Canon EF 400mm f/4 IS ii DO vs. EF 300mm f/2.8 IS ii L for Bird Photography: 4 Months of Experiments

In this video, I will release the results of 10 key experiments between the Canon EF 400DO IS ii v Canon EF 300L IS ii, using the Canon EOS R5 and EOS R7. These results will help you decide which one of these professional-quality, low-light, light-weight lenses is the best for bird photography. Experiment topics included testing for sharpness, bokeh, and focus speed; how the 400 DO handles teleconverters; and the effects of stopping down. Experimental subjects include fake-birds, real birds and two types of test charts. The results were a little surprising!

TABLE OF CONTENTS:
3:06 - Experimental Setup Explained
5:52 - Lens Setup Explained
6:33 - Photoshop & Lightroom Setup Explained
10:13 - Experiments Start
10:15 - Exp#1-before Sunup) 300+1.4TC (f4) v 400 (f4) v 100-400 f/8 (cheap lens)
17:11 - Exp#2)-sun just up) 300+1.4TC (f4) v 400 (f4)
21:15 - Sub Exp#2b) Stopped Down 400DO to 5.6 v 300+1.4tc (f4)
23:43 - Exp#3)- R7 in first AM shade. 300+1.4tc v 400 v 100-400 f/8
28:16 - Exp#4 sunup)-R7 v R5 + 1.4tc - (400DO in both)
33:36 - Exp#5 8:45am: R7 v R5+ 1.4tc (400 DO in both) *then R7 stopped down f/5.6 (wow)
39:10 (Eagles 9am): 400DO+2.0tc v 300L+2.0tc - eagles 75 yards
43:45 (humming birds am closeup): 400DO f/4 v 300L f/2.8
47:59 (super-crop shade - eagles): 400DO+1.4tc (f/5.6) v 300L+2.0tc (f/5.6)
51:15 (test charts): 400DO (f4) v 300L+1.4tc (f4)
54:35 (Snellen eye chart): 400DO (f4) v 300L+1.4tc (f4)
56:23 (Snellen eye chart) Teleconverter Shootout: 400DO only (2.0 v 1.4 v none)
1:01:13 Focus speed and a problem 400DO v 300L
1:04:13 more R7 disappointment confirmed (R5 v R7 w/ 400DO real white-tailed kite).
59:02 - Conclusions