Canon R6 24-70mm 2.8 lens and 35 sigma art 1.4 lens issues focusing!!

[Just_in15]

Hey guys I’ve been struggling a lot with this recently. Whenever I take a long distance photo on 1.4fstop on a still subject, I use eye detection - AF focus, it always blurs the subject that I am focusing on (i.e. the white square when I half press, it goes green, I shoot and it’s not in focus, on the background is).

this happens with me 24-70mm when I go into 70mm , long distance it’s not as sharp and it’s very soft the subject I am focusing on, but also they’re not focused but the background is.

please someone help me I have struggled with this and I am very disappointed with how my canon journey is going as I cannot get the sharpness I need for my photography 😞

[Waddizzle]

Welcome to the Canon Community. 

Can you post a sample of your issue?  Please share your exposure settings.  

How far away is your subject?  The camera has limits on what it can do. 

[Just_in15]

Hi waddizzle, I especially have this issue when I’m about 3x the distance away from the subject no matter what I do I can’t get the subject in focus. I tap on them multiple times with single focus. I tried servo ai but the blue square goes ballistic even with eye tracking on. They’re clearly in the box when I tap but they are never focused.. sorry I can’t attach a photo but that’s the distance when I’m about triple the lens length away… its really annoying and I think my canon R6 is broken, or my EF mount doesn’t work, or my lens’ just aren’t compatible. Either way I really need to get this fixed or have a solution as I have multiple photo shoots 

[Waddizzle]

My apologies. I still don’t understand how far away you are from the subject. Can you post an image that has the issue?  

[shadowsports]

Greetings,

@just_in15

Are you using a Canon brand adapter with these EF lenses?  Your reply should include sample images with exposure information and focus point display as requested.

[Tronhard]

Hi and welcome Justin:
Can you confirm are both of these lenses Sigma ones or is the zoom one a Canon unit? I note that Sigma do make a lens of the type you mention.  As per my colleague's inquiry, is the adapter a Canon one?  Canon do not and cannot support 3rd party EF lenses directly.  That responsibility comes from Sigma and this page indicates the Sigma EF mount lenses that have been tested and judged compatible for the R6  and both lenses are on the list, but also noting the comments at the bottom:
"We are checking the general operation. We do not guarantee all functions and performance.
As of February 2021, we have confirmed the operation. Please update the firmware of the camera and the lens to the newest version before using this product." 
I suggest contacting Sigma in that respect.
Camera Compatibility | Support | SIGMA Corporation (sigma-global.com)

As regards the work-around you just mentioned, you can try it but it will mean you are shooting in full manual mode for focus and aperture, which rather negates the features of that rather expensive glass.

If you have other lenses does this behaviour occur in them or just the two lenses mentioned?

Finally, are you using tap to focus via the LCD?  If so, can you please turn that feature off along with any face/eye detect, and try focusing via the viewfinder, using single point centre focus?  See if that allows autofocus to work reliably.