Addendum - new vs. old Canon 100-400mm
In my previous post on this lens, I used a 1.4x teleconverter on both lenses. I got a request to repeat the test without the teleconverters, so here are the results. These are all shot at ISO 400, f/5.6 at 400mm, 1/1600s, autofocus with the center point, RAW. It is later in the day, and it looks like light clouds and shadows moving in the breeze are slightly changing the lighting between the shots, so caveat emptor. First the whole image with the old lens: Next, the new lens: Here are the locations of the crops I took: First, the center crop. The old lens: The new lens - again, sharper even in the center (although the moving shadows from the windy day make it a little harder to tell): The left edge crop, the old lens: The new lens - significantly sharper: And now, the corner crop, the old lens: And the new lens. It is no contest: The chromatic aberration is not as bad with the old lens without the teleconvert...