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Old Sep 17, 2004, 10:27 AM   #1
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Consider the Canon Powershot S60 (5MP)vs. the Powershot S70 (7MP) for example. Does the extra resolution improve the image quality? or increase the chance of noise?

For a small convenient camera with a small lens, where does the pixel race become overkill?
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Old Sep 17, 2004, 11:06 AM   #2
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I don't know about the S60 versus the S70.

However, I do know of one user that has both the G5 (5MP 1/1.8" CCD) and G6 (7MP 1/1.8" CCD) that has an album containing photos from both cameras taken in the same conditions.

Isee very little difference between them from a sharpness perspective (based on tests of both in the same conditions, taking photos of the same subjects).

One thing is for sure -- the G6 has significantly lower Chromatic Aberrations/Purple Fringing. Canon reportedly used new lens coatings to reduce it (but what kind of coatings is a mystery).

The G6 also has less visible noise (but whether this is a property of the CCD, or is due to noise reduction is also a mystery).

I couldn't help but notice when looking at the right side of the building photos, that the G5 appears to have better detail in the shadow areas (near the right bottom, just before the overhang area).

Now, I don't know if it's camera angle, loss of detail from noise reduction in the G6, less dynamic range from the smaller photosites in the new sensor, or what....

He has sent the camera back into Canon (he says that he's noticed the left side is soft) -- so it may have been a defective camera.

Here is the album with photos from both:

http://www.pbase.com/dj__ioni/inbox

Here are two crops from the same area of the building from both cameras. I resampled both to 300% using Lanczos. The vertical line in between some areas of brick actually disappears in one place with the G6, but is still visible with the G5:

G5 Crop (300% enlargement):




G6 Crop from same area (300% enlargement):




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Old Sep 17, 2004, 11:55 AM   #3
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Thank you Jim.The examples you've pointed out arevery interesting. My guess is that improvements to the technology (not just resolution level)are contributing to the reduced purple fringing and noise. I suspect we'll see some huge improvement in the next couple of camera generations.

For the full size cameras with bigger lens and advanced light management... the higher the resolution the better.It's hard to find the breakpoint iin the pocket cameras.



Thanks again. That really helps.
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Old Sep 17, 2004, 1:06 PM   #4
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Well, from what I'm seeing... it appears we've gone past the point of diminishing returns from a resolution perspective.

In other words, I don't see any increased detail with a 7.2MP sensor (in fact, it looks like less detail in shadow areas compared to a 5MP sensor to my eyes).

I suspect that this is becausenoise reduction techniques either in the sensor or in the camera softening the detail.

So, I'm not so sure we're really making progress (other than 7.2 Megapixels sounds better from a marketing perspective).

Now, if I had to choose between a G5 and a G6; I'd probably go with the G6 (just due to the reduction in purple fringing and increased speedof the camera).

But, personally, I'd rather have the 4MP 1/1.8" CCD as used in the older G3, with the new lens coatings in the G6, with less aggresive noise reduction in the camera.


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Old Sep 17, 2004, 3:56 PM   #5
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In general, more pixels, given the same sensor size, results in more noise. There are programs that, to a degree, deal with noise. Having said this, megapixels alone is not a good way to measure a camera's output. Factors including processors and lenses are at least as important as the number of megapixels.

Larger sensors, like those found in digital SLR cameras, are really better than small ones. The quality of pictures from a six megapixel DSLR is far superior to that of a six or eight megapixel point and shoot, especially at higher ISO values.

The recently introduced Canon EOS 20D packs eight megapixels onto the same size sensor as the older EOS 10D which has 6.3 megapixels yet produces better pictures with less noise (from what I've read). This is due to improved processing inside the newer camera. Neither of these has the pixels density of the hight pixel count point and shoot cameras.

I have printed some very nice 13 X 19 inch pictures from my 2.6 MP Canon Pro90. It takes some manipulation of the picture files to get decent results, but has made me a believer in the fact that megapixels is only one factor in choosing a camera.
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Old Sep 18, 2004, 7:11 PM   #6
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Along with a lot of others, I sure like my Pro90. I recently put a Raynox 2.2x telephoto on it for a 22x zoom and can hand hold it. I have also put this lens on my FZ10 for a 26.4 zoom. Myself I do not think I could get away with this with the higher MP cameras? ....but then....I don't really know?
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Old Sep 19, 2004, 11:30 AM   #7
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Chip in a couple of points:

First, one source of noise in a digicam is in the signal amplification coming out of the CCD chip. That is why noise is proportionally worse at high speeds -- the signal has been boosted more, but so has noise, so the ratio of the one to the other decreases. Now, as chips become more sensitive, there is less need for amplification, and so less noise. Same size of chip, same (or even more) megapixels, less noise. So, many new 4mp sensors, for example, are much cleaner than those produced a couple of years ago. Think of the analogy with film: fast print film, circa 30 years ago, was dreadful. Now, its often hard to tell from ASA100. Same size negative, though...

Second, the noise that shows up on screen is different from the noise that shows up on a print. If you print your pictures, especially if you don't print big ones, noise is much more difficult to spot.

Yours,

DB
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