pseudoghost wrote: Don't believe the 18MP hype though, it won't make a big difference. You can't really crop images on either camera, as they're going to be too noisy to be useful. But you shouldn't be cropping images from a camera with such large zoom anyways (you should be zooming instead of cropping).
I agree there is a saturation point for the extra pixels. It is to a large degree a marketing scheme to be sure. And I recognize the practical difference between 12 and 18 megapixels is not as dramatic as the figures suggest. But I also think the counter opinion espoused by many that higher megapixels are unequivocally worse is just as much nonsense. Because, like most things.....it depends.
There are a myriad of factors that comprise the entire discussion.....such as lens quality, sensor size, and the processing engine of the camera. The latter two of those three things have improved dramatically since the inception of digital cameras, and today's cameras are capable to a large extent of extracting quality resolution within the framework of "higher" resolution (ironically Sony has made some of the biggest advancements with their sensors). For example, one of the improvements has been to shrink the amount of space "between" the pixels, as well as other improvements to maximize sensitivity. Also you will notice some of even the point and shoots today have faster glass which allows more light to help with the signal to noise ratio and help raise the ceiling of maximum resolution.
So yes, more MP is not always better if those other issues are not resolved. But it can be enough of a difference when cropping.....actually especially
the more you zoom (the anecdotal insight of other issues you stated about the two cameras notwithstanding). I understand there is a big difference between a DSLR and a point and shoot primarily because of the sensor size, but I'm not talking about massive amounts of cropping.....just enough to serve as a useful method of editing (for a variety of reasons). If you don't crop some of your photos, then you either take perfect compositions every time....or you are not aware of things that detract from the scene. Or, you simply don't care.....in which case why worry about any of this stuff?
Finally, noise tolerance as it applies to "useful" is relative to the eye of the beholder.....and there are noise reduction software choices to help mitigate its effect in many situations. I think for all practical purposes, shooting at low ISO in good light (to make noise less relevant) and considering even a 20% difference in "true" resolution between 12mp and 18mp in this case......there is every reason to believe there will be more latitude for cropping (without suffering significant image degradation) with the Sony vs the Canon discussed here. For example, even within the framework of 20X optical, there are still reasons why one can't get close enough to a subject to capture it to their satisfaction. Along those lines, cropping can also do more than just clean up an image.....it can bring the subject closer. That's where the extra pixels can play a role.