EOS R1 loses focus while using a burst having AF Servo with Flash

[DhandaNot]

I have been using Canon R1 with 600EX-RT for some macro photography of live insects at night which needs the flash. I have set the camera to have slower burst of about 5 shots per second. This allows the flash to work for several shots.

What I notice is that focus is achieved but as the flash happens, the camera loses the focus and then needs time to acquire focus again. Then misses it again on a flash.

As such very few images in the burst are actually in focus. I tried a few times and believe this is a true description of what I am experiencing.

I would like to understand from others if they have done something similar and what was their experience.

I also look forward to comments from Canon Experts.

[deebatman316]

How dark is it when you’re taking pictures. What lens are you using? Why are you using Servo AF are the insects moving? If they’re barely moving One Shot is the best choice. If it’s too dark the camera will not achieve focus and still fire the shutter in Servo AF. In One Shot this won’t happen because there is focus lock. There is no focus lock in Servo AF like One Shot. Also the camera or Speedlite can’t emit an AF Assist Beam in Servo AF. The AF Assist Beam only works in One Shot. If it’s too dark the speedlite will fire Intermittently to assist the camera with AF. The IR AF Assist Beam IS NOT COMPATIBLE with Mirrorless cameras. Depending on the ambient lighting conditions the camera may project an LED AF Assist Beam.

[DhandaNot]

I am using 100L F2.8 Macro with R1. The time was night but the diffuser I use has led light enough to illuminate the subject. The subject could be still but also moving. I am talking about the case where the subject is moving. Examples would be a Praying Mantis that is moving on a a flower / branch or a scorpion devouring a prey.

I use back focus button so if the subject is still I let the camera achieve focus and then I let the button go. This effectively is Single shot focus.

To elaborate further when I am shooting that moving praying mantis / scorpion I can see that the camera misses the focus after the flash.

[deebatman316]

Is that lens the EF or RF Mount version. Are you using the Flash in E-TTL or Manual. Are the pictures out of focus when you review the pictures. Please post example pictures in the forum.

[LeeP]

Fascinating. I am often astounded by the sheer knowledge of people here. I enjoy learning. Thank you for this information.

[Waddizzle]

“ Fascinating. I am often astounded by the sheer knowledge of people here. I enjoy learning. Thank you for this information. “

Me, too.  We might have to start calling Demetrius “The Flash.”

[deebatman316]

Some people here do call me the flash expert when it comes to Canon’s flashes and flash system.

[LeeP]

I am acutely aware that my Canons have an astounding level of capacity that my head has not gotten itself around in totality. Thus, I am appreciative of the knowledge base. An R1 isn't even on my list because of the expense, but if someone gave me one as a retirement present in a year, I would be thrilled. Again, much appreciation to you.

[deebatman316]

Maybe I should add to my signature "- EOS Flash Expert". I get so many flash questions and PM's from new users in the forum regarding speedlites or how E-TTL works. Then which new or used flash is the best for them.

[LeeP]

Maybe we need a tab "Demetrius Talks Flash" and put your tutorials there.