Canon RF 28-70mm f/2.8 IS STM Focus Tracking Issues - Detecting Wrong Subjects in Group Shots

[janmike80]

Hi, having upgraded from my old Tamron 24-70 G2 f/2.8 to the RF 28-70 f/2.8 IS STM, I'm underwhelmed by its tracking performance with people. For example, when there's a group of clients, the focus tends to detect the back of someone's head in the frame rather than the faces facing the camera. Is there a solution in the camera settings, or are there firmware updates that can fix this? During my corporate events, it's making me crazy.

I don't want to downgrade to my old Tamron—it's heavier, and I'm on 8-hour shifts.

[lijarey179]

Yeah, the RF 28-70 IS STM can be hit-or-miss with tracking, especially in group shots. Try switching to Servo AF, use zone focus, and turn on "People" detection also disable Preview AF. No lens firmware updates yet, but tweaking those settings should help a lot.

[p4pictures]

Since the subject detection is a function of the camera body, not the lens. Can you tell us which camera you are using?

Also what do you have selected for the following focus settings.

• AF area or method 
• One-shot or Servo AF
• Preview AF (may be called continuous AF on some cameras)
• Subject to detect
• Eye detection 
• Whole area tracking Servo AF
• Are you using back button focus, or the shutter to focus

Sorry that's a lot, but it will help us try to work out a solution. 

[janmike80]

Hi, basically in all modes—One Shot, etc.—but worst is Servo AF. Yesterday I was taking candids of a group that were talking, like 4-5 people. Two were perfectly exposed with faces towards the camera, while others were facing the two guys who were talking. Guess what? The AF locked on the guy's back of the head.

The situation here is that they were correctly exposed—no need for flash, etc. I have my back button set to eye focus detection, and the shutter button was set to normal people detection (no eye detection), just people's heads. I pressed the back button for eye detect... BAM, back of the head. Pressed shutter—same thing. Switched to One Shot and just used good old single focus point, got the shot.

But this defeats the purpose. Having used my Tamron 24-70 G2, I had no issues like this. But like I said, I bought this lens thinking it was going to be a better experience, mostly for my use case and less weight. I REALLY hate the thought of mounting the Tamron again.

[janmike80]

Tomorrow i got another gig, i will try this thanks!.

[janmike80]

Tomorrow i got another gig, i will try this thanks!. disable Preview AF? where is that in the canon r6 could not find it in menus.

[p4pictures]

On the EOS R6 (original / Mk1) the menu item is Continuous AF, it was renamed Preview AF on later cameras. You can find Continuous AF on the AF1 menu and it should be set to disable. 

Since you have an EOS R6, then I hope you know that the camera can only track faces when it is set to one of these AF methods; 

• Face + Tracking AF
• Zone AF
• Large Zone AF: Vertical or Horizontal

If you are using Face+tracking AF method, then you might chose to set an initial AF point for use with servo AF. In effect this gives you an AF frame that is similar in size to the 1-point AF frame and you can use it to "target" a specific face in a group of people. 

Be careful with setting the AF-ON to initiate Eye AF, as doing this means that the camera will not have an initial AF point so the camera simply picks a head / eye among the group for you. 

[janmike80]

yes inital af pt for FACE af, on got back button now setup for face tracking using a custom AF ON BUTTON REGISTER / RECALL with only face detection on tracking: sens-acell at default and af operation on, moddified my * button to EYE AF AND left shutter button for using small square zone af.
Continuous AF was is allways off.

so 3 buttons with distinct AF modes. Lets see what happens tomorrow.