Does EXIF tell the focusing distance?

why it only tells the focal length of the lens, but no the focusing
distance?

Thanks

"Rodrigo C." wrote in news:ch7u1q$3vb$1
@news1.nivel5.cl:

why it only tells the focal length of the lens, but no the focusing
distance?


For SLR it might be because the distance is not known.

It might also be because the camera focus in zones.

It might also be because it is not in EXIF.

And it might be because they don't think anyone want it.


/Roland

"Rodrigo C." wrote in news:ch7u1q$3vb$1
@news1.nivel5.cl:

why it only tells the focal length of the lens, but no the focusing
distance?


For SLR it might be because the distance is not known.

It might also be because the camera focus in zones.

It might also be because it is not in EXIF.

And it might be because they don't think anyone want it.


/Roland

Rodrigo C. wrote:

why it only tells the focal length of the lens, but no the focusing
distance?


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-- http://www.aliasimages.com/rpe35mmur.htm
-- e-meil: there's no such thing as a FreeLunch.--

Rodrigo C. wrote:

why it only tells the focal length of the lens, but no the focusing
distance?

If the Focus is encoded in the lens (as well as the FL) then a
calculation of focus plane distance can be done.

Not all lenses (probably damned few) encode the actual focus
setting, and so that is why it does not appear in the EXIF
outputs. (It may be recorded in the file, but if your software
doesn't look for it, it might not come out).

http://it.jeita.or.jp/document/publi...lish/Exife.pdf
Has "subject distance" defined as tag 37382 0x9206 (in TIFF I
believe, not sure if the same convention is used in JPG.)

However, if the lens does not encode the FL, then the subject
distance cannot be computed.

Minolta (D) lenses do encode the focus setting as it is required
for the flash distance integration. Other OEM's also have focus
encoding in their lenses ... but not all them.

(Zoom FL has been integrated for at 15 years and used by the
flash to zoom the flash head and display effective flash range).

Cheers,
Alan


--
-- rec.photo.equipment.35mm user resource:
-- http://www.aliasimages.com/rpe35mmur.htm
-- e-meil: there's no such thing as a FreeLunch.--

Rodrigo C. wrote:

why it only tells the focal length of the lens, but no the focusing
distance?

If the Focus is encoded in the lens (as well as the FL) then a
calculation of focus plane distance can be done.

Not all lenses (probably damned few) encode the actual focus
setting, and so that is why it does not appear in the EXIF
outputs. (It may be recorded in the file, but if your software
doesn't look for it, it might not come out).

http://it.jeita.or.jp/document/publi...lish/Exife.pdf
Has "subject distance" defined as tag 37382 0x9206 (in TIFF I
believe, not sure if the same convention is used in JPG.)

However, if the lens does not encode the FL, then the subject
distance cannot be computed.

Minolta (D) lenses do encode the focus setting as it is required
for the flash distance integration. Other OEM's also have focus
encoding in their lenses ... but not all them.

(Zoom FL has been integrated for at 15 years and used by the
flash to zoom the flash head and display effective flash range).

Cheers,
Alan


--
-- rec.photo.equipment.35mm user resource:
-- http://www.aliasimages.com/rpe35mmur.htm
-- e-meil: there's no such thing as a FreeLunch.--

"Alan Browne" escribió en el mensaje
.. .
Rodrigo C. wrote:

why it only tells the focal length of the lens, but no the focusing
distance?

If the Focus is encoded in the lens (as well as the FL) then a
calculation of focus plane distance can be done.

Not all lenses (probably damned few) encode the actual focus
setting, and so that is why it does not appear in the EXIF
outputs.

but at least my camera (Minolta S414) tells me the focusing distance when
i'm in manual mode (in the LCD), so thats means that the camera in fact
knows that distance and it could be written in the EXIF data.

(It may be recorded in the file, but if your software
doesn't look for it, it might not come out).

yes, may be.


http://it.jeita.or.jp/document/publi...lish/Exife.pdf
Has "subject distance" defined as tag 37382 0x9206 (in TIFF I
believe, not sure if the same convention is used in JPG.)

However, if the lens does not encode the FL, then the subject
distance cannot be computed.

Minolta (D) lenses do encode the focus setting as it is required
for the flash distance integration. Other OEM's also have focus
encoding in their lenses ... but not all them.

(Zoom FL has been integrated for at 15 years and used by the
flash to zoom the flash head and display effective flash range).

I understand, but i'm still thinking that you don't have to encode the focus
setting if we consider what I said about the manual focusing mode (that many
digital cams have, Canon G and S series, A60-70-80 etc..)


Cheers,
Alan

Thank you for your answer
Cheers, Rodrigo



--
-- rec.photo.equipment.35mm user resource:
-- http://www.aliasimages.com/rpe35mmur.htm
-- e-meil: there's no such thing as a FreeLunch.--

In my particular case, Minolta S414, but I've never seen an EXIF tag with
the subject distance (and I've seen a lot of digital photos of many
different cameras)
Do you know any camera that actually have that tag? and very important too..
any software that can read that tag?


Rodrigo


"Jim Townsend" escribió en el mensaje
...
Rodrigo C. wrote:

why it only tells the focal length of the lens, but no the focusing
distance?

Thanks

Which camera and which version of EXIF ?

There are provisions for a distance tag in EXIF.. At least
there is in the later versions. It's up to the camera
manufacturer whether they want to include this information.

Some do, some don't

In my particular case, Minolta S414, but I've never seen an EXIF tag with
the subject distance (and I've seen a lot of digital photos of many
different cameras)
Do you know any camera that actually have that tag? and very important too..
any software that can read that tag?


Rodrigo


"Jim Townsend" escribió en el mensaje
...
Rodrigo C. wrote:

why it only tells the focal length of the lens, but no the focusing
distance?

Thanks

Which camera and which version of EXIF ?

There are provisions for a distance tag in EXIF.. At least
there is in the later versions. It's up to the camera
manufacturer whether they want to include this information.

Some do, some don't

Jim Townsend choreographed a chorus line of high-kicking electrons to spell
out:

Rodrigo C. wrote:

why it only tells the focal length of the lens, but no the focusing
distance?

Thanks

Which camera and which version of EXIF ?

There are provisions for a distance tag in EXIF.. At least
there is in the later versions. It's up to the camera
manufacturer whether they want to include this information.

With my Canon EF lenses that record distance information, BreezeBrowser can
display the focus distance in the EXIF information, but none of the other
programs I use to edit pictures reads that particular tag...

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