A quick test to compare performance between the 100-400 f/4.5-5.6L zoom and the 300 f/4L with 1.4X teleconverter. Note that the 100-400 was inadvertently set at 380 mm for the first set of tests. This shouldn't detract from the results in any significant manner.

Note that the image contains some extreme contrast (notably, the bright aluminum wire), suitable for exploiting any weakness in a lens.

Focus point for all shots was the string of strain-relief insulators. Shot from tripod, remote release, and mirror lockup.

No post processing other than conversion from RAW to JPG.

UPDATE: Added subfolder of some preliminary test shots with the 70-300 DO lens. Processing and lighting are different so they should not be compared to the other test shots on that basis.