How to interpret EXIF "Approximate Focus Distance "

[msoomro]

When I look at the file properties in PS I see a parameter ApproximateFocusDistance with long number. Is there a way to read what this number means. I could not find a parser online. Tried couple EXIF viewers but they were no help. Please advice


<aux:ApproximateFocusDistance>4294967295/1</aux:ApproximateFocusDistance>

 

[AlanLichty]

I have never utilized this EXIF parameter but some online info for that particular item gets a wide range of responses. The particular value you have above converts to "ffffffff" hexadecimal and would effectively represent infinity as far as your camera was concerned. Most numbers are expressed as two values such as 585/100 which would work out to 5.85 meters.

From things I could find online it would appear that this is pretty specific to nikon cameras with nikon lenses or canon cameras with canon lenses. Canon may use this for flash synchronization with their ETTL-II metered flash.

Useful links:

https://www.dpreview.com/forums/post/33786590

http://www.uglyhedgehog.com/t-343636-1.html#5767274

 

[JimFox]

That's interesting. Approximate focus distance? I don't usually pay much attention to the Exif except for when viewing older shots to try and remember when I shot them.

Jim

 

[msoomro]

I was trying to experiment with approximate focusing distance for optimum sharpness vs focus stacking. Wanted to see which of my focus points estimate for a scene was better. With the D850 Focus Stacking, i started thinking what parameter guides the camera to move focus point and by how much. Upon examining EXIF my eyes caught this parameter which seemed relevant.

@AlanLichty Thanks for the pointers.