Q&A: Back Button Focusing
“I was wondering if you could explain the pros and cons of back button focusing? Thanks :)”
For those who don’t know, there is a button on the back of most DSLR cameras that allows you to focus your image without pressing the shutter button halfway down (which is the more common way to focus). There are some pros and cons to each method…
When you are using the shutter button to both focus and take a photo, you have to push halfway down to focus and then all the way down to take the picture. If there is any sort of delay between the two (for instance a child looks away for a second), you have to continue to hold the shutter button down to maintain the focus. If you separate the two functions (ie focusing with the back button and taking the photo with the shutter button), you can focus and then wait to take the shot.
Some people would argue that using the back button to focus is more accurate, but I think what is more important with focusing is that you pick your own focus points (instead of letting the camera choose), and refocusing the camera between each photo. << This is key. That way, if your first photo is out of focus, you have a chance of getting the next image in focus.
A lot of people use back button because it allows them to take a number of images without refocusing their camera, but in my opinion, and the way I shoot, I don’t think that’s the best idea. What if all of your shots are out of focus then?? :)
To summarize these ramblings, I DO use the back button to focus 80% of the time. But I make sure to refocus between each shot so it’s quite possible that I’m doing twice the work by using two separate fingers to do something that could be done with just one.
Also, in case you’re curious – generally the only time I use the shutter button to focus is during the dancing portion of receptions (not formal dances, just crazy everyone’s-having-a-good-time kind of thing). I engage focus on my shutter button, and I actually allow my camera to choose focus points for this because I’m generally holding my camera above my head or something and am not looking through my viewfinder. Obviously, the camera isn’t perfect and doesn’t always grab focus on the right thing, but it’s better than using just the center focus point and trying to aim!
Hope this helps?! :)