Back Button Focus – Why To Use It – How To Set It Up

A reader sent me an email asking about the back button focus on cameras.  Specifically, the question below.

I don’t get the difference between doing that and simply shifting the focal point. Is there a difference?

Before talking more about the back button focus feature of cameras, I want to quickly answer the reader’s question.

Yes, there is a big difference between back button focus  and shifting the focal point.  First I will talk about shifting the focal point.  When someone refers to focal point shifting he/she is typically referring to using a large aperture and then opening up to a small aperture.   The effect of this is a change in depth of field and the amount of the foreground and background are in focus versus blurred.  You can learn more about that at Photography Life.

Back Button Focus

back button focus

Now on to one of my favorite camera features, back button focus.  This is where you set a button on the back of your camera (typically near your thumb) to obtain focus.  On many cameras, setting the button that way will disable the shutter’s half-press focus feature.

An advantage to using the back button for focus is that it will prevent your lens from re-focusing when unwanted.  It will enable your camera’s lens to stay manually focused when the button is not pressed.

That way when photographing a landscape, a long exposure, sports or any subject matter really, you have better control over auto-focus.

It also helps for improved focus tracking when capturing motion.  Combine the back button focus with a continuous style focusing mode and you will see much better results than if half-pressing the shutter.

To learn more about improving your focus I recommend reading my friend James Brandon’s eBook, Tack Sharp.

tack sharpOf course, there are many great videos available to help further explain this function and to show how to set it up for your camera.  Here are a few great ones.

I can’t leave out some awesome articles about the feature as well.

I hope by now you understand the difference between the two and why to use the back button for focusing.

If you have questions please comment and I will answer anything I can.

Thanks for reading and happy shooting,


This Post Has 2 Comments

  1. Although this can be commonly used to stabilize the camera when in hand, this doesn’t work if you use a remote on the camera if it’s on a pole or tripod.

    1. The function still works, however not all cable releases will be able to focus when the camera’s back button is set for focus. Because cable releases typically duplicate the shutter button functions.

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