LV focusing & AF Fine Tune Q?

I have manages to sort out my focusing issues in LV with my Nikon D5300. It was using Wide view' rather than normal view that was causing the problems. Same thing on my Nikon D750. But in doing so I found out that when in Live View any Fine Tune adjustments for a given lens are not used. Why is that or have I got it wrong or is my camera not working correctly.

For example I put the Nikon 105 /f2.8 macro on the D750 that has a +5 AF tune for it with the AF feature tuned on and shoot as per normal and can see in the EXif that the + 5 is registered. I switch to Live View and the EXif shows no + 5 adjustment. Same for all my lens with adjustments.

Live view is a contrast-based autofocus method which uses the imaging sensor directly, rather than a separate autofocus sensor. Therefore, live view doesn't require AF fine-tuning and will not utilize the AF fine tune parameters that you've input into the camera.

Other forum participants with greater technological knowledge than me may provide further details, but that's the basic answer to your question.

John

The camera uses two completely different autofocus systems when shooting in live view vs normal shooting through the viewfinder.  In Live View, AF is done on the sensor plane by the sensor using something called Contrast Detect Auto Focus or CDAF.  Since it is done on the sensor itself, no AF fine tuning is required.  When using the viewfinder, AF is done with a Phase Detect Auto Focus (PDAF) system where a small amount of the light is allowed to pass through the mirror to a secondary mirror which then bounces the light to an AF array in the bottom of the camera.  Since AF is not done on the sensor plane in PDAF, there can be manufacturing tolerances and errors that AF Fine tune attempts to correct.  Hope this helps you to understand the difference and why your AF Fine tune values aren't used, nor make sense to use in Live View.

Yes I do get the gist of it now thanks.

I just have never really used live view beyond the initial novelty of it till necessity dictated I learn how to get the best out of it. I am getting good results now and hope to improve further still before the main orchid season arrives here in Australia.