Exchangeable Image File Format (EXIF)

The Exchangeable Image File Format (EXIF) is a de-facto standard (it has never been ratified by any standards organization such as the International Standards Organizaion, ISO, or the American National Standards Institute, ASNI) that specifies the formats for images, sound, and ancillary tags used by digital cameras (including smartphones), scanners and other systems handling image and sound files recorded by digital cameras. The specification uses the following existing file formats with the addition of specific "metadata tags": JPEG for compressed image files, TIFF for uncompressed image files, and RIFF WAV for audio files, and IMA-ADPCM for compressed audio data).

EXIF was created by the Japan Electronic Industries Development Association (JEIDA). Version 2.1 of the specification is dated June 12, 1998, and the latest, version 2.3 dated April 2010, was jointly formulated by JEITA and CIPA. Though the specification is not currently maintained by any industry or standards organization, its use by camera manufacturers is nearly universal.

I should note that "metadata tag" is a typically grandiose and un-evocative computer "science" term for something very simple. The "data" in a JPG, for example, is the data for the picture. "Metadata" ("meta" [from a Greek word meaning "after," "beyond," "with," "adjacent"] is a prefix used in English [and other Greek-owing languages] to indicate a concept which is an abstraction from another concept, used to complete or add to the latter) is some data that has been added to the main data. "Tag" is computerese for a "field" (computerese for "space" ) in a file format into which you can "enter" (computerese for "type" ) any darn thing that strikes your fancy. One example are the metadata tags in the MP3 format. There are quite a few of them but mostly "artist," "title," "album," and "genre" are used by media player libraries and portable media players (PMPs) to organize MP3s. The MP3 standard allows anyone who has a tag editor to type in anything, according to no standard, with no consistency checking, and with no spell checking, anything they want in Unicode (which means one can see MP3s with tags in English (ASCII which means you may or may not see the accent-e in Beyonce and Celine Dion), Cherokee, Hebrew, Chinese, Aramaic, Korean, Armenian, and (in some of Bjork's) Icelandic!

Although EXIF data is appended to these internally recognized standard file formats, this adding is not an official part of these standards. In other words, Japanese manufacturers put in EXIF data on their own lookout and so, they can do so any darn way they please.

Problems

Apart from not being a maintained standard, the EXIF format has a number of drawbacks, mostly relating to its use of legacy file structures.

o The derivation of EXIF from the TIFF file structure using offset pointers in the files means that data can be spread anywhere within a file, which means that poorly written software (most software is buggy) is likely to corrupt any pointers or corresponding data that it doesn't decode/encode. For this reason most image editors damage or remove the EXIF metadata to some extent upon saving.

o The standard defines a MakerNote tag, which allows camera manufacturers to place any custom format metadata in the file. This is used increasingly by camera manufacturers to store myriad camera settings not listed in the EXIF standard, such as shooting modes, post-processing settings, serial number, focusing modes, etc. As this tag format is proprietary and manufacturer-specific, it can be prohibitively difficult to retrieve this information from an image (or properly preserve it when rewriting an image). Some manufacturers encrypt portions of the information; for example, Nikon encrypts the detailed lens data in their newer MakerNote data versions.

o The standard only allows TIFF or JPEG files — there is no provision for a "raw" file type which would be a direct data dump from the sensor device. This has caused camera manufacturers to invent many proprietary, incompatible "raw" file formats. To solve this problem, Adobe developed the DNG format (a TIFF-based raw file format), in hopes that manufacturers would standardize on a single, raw file format.

o The EXIF standard specifically states that color depth is always 24 bits. However, many modern cameras, such as the Nikon D70 which captures 36 bits of color per pixel, can capture significantly more. Since EXIF/DCF files cannot represent this color depth, many manufacturers have developed proprietary, non-compatible Raw image formats.

o Some digital cameras can also capture video. The EXIF standard has no provision for video files.

o EXIF is very often used in images created by scanners, however the standard makes no provisions for any scanner-specific information.

p Photo manipulation software sometimes fails to update the embedded thumbnail after an editing operation, possibly causing the user to inadvertently publish compromising information.

o EXIF metadata is restricted in size to 64 kB in JPEG images because according to the specification this information must be contained within a single JPEG APP1 segment. Although the FlashPix extensions allow information to span multiple JPEG APP2 segments, these extensions are not commonly used. This has prompted some camera manufacturers to develop non-standard techniques for storing the large preview images used by some digital cameras for LCD review. These non-standard extensions are commonly lost if a user re-saves the image using image editor software, possibly rendering the image incompatible with the original camera that created it.

o There is no way to record time-zone information along with the time, thus rendering the stored time ambiguous.

p There is no field to record readouts of a camera's accelerometers or inertial navigation system. Such data could help to establish the relationship between the image sensor’s XYZ coordinate system and the gravity vector (i.e., which way is down in this image). It could also establish relative camera positions or orientations in a sequence of photos.

o Because the EXIF tag contains information about the photo, it can pose a privacy issue. For example, a photo taken with a GPS-enabled camera can reveal the exact location it was taken, which is undesirable in some situations. By removing the Exif tag with software such as ExifTool before publishing, the photographer can avoid possible problems.

o In the original release of Windows XP, a subset of the EXIF information may be viewed by right clicking on an image file and clicking properties; from the properties dialog click the Summary tab and then the Advanced button. However, this accessing can damage certain EXIF headers if changes are applied. As of the release of Service Pack 3, Windows XP still shows evidence of corrupting EXIF tags when modifying JPG file properties via the file properties window

That being said, you can safely access the EXIF data without corrupting it if you use one of the many software tools available which allow both viewing and editing of EXIF data. The Opanda IExif Viewer is a free stand-alone application for viewing Exif data and also a plug-in for Internet Explorer and Firefox on Windows platforms. EXIFeditor is another free application that allows editing of EXIF information. It allows examination of detailed Exif data online by right clicking on an image. FxIF and Exif Viewer are multi-platform extensions for Firefox that display Exif data in the image properties dialog. This feature is native in the web browser Opera, under image properties.

If one of these tools does not allow you to see a "distance" tag, you can go low-tech and get a little spiral notebook and make notes about your photos as you take them in the field. Note that the battery in a pencil never dies, a pencil never runs out of ink, and you can use a pencil in zero gravity! And you can get Adobe Lightroom if you want to "tag" your photos according to your own system.

Here is the best list I could find of all the current metadata tags in my Cannon camera. There is a lot more stuff in EXIF than one typically sees, but I don't see "distance" in there anywhere. If you get an EXIF viewer/editor, you might find that Nikon kooged EXIF to include distance. If so, I don't think you can fault Microsoft for not complying with Nikon's non-standard use of a non-standard!

Manufacturer
Model
Orientation (rotation)
Software
Date and Time
YCbCr Positioning
Compression
x-Resolution
y-Resolution
Resolution Unit
Exposure Time
FNumber
ExposureProgram
Exif Version
Date and Time (original)
Date and Time (digitized)
ComponentsConfiguration
Compressed Bits per Pixel
Exposure Bias
MaxApertureValue
Metering Mode
Flash.
Focal Length
MakerNote
FlashPixVersion
Color Space
PixelXDimension
PixelYDimension
File Source
InteroperabilityIndex
InteroperabilityVersion

Anybody that has used CS5 (maybe others, I don't remember) has the reading in the exif data.
It is the called the "Subject Distance". It is the distance the camera focused on.

I have used it in the past to satisfy my curiosity. :-)

On to the question, have you tried otehr programs to see if it is being recorded by the camera?
If you know someone that you can have read the original file.
You would then know if it is the camera or the software.
Just an idea,

Gordon

Distance to a camera is not logged in or calculated by any camera that I'm aware of. This is an excellent question and is one worth answering.

Someone asked why do you want this information? There are many good reasons for calculating and logging distance between a camera and a subject. Perhaps the most important reason for needing this information is for consistency. Knowing how far away a subject is from the camera is important if you want to repeat the pose or shot and make a specific type of shot repeatable in any situation. Unfortunately the only way to achieve this is to do a physical measurement by using a tape measure or other measuring device and "Make" a physical record by writing it down on a piece of paper.

Distance information is critical if you want consistency in doing photography if you're doing portraiture or want to achieve repeatable affects when taking photos. No camera on the market creates accurate "Distance" metadata for any kind of photography, whether it's still shots, or video. That is probably because it's a bit complicated to incorporate into a camera and the complex algorithms would limit the camera's abilities and make it more complex to use than is really necessary.

In answer to the question, no there is not any metadata recorded into your camera for distance when you take photos. You need to do this physically by measuring the distance between your subject and the camera and then write and keep this information in a logbook. Hope this helps answer your question. I don't think this resolves your problem, but it might be a solution you're seeking.

One other suggestion: If you're shooting photos with a telephoto and your subject is a fair distance away, is to use a "spotting scope." Many expensive spotting scopes and a few of the economical ones have distance calculations built in and you can estimate the distance between you and a subject through the spotting scope. It doesn't provide accurate distance right down to the inch, but provides a close estimate on how far away a target is located. That's important information many hunters use, or people that do target practicing in order to achieve more accurate shots. It might actually be a good device to use in photography, but it's not one I've ever found a need to try.