otto uberswengen wrote:
BUT the ball game changes the moment the sensor itself is made
say 50% larger as in the case of the DP1 and S2.
And we've been conveniently ignoring the fact that the sensor is only half the story. It doesn't matter if you have the greatest sensor in the world if it's paired with rubbish optics. There's a reason pro-grade lenses cost a fortune.
To illustrate this point, head on over to the sample comparison page at Imaging Resource
. Compare the images shot by the 10 MP Sony A200 vs 14 MP Sony A350. Look at all the sample images, particularly the still life shots at the bottom of the list which are designed to compare resolving power of the cameras. Tell me that you can say for a fact that the 14 MP has more resolving power. If you didn't compare them side by side, you'd have trouble knowing which one was which.
Now compare the INB photos. Notice that at ISO 1600, the A200 produces less noise than the A350. Look at the dark areas of the shot, e.g. under the leaves, the black scale in her hand. See the speckles that exist on the A350 but not on the A200? Notice that yet again, the resolving power of both cameras are the same?
Obviously, the situation will change if you put a better lens on the cameras, say the Sony SAL16105. This lens has much greater resolution and I believe it outresolves the sensors of both cameras. Only with such a good lens will you will
see a difference in the resolving powers of both cameras since the sensor is brought to its limit. You can look at another site (*cough* dee *cough* pee revue), to see the resolving power of these lenses and you'll see that the resolution of the SAL1870 (which is the lens used by both these cameras) comes no where near the resolution of the sensor.
Where does this leave us?
Is the sensor important?
Yes it is.
Does a bigger MP sensor automatically mean better resolving power?
No it does not. Judge the images with your own eyes.
Does a bigger MP sensor produce more noise?
Yes it does at high ISO speeds. Again look at the test images for yourself.
What else influences the IQ of your photos?
The lens! Use a crappy lens, take crappy photos.
As a corollary of the lens issue, upgrading from an old to new camera usually gives you an improvement in quality. Nevertheless, unless you can control all other factors like the guys at Imaging Resource did, it is impossible to conclude that a higher MP count resulted in a better looking image. It is much more likely that the image quality improvement came from a better lens that was present in the newer higher MP camera.