Sorry if this has already been covered. I did a search and had no luck.
I am trying to decide between size and megapixels. I’m looking at Canon’s SD400/5MP & SD500/7.1MP, but it could be any two cams of similar specs.
This may sound silly but…
What I want to know is; with my current Canon S400, is the reason my shots don’t look like professional ones purely the lighting and manual adjustments to the shots. Or would a higher resolution camera, (SD500/7.1MP), produce the results I desire. I would prefer the slightly smaller size of the SD400 as I take my camera everywhere. However I don’t want to find out later I should have gone with a little more bulk and more megapixels.
Price is of no concern. I want the best quality for my memories, keeping in mind that if I don’t have my camera because it was too big, there is NO picture at all.
Is there any way to get professional looking pictures from a subcompact? Or should I get another camera with better lenses for the really good shots? After all I’m not a professional photographer, but I’d like to practice and get the best shots possible.

As you can see at

http://www.airshowfan.com/guide-to-d...as.htm#dontbuy

compacts will almost always have inferior image quality for a certain number of megapixels. This is because their tiny sensors have a very high pixel density, which leads to grainy/noisy pictures. This gets even worse at higher resolutions, so moving from a 5MP very compact Canon to a 7MP very compact Canon should not improve your image quality very much.

Grain/noise is most visible at higher ISOs, so if your camera allows you to lock the ISO at 100 or lower, and has image stabilization or some other way to expose well even at those lower ISOs, then image quality should be better. The compact Panasonics and the Minolta X1 have image stabilization (I think the upcoming Sony T9 does as well), and the Fuji Z1 has some new technologies that make the sensor less noisy than others at higher ISOs. So those would probably be my recommendations for very small cameras that can have pretty good image quality when the lighting is not perfect. (Of course, in bright sunny days, any camera can take nice, sharp, rich shots).

Some cameras, like the Canon A620, Fuji F10, Olympus C7000, etc, can take extremely high-quality pictures, and are not too bulky. If you want good pictures and a size that is not cumbersome, I would suggest you check those out.

You can get very good pictures with a small camera if you work within their limitations. I have no idea what you define as professional results.

The extra pixels will not give better shots. More pixels let you make larger prints or crop more. But if you don’t crop a lot or print over 8 X 10 you will see no difference.

I would go for the SD450 or SD550 as the 400 and 500 had problems with fragile LCDs.

The SD500/550 has a stronger flash. It also has an excellent sensor for noise at that CCD density. But I think you will get photos just as good with the SD400/450 if you stay within the flash range indoors. The flash range on the SD400/450 is good for its size.

As far as a larger camera, I have always agreed with your approach that the camera you have with you is infinitely better than the one sitting at home when you have a photo opportunity. I have a super zoom stabilized camera for nature shots, but get more pictures with my little camera that is always with me. If I could have only one camera it would be my little one.

The Olympus Stylus 800 is just one example of a pocket camera with an 8Mp 1/1.8 sensor. The Panasonic FZ30 is one of the largest cameras on the market and squeezes the same number of pixels into a 1/1.25 sensor. Camera size isn’t an indicator of pixel density.

Resolution on standard test targets is a good indication of lens quality and sensor abilities. Noisy sensors degrade an image. Dpreview does standard resolution tests on all of their reviews. Look through the reviews and find me a camera of any size with a significant resolution advantage over the SD550. It has an excellent lens and takes very good pictures.

The Sony 1/1.8 sensor in the SD550 has noise characteristics as good or maybe even slightly better than the 1/1.8 Sony 5Mp sensor. The SD450 has a smaller 1/1.25 sensor. The SD550 is slightly better for noise than the SD450.

What you do often get in a larger camera is zoom range, better controls, stronger flash and sometimes better aperture. Those factors can contribute to better photos in some conditions. But they don’t necessarily take less noisy or better quality photos.

Yeah, I guess you're right, some of the bigger cameras use the same small sensors, or even smaller ones. Maybe it's just that the smaller cameras I have experience with happen to have been more on the grainy side, or that the bigger cameras I have are easier to keep at lower ISOs (maybe because larger cameras tend to have slightly faster lenses). I'll have to check out the images these Canons make.

Thanks for the replys guys. I need to do more research I guess. I don't like to be in the dark when it comes to my toys, and I seem to be lacking some knowledge when it comes to image sensors and the like.
I was thinking of my post last night. I'd like to simplify my question, which I think you may have already answered.
Does and increase in megapixels increase picture quality, or simply picture size.
In other words, on the highest quality setting, is the DPI the same for any size setting, or does it get more dense. It sounds like you're saying it may be worse, unless your printing huge pictures.
I only wanted to step up because I took a really sentimental panoramic shot with my S400, and wasn't able to blow it up into a poster size print for framing. I thought more megapixels would solve this. As I said, guess I need two or three cameras.

Thanks very much for the help. It is certainly appreciated.

Niterunner, more megapixels alone, while they provide more resolution and ensure less pixel visibilty in prints, do not necessarily provide better image quality. Many factors are at play. An extreme example would be the latest sub-$100all-in-one cameras that now boast 6Mp, they have cheap, fixed focuslenses, cheap sensors, etc.and while actuallyproducing 6Mp photos, theydon't rival, in quality, the output of a good 1Mp camera. Of course this is an extreme example, but illustrates that when looking at two cameras with more or less megapixels, photo quality cannot begaged by this factor alone.

The SD400/450 doesn’t produce better photos than the SD500/550. It might be slightly the other way round, but you aren’t likely to see the difference in normal use. The exception to that would be for large blowups, for which the SD500/550 is superior. The SD500/550 is a larger camera with a larger sensor.

It doesn’t always work out that more MP gives even an equal picture. As airshowfan points out you have to be aware of things like more noise and inferior optics. The SD500/550 just happens to have a very good sensor and optics. So does the Fuji F10 he mentioned.

If you hold the camera long side up for panoramas you get more pixels in the image assuming you zoom a little to get the same panorama.