I was definitely blessed that this gray screech picked a perch after leaving the hole where I could align myself with some nice color in the background, since there was very little color remaining. Surprisingly it sat on this perch for 6 minutes, which for a Screech owl that just left his hole is oh, so long.
I find these out of the hole shots the toughest to get anywhere in focus. First of all, it's pretty dark. Too dark for autofocus to work accurately if at all. And in such low light, it's difficult to see even when the subject is in focus.
But the biggest problem is, most of the time when an owl flies from its hole in the evening, it's all hyped up and constantly swiveling its head back and forth looking for its next meal. The big problem is, as was the night I shot this, he had his back turned towards me and 99% of the time, looked away from me.
What sometimes I do is just focus on the back of his head and quickly try to grab some shots when I can see an eye or two. But that has its drawbacks. With the fast (f2.8/f4) lenses use, the depth of field is extremely shallow. His eye can be in focus and his beak slightly soft for instance. So, I have to hope his eye(s) will be in the exact distance as the back of his head when he turns toward me. After I grab some insurance shots this way, I usually wait till he turns towards me, which could literally be only one second here and there, and focus on an eye. Then, the next time he turns towards me to some degree, is when I click the shutter.
It gets very stressful because you never know how long he will stay on that perch, and oftentimes it's too brief to even find him in my viewfinder. And since I'm always doubting my focus, I keep going through this process again and again if time allows. It's always hit or miss, and my success rate is poor, but I'm exhilarated when after he flies off, can check a few frames and find one I think the focus is good enough.
Out of the six minutes he was on this perch, out of about 100 shots, I didn't get one that thought was my definition of sharp, but DXO and Topaz certainly help.
Even when photographing them in the hole, I refocus every single time the owl moves in the hope of getting the sharpest photo possible. And with such slow shutter speeds, even if the bird actually is in focus, any fine movement of the bird, or the tree limb due to wind, you're pretty much guaranteed a pretty low keeper rate.
Lastly, with such long, heavy lenses, every time you touch the lens to focus, it takes a while for the setup to stop vibrating which causes a loss of sharpness. Try this. Zoom into your subject as much as you can. have a button program to enlarge the image to 50% or 1:1 actual size to make it easier to focus. So, zoom in as much as you can, and while looking at your camera back, just tap your camera and see how much your image jiggles around before it settles down.
It might take a second or two. So do the math. If the owl turns towards you for only 3 seconds, and it takes you 2 seconds to focus, and one or 2 seconds for the camera to stop vibrating.
This photo was taken hour after sunset at.4 sec 8000. The color of the background is real.