If you are in love with full-frame cameras, then just buy a film camera. The price is much cheaper than digital, and the photos developed will be much better than those combined with photosensitive chips.
Let’s talk about the difference between 50D and 40D. From Canon’s official point of view, the launch of 50D is a big span! This is Canon's first camera using DIGIC IV. The processing speed is more than 30% higher than that of digic III, and the pixels reach 15 million. The most important thing is its CMOS, which is a brand-new CMOS designed by Canon itself. Of course It has not been market evaluated yet! But what should be noted is that Canon's design team will start to design its own CMOS patents from now on, and may develop its own X3CCD like SIGMA. Since this CMOS is Canon's first product, it should have a greater advantage in quality.
As for the area of ??CMOS, you should not pay too much attention to its size. Imaging is related to it, but the size is not entirely determined by it! You can look at Sony's H9, Fujifilm's S8000, Olin's SP560, and Canon's S5is that were launched last year. They all have the same CCD, Sharp's 1/2.5-inch one, but the image quality of these cameras is the same. ? Are the noise reduction capabilities the same? Therefore, camera design is a very comprehensive technical application issue, and it does not depend on one or two small issues