Originally Posted by user
in "original scan and photo.jpg" the scanned image is at the left? why its so small?
The object in the original scan is placed in an A4 scanner so it looks small. The object in the original photo is taken with the maximum zoom allowed by the camera (while retaining focus) to get as large the picture in the frame as possible.
The scanner set at 300 dpi will make 300 dpi scans no matter what is the size of the object, be it an A4 document or a 1" stamp. The camera can zoom to get the object in the frame with little or no background, so the dpi equivalent is greater for smaller object (same Mpixels for smaller size). It is a kind of self-adjusting dpi.
One can say that it is unfair to compare a set dpi in a scanner with a self-adjusting dpi equivalent in a camera, which can much exceed the scanner setting. But my comparison is not about fairness but about practicalities. I will not even try to waste my time waiting for the scanner to take a color scan at 600 dpi or higher resolution. It would take ages.
As for my camera, Powershot Pro 1, despite the name, is not a professional SLR. It is an old "prosumer" camera belonging to the same class as Canon G-series cameras (the sensor is much smaller than the one in SLRs). Later today, I will conduct some tests with the same object and my compact cameras.