Tuesday, September 27, 2016

Exif 2.31 sucks just a little bit less

This summer JEITA released Exif version 2.31.  The good news is that this version finally addressed the long standing issue of missing time zone information in Exif.  They also tried to add six tags related to the shooting situation, but unfortunately these were less well thought out:

Temperature - This is meant to store ambient temperature.  While this is potentially informative, cameras typically do not measure ambient temperature very well because they are usually warmer than their environment because they are being held by warm hands.  A sensor temperature measurement would be much more useful because this may be used to select the dark frame for noise removal from astronomical images.

Humidity - I applaud the idea, but I've never seen a camera that measures this.  This could potentially be very useful for FLIR cameras (forward-looking infra red) because they need this measurement for an accurate calculate of atmospheric attenuation in determining the blackbody temperature of the subject.

Pressure - Air pressure in units of hPa.  Good idea.

WaterDepth - Water depth in metres.  Negative is above water level.  Nice.

Acceleration - Directionless acceleration in units of mGal (10^-5 m/s/s).  This is of limited usefulness.  Why not include a proper 6-axis acceleration?

CameraElevationAngle - Nice, by why only one angle.  What not a 3-axis Pitch, Roll and Yaw?  These angles are very useful for many applications, yet still missing from Exif.

I guess I should be happy that Exif is not dead, and that JEITA is at least continuing to expand the specification, but it would be nice if they listened to the metadata community and not just the camera manufacturers when developing the standard.

Friday, May 1, 2015

I'm pissed off at Leica.  Yet again they mess up their maker notes for the new M Monochrom (Typ 246) camera.  I wish they would just pick a scheme and stick with it.

Thursday, March 31, 2011

Dirty Rat Bastards

Samsung is playing dirty with the metadata of its NX10 camera. While other manufacturers like Nikon and Sony encrypt colour balance information in RAW images (presumably to prevent 3rd party RAW converters from using this information), Samsung has taken this to another level with the NX10 (and various other recent models):

The difference is that the stored information is actually usable, but is changed just a little bit by adding small, random encrypted amounts to the stored values. The effect would be that the images wouldn't be as good from 3rd party utilities using this information.

Nasty.

But the next version of ExifTool (8.54) will remove this obfuscation from the stored values.

Chalk up one for the good guys.

Friday, March 26, 2010

More Windows corruption woes

Yet again I get a question from a user with images that have been corrupted by editing metadata with Windows. The biggest problem is that Windows may change the byte order of the EXIF when the metadata was edited. This is a REALLY, REALLY BAD thing to do because it is impossible to properly change the byte order of some proprietary information. So the effect is that this information is corrupted, causing errors when other software that parses this information reads the image.

This was a problem with Windows XP up to and including Service Pack 3, but from one report this seems to have been fixed in Vista and Windows 7. If so, there must still be a lot of people running XP out there because I keep seeing this complaint.


Wednesday, March 24, 2010

First confirmed XMP in original images

I think I now have enough samples to conclude that Canon is embedding XMP into images directly from the camera. Currently the XMP contains only a single tag, "Rating", which has a value of 0 in all my samples. While I thought there was a chance that all of my samples had been modified by some Canon software utility which added the XMP, I have now obtained enough samples from different sources that I believe this is not the case. The samples I have with XMP are from the following PowerShot models: A3100IS, SD980IS, SD1400IS, SD3500IS and SX210IS.

This is significant because in the past the limitations of EXIF have forced camera manufacturers to store information in a proprietary format in images, limiting its usefulness. But now that manufacturers are embracing XMP there is a chance that some of this information could be put in a more useful format.

For instance, it would be GREAT if cameras like the Panasonic DMC-ZS7 stored its location information (Country, City, State, etc) in XMP. Currently this information is stored in the maker notes, which means it is unavailable to most software. (The only reasonable option with the maker note solution is to use ExifTool to copy the information to XMP, which is one of the very useful functions of ExifTool, but in an ideal world this would not be necessary.)

Monday, March 22, 2010

More web server stats

I spent some more time watching the ExifTool web server to see what was getting the most traffic. The most popular file is the "ExifTool Updates" RSS feed, which gets an average of about 2.3 hits per minute -- that's 100,000 hits per month (from more than 20,000 unique IP's). Due to the nature of RSS, I was worried about this file dominating our bandwidth, so I tried to keep it small (12 kB) and set its reload period to 90 minutes (for RSS readers that honour the TTL attribute). Good thing I did that.

Tuesday, March 16, 2010

ExifTool download statistics

I just checked the web server to see how many people are downloading exiftool. I am now getting more than 1000 downloads per day from the main server. This doesn't include all of the downloads from the various CPAN mirrors and other download sources (which all together could easily be another 1000 per day).

At this rate I could retire with a $40,000 per year salary if I just charged $0.05 per download.

But ExifTool is free.