Raw Exif Focus points

[birdboy]

I thought some of you may be interested in the following RAW exif data I have been able to work out for the OMD-EM1. It may apply to other models as well.
Sometimes when I take a picture using AF all focus points the camera decides which point to choose. If you take the picture in RAW the exif contains metadata (AFAreas) and gives some numbers. By taking a number of pictures using single AF point I have been able to work out what those number mean and which point it used to focus on.
It would be useful if anyone could validate this information for me. It may be available elsewhere but I could not find it.

Hope you find this useful.

John
MFT 81 points



FT 37 points

[Gwyver]

Re: Raw Exif Focus points

John,
By some strange coincidence I am currently trying to analyse how C-AF performed on some series of images and whilst looking to see if OV3 displayed AF location I chanced on Graham of Rainham's recent post which re-awoke your thread.

Looking at the numbers in your tables.
It appears that for the purposes of AF selection the image area is mapped onto a 256x256 array, and that the numbers you have shown for each AF location correspond to a rectangle (roughly 23w x 19h) within the array.