I have written and talked about this before. But I thought that it was time to revisit the issue on full frame or cropped camera sensors. As many will know I have a number of cropped sensor cameras and I love them. But after hearing so much about full frame, and not wanting to be narrow minded, I have been looking into a full frame sensor camera. Yesterday I had the chance to take some side by side tests using a Canon 70D and a Canon 5D Mark III. The test was done using the following settings. 400 ISO, 1/500s @ F14 using a Canon 24-70 F4 L lens (same lens on both cameras). The images were shot in RAW then converted using the same settings.
My first thought was that I like the wider shot that you get from the 5D using the same size lens. This is not up for debate and it is one of the things that would make me switch. But I have wider lenses and if I needed to I could easily put on a wider lens. This would get a similar perspective with my 70D. In order to do a little more testing I took both images and enlarged features to be the same size and compared sharpness and grain. The result was no real difference between the two cameras. In one part of the image the 5D was sharper, but only in the slightest. In another part of the image the 70D was sharper, but again only in the slightest.
So my conclusion is that these cameras do have different features that may benefit different photographers. The image quality is not one of the things that I would use to determine which one to buy.