Dell Home has Canon PowerShot SD550 digital camera with 3x optical zoom for $399 - 20% coupon XNSHSW7S7DM71G - $35 off 300 coupon QFTPZQCNBRH9TD = $284.

1/1.8" sensor is bigger than 1/2.5" sensor. The SD550 has a less dense sensor, meaning that the pixels are larger, get it?

Imagine a population of people. When you say the population is less dense that means you have more space per person. Now, SD550 has 7.1 mp to fit into a 1/1.8" sensor while the newer models have 6 mp to fit into a 1/2.5" sensor. By my calculation there are more space per pixel (the pixels are bigger) on the SD550.

The biggest difference between the two are the image sensors.

SD550 = 1.8" sensor packed with 7.1 million photo sensors.
SD600 = 2.5" sensor packed with 6.2 million photo sensors.

SD550 has 1/1.8" sensor while SD600 has 1/2.5" you making it look like SD600 has a bigger CCD when it fact, it's smaller. not even the top SLRs have a 2.5" sensor.

SD550 = 1/1.8" sensor packed with 7.1 million photo sensors.
SD600 = 1/2.5" sensor packed with 6.2 million photo sensors.

yes MP doesn't mean anything, BUT, SD550 still beats SD600 in image quality (not sure about SD700 yet).

The only thing good about SD600 is its smaller size, but SD550 isn't that much bigger, so the prices are the same I'd recommend SD550.

compared to the sd500/550 i think the only differences are the weight (sd600 1 oz less), the 600 adds an 800 ISO setting and the 600 has a 2.5" screen (same as the 550) vs. the 2" for the 500. The big difference is megapixels though (sd500/550 has 7, sd600 has 6).

I give the sd500/550 a slight edge

I think you guys are missing the big picture on the difference between the the SD5xx and the SD600. The biggest difference is the lens. The lens was the biggest difference going from the SD400 to the SD500. The lens for the SD500 is a larger lens more comparable to the lens on the standard S series cameras. The SD600 has a comparable body to the SD400 series and I'd imagine a similar lens which in many reviews was noted as having more trouble with soft corners than the larger SD500. While people make a big fuss about pixels, people often forget that lens quality makes a huge difference in pic quality moreso than megapixels. My 3mp Pany with the 12x Leica zoom takes pics on par if not better than my SD500. So when pocketability isn't an issue I'm bringing the Pany.

So the combination of less megapixels and the smaller lens are the reasons the SD5xx will have better PQ over the SD600. Will it matter for many consumers considering the difference in price? maybe not. Price and a little more pocketability might be more of a consideration than the difference in pic quality.

SD600 is the upgrade to the SD450 (square body)
SD700 is the upgrade to the SD550 (tapered body)

do the SD550 and SD700 are higher end in their respective generations. It's strange that Canon is not phasing out their older models while still introducing new ones...

why is everyone comparing the SD600 to the SD550? because 600 is bigger than 550?

i think it goes like this
SD400 --> SD450 --> SD600/SD630
SD500 --> SD550 --> SD700IS

is this a good deal

Canon SD500 vs. Canon SD550, 2005-11-06

The Canon SD500 and Canon SD550 are both very capable digital cameras. While they are similar in many respects, the list price is not one. With the SD500's list price at $499.99 and the SD550's at $549.99, you might wonder what you are getting on the SD550 for that extra fifty dollars. Hopefully this comparison will help you find out.
The Similarities begin with the image processor. Both cameras utilize the DIGIC II image processor. According to the manufacturer this allows for "superb image quality through improved colour gradation and white balance accuracy". Since both cameras have this processor it affords an advantage to neither when deciding which camera to buy.
The similarities continue with the amount of mega pixels. The SD500 and SD550 each have 7.1 mega pixels. This means that pictures taken with these cameras will still be detailed when enlarged.
There are only really two differences between the SD500 and the SD550. The first difference is the size of the LCD screen. The SD500 has a two inch display. It may not be the biggest on the market, but it works well. On the other hand the SD550 has a two and a half inch display. The extra half inch on the SD550 does make it a little easier to make out details than on the SD500.
The second difference is the number of shooting modes. The SD500 has 13 shooting modes, which in my opinion is more than enough if someone was just looking to buy a camera to take on vacations or to family outings. The SD550 on the other hand has 16 shooting modes. Those extra shooting modes may come in handy for the more serious photographer.
I think it is safe to say that both the SD500 and the SD550 are good cameras. If you have the extra fifty dollars to spend I would suggest the SD550 with its half inch more screen and 3 extra shooting modes.