Distance to target in focus not provided in EXIF: why?

Why is the distance to target in focus NOT provided in the EXIF? Focal length, apperture, shutter speed, all go from lens to camera and make their way to the EXIF. Why not distance to target?

I have been asking this same question for months. Still no satisfactory answer. I believe EF lenses do not report distance info to the body. But I could be wrong.

Probably because the camera has no way of knowing the distance to the target. It would be different if the camera calculated the distance to the target for focusing purposes but it doesn't. The scale on the lens (if it has one) does give an indication of the distance of the object to which it's been told to adjust focus to.

wickerprints wrote in post #8328659
I have been asking this same question for months. Still no satisfactory answer. I believe EF lenses do not report distance info to the body. But I could be wrong.

Some do, most all the newer ones do...

Yes, I'm sure I've read somewhere that although most lenses do report the focus distance to the camera, the current EOS bodies don't record it in the Exif simply because Canon's own software has no use for the information.

would be dead usefull in astrophotography
Distance to target: 84.5 light years xD

gofer wrote in post #8328673
Probably because the camera has no way of knowing the distance to the target. It would be different if the camera calculated the distance to the target for focusing purposes but it doesn't. The scale on the lens (if it has one) does give an indication of the distance of the object to which it's been told to adjust focus to.

Neither has the camera a way to know the focal length...unless the lens reports it to her. When I change the focal length ring on the lens, the camera knows it and registers it. Why not the same happens when I change the focus ring?

this is where some noink will come in and say "theirs do"

As Kenji said, many/most of the newer lenses do report distance to the camera and it is available somewhere in the EXIF. When using a flash in ETTL, that information is sent to the flash to use in calculating the flash exposure. How to get at it is another matter.

In DPP, if you go into lens aberation correction, there is a distance slider that matches the actual distance set when the image was taken depending if the lens reported it.

PS. I haven't used DPP in ages..... this appears to no longer work in that all my lenses show infinity whereas in previous versions of DPP it appeared to show, relative to the scale, the correct distance, at least with some of my lenses.

How about the real question...

Why does it matter?

So we don't see question such as... my 400mm is soft when taking pictures of objects 2 feet away

it doesnt does it.... unless you work for achitects - but then they should know....

Could be interesting but not very useful and no I do not know why not. Will be more useful to have for external flash especially when used off camera.

I don't think the technology is up to it. For something within 50 feet, maybe, there is a lot of lens travel, but once it get's out there, the lens only moves in micro adjustments to focus where there are hundreds or thousands of feet of difference, or as mentioned, light years.

I can't really know exact distance to subject but it can and does know at what distance the lens focused. At the very least that should be in EXIF. The lens I used and its focal length setting is already there when the lens supports such information, so there's really no technological reason for the focus distance to not be reported under the same conditions.