Fine tune focus method for zoom lenses?

[c22w1]

If you are doing fine tune adjustment for say a 70-300mm lens what would be the best focal length to use? 70mm, 300mm or at some midpoint? I'm finding out that the settings are different throughout the range and can't keep adjusting for each one?
Thanks

 

[cotty332000]

If you are doing fine tune adjustment for say a 70-300mm lens what would be the best focal length to use? 70mm, 300mm or at some midpoint? I'm finding out that the settings are different throughout the range and can't keep adjusting for each one?
Thanks

Which focal length do you use most?
Set it for that,otherwise you will have to calculate an af fine tune value that is a compromise!
I think some cameras are able to save different af fine tune values for the same lens at different focal lenghts!

 

[c22w1]

I use it mostly at the longer end, for which it is correctly calibrated (I enjoy bird photography etc) but I was at my daughters graduation last week and used it at the mid point, the results were very disappointing and obviously now can't be reshot. Gutted is not the word when I looked at the shots on a big screen.