size relates to depth of field, and the ratio of sensor size, pixel size, pixel count, and diffraction limitations on resolution. Some approximate comparisons are that a 1 1/8" sensor at a given focal length equivalent and focus distance offers a similar depth of field when the lens is open fully wide - say f2 or so, as a typical dslr sensor of 6-8mp at the same focal length equivalent set at the smallest aperture (around f11 or so) above which diffraction effects begin to limit resolution. But the 8mp compact camera with 1 1/8" sensor will progressively lose resolution to diffraction at apertures smaller than about f4 - so there is little scope to use depth of field creatively as for a larger format camera, as there are only a couple of "usable" f-stops before resolution is lost to diffraction. Conversely, the dslr will never be able to provide the huge depth of field of the compact camera whilst maintaining the resolution obtainable at apertures wider than the diffraction limit. The interrelationship between sensor size, pixel count, focal length, focal length equivalent, depth of field, and diffraction limitation on resolution is well explained he http://www.cambridgeincolour.com/tut...ensor-size.htm This web site includes several calculators that can be used to make comparisons between formats. Diffraction effects occur regardless of lens quality. There are some serious disadvantages to increased sensor size as well as serious advantages. |
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