Right, sensor sizes, output resolutions and print sizes aside
I post clear, indisputable, incontrovertible evidence that a full-frame camera with a decidedly "meh" lens with a pinhole aperture at high ISO absolutely blows away a P&S camera with a state-of-the-art lens at ideal aperture and base ISO...
Your evidence was disputed by me and you did not bother to answer. Until you answer satisfactorily, your "proof" is not a proof and is certainly not indisputable. I am happy for my arguments to be disproved in a logical manner but will not take you seriously if you fail to consider them.
Alan, I was being gracious in ignoring your complaint, as it indicates that you really don't understand even the simplest fact about what a crop sensor camera actually is. Specifically:
It seems to me that all that "experiment" has shown is that if you use a low quality telephoto lens to take a photo of, say, a small bird sitting in the middle of a tree you get a better image of it than taking a photo of the whole landscape with a wide angle lens and blowing up the teeny weeny central section.
That is exactly
crop format cameras do -- except, of course, that they don't have all the rest of the sensor to crop from, just the teeny weeny central section.
The Wikipedia article is not bad:http://en.wikipedia.org/wiki/Image_sensor_format
But have a look at any P&S camera. Look at the focal length of the lens. Not the "35mm equivalent focal length," but the actual focal length, usually printed on the lens and always included in the specs. They're all ludicrously wide, if the were full-frame cameras. Something like a 4mm - 24mm zoom is not unusual; it would work out to a 24-135 "equivalent." So, if you were to take such a P&S camera and zoom all the way in to its most telephoto setting of "135mm equivalent," you would, indeed, be using a wide-angle lens and be blowing up a teeny weeny sensor, exactly
what I did in that experiment.
And, yes, those P&S cameras take better pictures than just cropping away all but the teeny weeny central section of a full-frame camera, but only because they have sensors with insane pixel densities. Build a full-frame camera with the same pixel density and you'll wind up with a 150, 200 megapickle monster...and then, yes, cropping away all but the teeny weeny central section of a wide-angle image shot with that monster full-frame camera would result in the exact same picture as taken with the P&S camera.
Think back to the early days of digital photography, when even small cameras didn't have a single megapickle in their sensors. (Kodak was the first to reach the megapickle mark in '86.) Imagine you had a camera with a 4mm x 6mm sensor and a whopping 0.7 megapickles of resolution. Slap a 24mm lens on it, and you'd get the exact image on the right in my experiment -- pixel for pixel. That's the actual raw dump of the image, no post-processing, nothing. And that's as good as that camera can do.
Now, use the exact same tech to build a full-frame sensor...and you've got the 5DIII. Now, take another step, and imagine a full-frame sensor built using the same tech in today's megapickle P&S cameras.
That's the whole point of this illustration: that sensor size really does matter.
Is it the whole story? Of course not. I've already pointed out that, though an 8x10 view camera will mop the floor with a full-frame camera, you can't exactly go clubbing with it. But it is
the whole story when it comes to image quality: all else being equal, bigger is always better.