ELNikkor

You need one point focus, the smallest point you can get, and put that point on the bird.

bleirer

Letting go will freeze the focus at that setting. So if you are happy with how you are focused and neither you nor the subject are moving then letting go locks that in. You should be in servo, otherwise pressing the back button stops adjusting focus after the first acquired focus, just like a half shutter press in 'regular' one shot mode. Saw this video, might be a worthwhile refresher

https://youtu.be/2AXUzslHnRc

CHG_CANON Loc: the Windy City

Although technical, yes you can release with the assumptions that (a) the subject is in perfect focus and (b) the subject doesn't move and (c) you don't move either, but the 'proper' BBF usage is to hold the button down continuously in AI Servo for the entire duration of shooting. When next out, compare this best practice usage method and the results to the alternative usage / results when not holding the BBF button. The difference should be clear.

franbires

Wow. I can't thank you enough. I missed quite a few shots because of this error.

CHG_CANON Loc: the Windy City

No worries. Hopefully, the sumac and bluebirds remain frequent for the next outing. The zone is great for in-flight. But, when you can use the single AF or expanded single AF, you'll get the best results with the camera and lens focusing very precisely on that one AF.

I tend to 'pump' the BBF. Using this shot as an example, I'd get the AF point on the bird, press and hold the BFF and let 3- to 5 images rip. Then, lift my thumb for just an instant, press again while releasing my next burst. The camera may be locked for every frame, but sometimes it seems asking the lens to restart with the 'pump' gets things slightly better.

franbires

I tend to have difficulties putting that AF point/square right from the get go and then I struggle to get a sharp image. This is especially true with small subjects at long distances. Be assured, I'll be at it tomorrow.

SkyKing Loc: Thompson Ridge, NY

...Fran...you are going to laugh...but I kind of like these shots...they look like an Asian silk painting...?

UTMike Loc: South Jordan, UT

Even with post-processing efforts (attached), Your best bet is to listen to Paul (we do).

(Download)

CHG_CANON Loc: the Windy City

For this example, the zone should have done great too with the an 'obvious' subject in the center of the 9-point group. The Canon manuals call out the single point as being more precise, with the caveat, you can get an AF point to cover the intended subject. Continuously engaging the AI Servo AF should prove the difference regardless of the single vs group of AF points.

Craigdca Loc: California

Thanks, Coach. I can’t wait to try this and the pump technique on my T2i.

Fran, I’ve missed a few, too - thanks for posting and I hope you get that awesome photo soon.

Manglesphoto Loc: 70 miles south of St.Louis

I'M sorry I started to try and help then realized I didn't know enough to help you.
Since I use full manual for 99% of my photography, Not saying my method is best, but it is for me, and BBF is really confusing to me. But I'M an Old Dog !!!

bleirer

Something that strikes me about your sample image is that nothing is in focus. Usually with a focus issue the wrong thing is in focus, but nothing in focus is unusual, which got me thinking. On my 100-400 I keep the focus limiter switch on the 1.8M to infinity setting but I also turn off hunting and turn off continuous focus in the camera settings, to save battery. What I find is that I sometimes have to manually get the focus close to in focus. Your lens has fulltime manual focusing, so you can just turn the focus ring without switching the manual switch. My habit is to get the focus in the ballpark but just short of the target manually, and this gives the autofocus a fighting chance at acquiring the target. You might also check what your hunting and continuous focus settings are. I have a different Canon but on mine i find the continuous enable/disable in the 'camera' tab of the menu number 7, you might set to 'enable.' I find the autofocus lens drive where you tell whether to continue hunting or stop focus search in the 'wrench' menu number 4 under C.Fnii. you might tell it to keep hunting. Your camera is different but likely has similar settings since Canon is pretty consistent.

gessman Loc: Colorado

I really hate to ask but I feel a need to, did you set up your bbf or have it done by someone like a camera store clerk or an experienced friend? Are you even sure bbf has been set up or are you just assuming it has and pressing a button on the back thinking it should work without even knowing if it has been set up or not? I did not see any indication in the exif that bbf was on and used but I am using unfamiliar equipment and exif reader.

PattyW60 Loc: Northwest Illinois

Fran, I have the same camera/lens combo, not that it really matters. Oh, and I also love BBF, especially for birding. :) It has been my preference to use center point focus when shooting birds. Generally, there will be branches or something else nearby, and I don't want to have the camera lock on to something other than the bird. I do use a zone when trying to capture birds in flight, though. Just sharing what works for me. Good luck!

AzPicLady Loc: Behind the camera!

I abandoned BBF because it was just one more thing I had to do, and catching quick shots (like birds) didn't allow it. I am aware that proponents of BBF argue that point, but that's how it was for me. That said, I understand the problem in getting things in focus, as I also struggle with that. When I snap the picture, the focus indicator will say the little red box is directly on the subject. However, after the snap the indication shows not. Either I moved or the subject moved, and sometimes both. I resist using a tripod because of the extra weight element, but I know that probably I can no longer hand hold with sufficient steadiness. Also, when I shoot with the 5D, I normally don't have it set on AI Servo because it's mainly for landscapes. When I use either my 1D or 1DX I get better results because they are set already on AI Servo.

So, are you shooting in Servo? That might help. Are you on a tripod? That might help.