The first is the Canon 1Ds3
and the second is the Pentax 645D
This implies it isn't the number of pixels that counts, it is the quality of the pixels. Is it possible that removal of the fuzzy filter will so improve the quality of the dslr pixels as to make up the difference - I simply don't know. But what you are seeing here at 1500% magnfication is why you can see the difference in ordinary size prints.
This even has implications for stitching - I can easily equal the pixel count of the Pentax by stitching two or three overlapping Canon 5D2 images, but the inability to resolve low contrast areas will remain.
And I haven't even begun to look at shadow areas in which the differences between the two cameras is far greater. That Pentax, with all its limitations (no live view, shallow depth of field) may just be what I'm looking for.
Below are 100% crops of the same area, Canon first, Pentax second.