thats the whole point. the third render was cropped, the first was not.
so people who want a nice huge render but their computer cant handle it, or they want to slowly build it and have stopping points, they can crop the image into areas while using the detail from camera instead of crop such that the shadows match up.
the left side is one crop, the right side is the other crop, look at the bottom line that goes red to green to see when the crop happens. if you notice in the second one, following that line is where shadows distort and act funny and doesn't add up together as nice + shadows on the right look funny and non realistic. In the third one i did the exact same crop, but the shadows are correct and match up etc.
