5D mk III and microAF adjustment - AI servo only???

eoren1

I just got my camera back from a 'clean and check' at Canon. Had a few stubborn dust spots that I just couldn't get rid of. They also updated the firmware for me.

I took the camera and 70-200/4 IS to the beach yesterday and figured I would test out a few different AF microadjustments in the real world to see if I still needed a +3 on the tele end. Tried out 0, +3 and +5 in the field.

At home, I realized I hadn't installed the Canon ImageBrowser so couldn't see the settings. Did that but only found AF microadjustment showing when AI servo was engaged. Tried it again with my 24-105/4 IS. I put in a +20 on tele and just took three shots - One Shot, AI servo and AI focus. On the back LCD info, only the photo taken in AI servo showed the +20 adjustment :scratch

Can someone confirm this for me? Not sure if this is how it always worked. The AF microadjustment is set to 'by lens' and I am using Case 2 for AI servo if that matters.

*UPDATE: So I figured something out. I use the AF-ON button for focus. If I hold that button in ONE shot mode, the micro adjustment is engaged. If I push til focus confirmation, let go and then click the shutter button, the micro AF does not work...

Thanks
Eyal

eoren1

Got the answer elsewhere. The microAF data is only written to the image during active focus. Since the AF-ON button for focus separates out the two tasks of focus and metering/shutter engagement, the microAF data is not written if the AF-ON is not depressed at the time the photo is taken. The data is still used to achieve the focus though.

ziggy53

Thanks for your research and followup.