Shot in Brian Piccolo park. Nikon D300, 600 mm f/4 VR lens with 2x teleconverter.
f/20, 1/50 sec, ISO 800, with flash (don't know the compensation), manually focused, on Wimberly.
I should have bumped up the ISO to get a better shutter speed, but didn't realize it at the time. Only minimal crop for symmetry of the background, but otherwise full frame, as shot. A question for y'all: a wise bird photographer (whose name rhymes with 'ladle') suggested I shoot (focus) right between the eyes - which I did. Of course, this is what's most in focus, but the eyes, not so much! Any ideas? I'm already at f/20. I don't think it's a function of slow shutter speed.
I think you problem is not DOF but shutter speed. The 2X does not help either.
That is a combination for good light and many images to get a sharp one, with good light. With low light, you chances diminish considerably.
Is that noise in the iris?
The image looks sharp enough for me, very good considering that it was shot at 1200mm and 1/50s.
How close were you from the bird? Maybe the DOF was very shallow and the camera/lens are front-focusing.
Maybe a micro-focus adjustment would help bringing the eyes into focus.
I was quite close. Even with a faster shutter speed, I'm not sure why the eyes would then come into focus, as the area between the eyes and above the bill/beak seem sharp to me.
I selectively noise reduced the iris. I think what you see in the iris is not noise, but the detail that we may not normally seen in these birds when shot "wider", Fabs.