A few days back on an episode of Ask SLR Lounge, Pye went on FB Live and answered a few major questions about: Servo Mode, the proper way to Focus-Recompose, and Back Button Focusing.
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Chris Townsend, an SLR Lounge Premium Member, posed the following question during the episode:
I usually use single spot metering when focusing my camera. Should I use group or single focus when interested in using Servo Mode?
Pye opens up by firstly stating how different everybody’s results will be with their Servo Mode. This is because the performance, more so, results of this method, come down to the camera. Recall:
Servo Mode is when your camera auto-focuses for you as your subject moves. The autofocus functionality for camera bodies that are known for their strong focusing systems (such as the 1D MK II) can easily use all the outside focus points, just as strong as the center. Therefore, shooting in group focus doesn’t matter, because whatever AF point (even the ones on the edges) focuses just as accurately as the center. The 5D MK III, however, as good as it is, still has a center point which is its strongest.
[REWIND: 15 Tips For When You’re Having trouble focusing your camera]
You can test your camera to see how well the focus point system is:
It’s important to remember that walking side to side doesn’t test your camera’s Servo Mode because it’s a change of left to right. To examine how well your camera does, set up a test shot whilst in Servo Mode, where the model walks towards or away from you.
For best results, we recommend your camera being in shutter burst mode.
If you have a strong AF system, then your photos should come out sharp, regardless of single or group auto focus. For the cameras that struggle with their outside focus points, you’ll begin to notice when comparing your center AF point shots to your outside AF point shots, the center delivers in-focus images when tracking a subject that’s moving.
It states in the video that if you find that your shutter is slowing down, it’s probably not the buffer of the camera but rather, your camera body having a hard time locking focus.
With all things considered, Pye prefers using one focus point in his workflow, and if possible, it being the center.
There are situations where using the outside AF point is better than the center. For example, when we Focus-Recompose in studio, we know that if there’s too much movement in-between the position where the focus is locked and the final composition, then your photos may come out unsharp.
Focus Recomposing is when you focus using one, or a group of your AF points in-camera, but rather than taking the photo recompose it into the desired composition, and then take the photo.
[REWIND: PHOTOGRAPHY 101: 3 PRIMARY TYPES OF AUTOFOCUS]
When focus recomposing, choose the closest focus point to your imagined composition. This way, the movement is as minimal as possible. Through this approach, you’re less likely to miss focus than, for example, using an AF point that causes you to recompose at such an angle or distance that you lose your focus.
During the episode, Pye was also asked about Back Button Focusing (BBF), which is when you customize your camera via custom function settings, and assign the focusing button from the shutter button to one of the buttons on the back of your camera.
If you’re using BBF with composites, there’s no need to lock your focus and then switch it to manual focus as you often would in this scenario, in an effort to keep focal plane and DOF consistent, because the only time the focus changes with BBF is when you press the button you assigned it to.
[REWIND: THE ULTIMATE PANORAMIC STITCHING WORKSHOP: INTRODUCTION TO STROBED WIDE APERTURE PANORAMIC STITCHING|
If we have a scenario, where say a model is walking towards the camera, especially in single-shot mode, it becomes more work to press the shutter button and then the back button to capture the photo focus and exposure. However, this is all a matter of preference, and you’ll have to test it for yourself to see how you operate best.
For more tips on focusing modes & tricks for consistently nailing your focus, be sure to check out Photography 101. Become an SLRL Premium member to get exclusive early access to new education & tutorials weekly!