This is my first comparison of the three 300mm f2.8's, and the 400mm f4, alone and with the 014F 1.4x teleconverter (a lens p0rn pic
here ). The DFA 150-450mm provides a point of further comparison.
The 107B and 360B are in very good condition, the 400mm 65B is a bit more worn but optically pristine, my 60B is a bit of a beater, it was very worn when I acquired it about 5 yrs ago, and then I dropped it (it slid out of a Lowe slingshot pack when the zip undid) onto the mount end, subsequently I have not been able to use PKA mounts and the aperture ring is stiff and doesn't click.
My usual test subject - a turret on Conwy castle with good bright sunlight. I used my K3-ii, M mode and manual focus with all lenses using 10x live view, manfrotto 055Xprob tripod with Slik 800 (~45mm) ballhead (all the lenses have plates to balance them), remote shutter cable. Actually I found this set up to be a bit prone to vibration, I ended up pressing a finger against the side of the camera a lot to try to supress that, and I had to switch off SR. I didn't end up with any images obviously showing shake (and I upped the ASA to 200 and 400 rather than dip the shutter speeds below 1/320th) but it's a potential source of inconsistency/error.
Cropped section was also approx the point of focus. 300mm pic 1. 400mm pic 2.
300mm lenses alone. "Filmstrips" by f stop.
300mm's + 014F tc = 420mm, and 400mm 65B.
Observations.
First thing I can say is that these are all very good lenses. Second, the DFA 150-450mm stands tall against some heavyweight vintage competition. However both the 60B and the 65B yield little/nothing to the DFA at optimum F stops: f5.6, f8. The "beater" 60B is the surprise front runner of the 300's. 107B is a tad softer at wider apertures, improving as its stopped down and eventually catching up at around f8. My 360B is a slight disappointment, it's possible I have a slightly "off" copy, it is also possible that this is a lens where you're always chasing critical focus without ever being sure you've actually nailed it, it's that ticklish! The 400mm 65B is impressively consistent, definitely holds an edge over the 300's+tc, although the 60B+tc is very close. Comparing wide open 65B image resolution with the DFA (I am using a hazro 27" IPS screen these days, a big upgrade over my old one), the DFA edges it but its very close. F5.6 vs f5.6, still DFA by a short nose imo. At F8 I can't put one ahead of the other. The DFA also has no purple fringing of reflections off the lightning conductor.
65B also performed well with the 1.4x tc at 560mm.