Focusing distance info in RAW file

[Carlos Lindado]

Hello, I'd like to know if there's a way to know the focusing distance in a picture shot in RAW. I was looking at the metadata of various RAW files in DPP, but they don't provide focusing distance.


I'm interested in this because I want to replicate a shot I made some days ago, but using a different lighting, and I'm not able to get the same focus of the original shot.


(If this feature doesn't exist, don't you think it would be a useful feature?)

[neuroanatomist]

Jan and I had a conversation about this previously, when he posted EXIF distance info with a shot. Adobe Lightroom reports distance.


It seems that one specific distance is not recorded with the EXIF data - there are two values, Focus Distance Upper and Focus Distance Lower. I can see those with a Terminal (command line in Windows-speak) tool on my Mac. It looks like Lightroom does some sort of calculation on those values to estimate a subject distance, or just uses one of the values.





Looking at some of my own shots, the actual focus distance falls in between the two of them, a little closer to the Lower value (I save my LensAlign Pro AF microadjustment shots - and for those, I actually set a specific focal plane to test target distance with a tape measure).


It seems that DPP uses these data for lens aberration correction - in the Tune dialog box of the aberration correction section, there's a 'shooting distance information' slider. However, that's useless as the only marking on the slider is∞ at the right side; there are no actual numbers there.


Furthermore, when you use DPP for RAW conversion, it actually strips theFocus Distance Upper and Focus Distance Lower fields from the EXIF data! They are there in the RAW file, but not in the resulting JPG.

[Sheiky]

Yep we did have this conversation and I found out that the focus distance is also visible in Windows 7's picture-info of jpegs. It looks quite right to me. But after the lens's focussing screen goes to infinity it starts showing the weirdest focus distances. So for instance the 70-200 F4L IS shows focussing distances in it's screen ranging from 1.2m/4ft to 10m/30ft and after that it starts to go to infinity. So as far as I've seen, the focus distances reported are pretty believeable from 1.2m to 10m, but after that point they start playing funny. So it's depending on the lens you have.