There has been some questions recently on our workshops about the best way to focus. Specifically, with all the amazing tracking and autofocus patterns why not just set your shutter button to focus and take the picture. Less is more…or is it? Before modern mirrorless cameras came out there was an obvious advantage to using back button. Ever heard the saying “focus, recompose and shoot”? The idea was you would use the back button AF to focus on a your subject, then recompose the shot moving the subject off the focus point, hit the shutter and take the picture. You didn’t want the shutter to engage focus since the subject was not in the center, or the focus just wouldn’t find the subject easily. The shutter just took the photo, no autofocus was engaged.
But then advanced autofocus and subject tracking was introduced with modern mirrorless cameras, and it is truly amazing. Your entire viewfinder is now active using subject tracking, not just a few points in the center. Just get the subject in your viewfinder, hit the shutter {which also engaged focus}, and get tack sharp photos. You never needed to recompose and shoot since the autofocus always found the subject. And it is sure easier just to hit one button instead to trying to hit two buttons.
But does modern autofocus always find the subject? The short answer is no, all brands of cameras still miss certain images. We see it every workshop…Sony A1s, Canon R3s, Z9s, OM-1s…they all have situations where they struggle to get focus. The good news is these tough focus challenges are less and less an issue as autofocus gets better and better.
So which way is the best way to autofocus? If you are a “shutter button focuser”, ask yourself are you missing shots because autofocus is moving off the subject when you hit the shutter button? If the answer is you never have this problem, then stick with what works for you, which may be shutter button autofocus.
My default is back button focus, in part because of muscle memory and shooting this way for years. But I still find daily situations where I don’t want my camera autofocusing when I take the image. Take a look at the bear image at top. With this specific shot the Z9 had no problem finding an eye and focusing. But as the bear got lower and more obscured by grass, the autofocus starting racking back and forth as the camera tried to find an eye. If I was set to shutter button focus, every picture the camera would be focusing back and forth trying to find an eye. But using back button I just stopped engaging focus by not hitting the back button. I already had focus when the grass wasn’t blocking the eye, and the bear was in the same plane of focus as it lowered its head. So I kept taking tack sharp photos hitting the shutter and not engaging autofocus. Some cameras were switching back and forth from the ear to the eye with every shutter click, better to use back button here as well. A lot depends on what you photograph. Less busy backgrounds and cleaner subjects shouldn’t have this problem. You could set your autofocus to single servo, but then you wouldn’t be tracking moving subjects. I alway shoot in AF-C (continuous servo) mode, but my camera only hunts subjects when I hit the AF back button.
There is a good point to be made that learning back button focus is tricky, and you will miss images getting the coordination down. And always remember this….whatever technique or style is working for you is what is most important. Read/watch all that technique content on the internet, take away what you will from it, but in the end do what works for you! There are no right or wrongs here. In fact I sometimes turn on my shutter button AF…
In the winter here in Alaska I shoot in sub zero temperatures all the time. I love to use Heat Company mittens since mittens keep my hands much warmer than gloves. But feeling the small AF back button through thick mittens is very difficult. So I have been turning my shutter button AF back on since I can easily find the shutter button using my mittens. As long as the autofocus can find the subject, shutter button autofocus works great in super cold weather.
If there is one thing that modern mirrorless cameras have shown us it is there is rarely one mode that does it all perfectly. We can program different buttons and shooting modes any way we like to get the best performance from our camera. Customize your camera to work the best for you!