As soon as I got the 300/4 I had people asking me to do a comparison of it against my ZD 150mm f2.0 w/ EC-20. I wanted to wait a bit so I could see how the MZ 300mm f4.0 IS Pro shot and that time has finally arrived. I had fully intended on doing this when I did the 300mm shootout but an unfortunate drop caused me to have to wait until today when I headed to the Anahuac National Wildlife Refuge to check the status of Raptors arriving for the winter. While there looking for Raptors (saw a few but no shots, still a little early) I came upon a couple of subjects that allowed me to do a variety of test. The results were as I expected and it also confirmed what I had always suspected of the 150/2 w/ EC-20 combo. Before we can get to the images I guess I should go over the shooting situation and parameters………………… ISO - Auto White Balance - Auto SAF w/ Single Small Auto Focus Point which I moved to a location for a decent composition. Drive - Continuous Low w/ silent (set to 6.5fps)for all images except the ones with flash, for those I was in Continuous Low w/ Anti-Shock. IBIS - SIS1 Metering - ESP EV - +1 Stop for the Cormorant photos (including the flash photos) and 0EV for the GBH Mode - Aperture Priority Flash - For the images with flash I was using my Godox V860iiO mounted on the hot shoe in high speed sync mode. Photos all taken in RAW and processed via my custom preset in LightRoom. The Cormorant images have no crop and the GBH are only cropped to 16:9 (still full length of original file). Handheld w/ Elbows braced on knees while sitting on the ground for the GBH images. For the Cormorant the lens was resting on a pool noodle that was slipped over the edge of my window. I want to point out that in almost every image the 150/2 had a slower shutter speed than the 300/4. It was between 1/3 and 2/3 stops slower, mostly in the 2/3 stops slower range. This was also noticeable when looking through the viewfinder and believe it’s due to the TC because I know bare lens it is much brighter than the 300/4. I also believe my 150/2 w/ EC-20 is back focusing slightly and will likely repeat this comparison after I do a micro focus adjustment later this fall. Now for the photos………………………..