This is most likely caused by entropy coding, which is the final lossless stage of JPEG compression, after the image data has been quantized to reduce its size.
When a JPEG image is losslessly rotated, this final lossless encoding layer must be undone, the unpacked DCT coefficients shuffled around, and then the shuffled coefficients need to be entropy coded ...
In short: there is no reason to care about this value and it its presence does not make your file larger.
identify -verbose filename(s)
only displays the quality if the image uses the standard quantization matrix. You can use nonstandard matrix (-define jpeg:q-table=...) to make this value disappear.
The quality will be, however still displayed when the (...
I went ahead and repeated the experiment to see if I could figure out what's going on.
I generated a random 256-by-256 pixel RGB image using the "Solid Noise" filter in GIMP (Filters > Render > Clouds > Solid Noise...) using the default settings (shown below):
And the result:
Then I saved the image as a JPEG using the default settings:
Then I ...
There isn't really any surefire way, other than meticulous bookkeeping, or following consistent habits.
Use your mobile phone to take images of the rear LCD info page showing the file name for the first and last image each of you take each time you operate the camera. For instance, if you take a dozen pictures, when you're done shooting for a ...
From the man page:
Short output format. Prints tag names instead of descriptions.
Add up to 3 -s options for even shorter formats:
-s - print tag names instead of descriptions
-s -s - no extra spaces to column-align values
-s -s -s - print values only
exiftool -s -s -s -...
Well, for one thing, all photos larger than 16 megapixels are resized to 16 MP — so, for many cameras today, that's an immediate, obvious drop in resolution.
But all other photos are compressed too, using an optimizing compression algorithm. I don't think Google comes out and says exactly what they do, but it's probably their open source Guetzli algorithm. ...
The Exif:ApertureValue is stored as an APEX value as mandated by various EXIF standards.
The APEX system is a way to calculate exposure and works using base-2 logarithms. The use of base-2 means a rise of one in the value equates to a doubling, which we know as 1 stop; which makes it pretty handy for photographers if they're good with logarithms (which we ...
EDIT: This answer was posted before I knew that the files had increased in size by around 9 KiB (9055 bytes for the 256×256 image, 9612 KiB for the 512×512 image).
In all likelihood, when you first rotated the image, Windows Picture Viewer did one (or both) of the following things:
Added an EXIF tag that was not in the original JPEG image (perhaps the ...
Using ExifTool, ShutterSpeed is not an actual tag within the file, it's a tag derived from several other values (See Extra Tags). That's why it's grouped under Composite Tags when you follow ExifTool FAQ 3.
As you discovered, the actual tag you want to write to is EXIF:ExposureTime using ExifTool.
Yes, it is possible. But you should not do this. Being dishonest with your teacher is never a good move. If you have a mirrorless interchangeable lens camera with a large sensor, you may be able to convince your teacher that what you have is significantly close to a DSLR to work for the needs of the class. It's probably a good idea to ask exactly what she's ...
I suggest using the excellent exiftool by Phil Harvey:
exiftool -TagsFromFile fromImage.jpg toImage.jpg
See also questions 8 and 9 at the Exiftool FAQ if you're copying tags between certain RAW image formats (shouldn't be a problem if you're copying between JPEG images).
When the engineers are designing a lens, the 70-300 is a target focal range they design to, but it's not important that they hit it exactly as long as it covers the advertised range. As they tweak the lens characteristics to get a suitably sharp and quality image for the target cost, the actual focal lengths may change slightly. Eventually, when everything ...
I don't know what is required to recognize the "foreign" image, probably something in the Exif... but for your goal, just create the image with your message, with appropriate background, and take a picture of it when showing on the home computer screen. Then it is already in the camera.
Irfanview and jhead will both do what you want.
Links to both below.
jhead is command line driven or can be called by other processes.
Irfanview version can be invoked from a command line or internally in a batch or on a file by file basis.
Example below for Irfanview shows how to copy in either direction:
Allows GUI or command line ...
ExifTool is pretty much the Swiss army chainsaw for doing these kinds of things. It has a steep learning curve, but once you're over it, the kind of renaming you're after is a snap:
exiftool -d '%Y%m%d-%H%M%%-03.c.%%e' '-filename<CreateDate' .
The -d switch tells ExifTool to format dates according to the next argument's pattern. The pattern contains ...
Those appear to be codes from a Fuji Frontier automatic film processing lab machine or one of its older predecessors. Such machines were/are popular at mass retailers who did/do one hour photo processing and printing.
Users have some leeway in assigning what information is printed using the codes on the back of the print, so there is some variation ...
Nikon D3400 (and, I assume, other models) lets you select the active folder to store files in. Just change folders when you change photographers.
More generally, you can use two memory cards and change cards when you change photographers.
For whatever reason, the ColorSpace tag is not very useful in EXIF. The only standard values are 1 (sRGB) and 65535 ("uncalibrated"). All other values are reserved. Some cameras use them to mean Adobe RGB or something else, but this is non-standard. Apple is, in fact, using Something Else, and that's found elsewhere in the metadata. With ExifTool, looking ...
Experimentally (on my EOS 70D), this is the beginning of the exposure, and not the end.
this seems truncated to the second
it depends how accurate is the time of the camera (before doing this I carefully set the time on my camera, but I doubt I can do better than half a second)
... not speaking of clock drift if it hasn't been set recently
IMHO a ...
You are confused because ApertureValue and MaxApertureValue are APEX values, not F-stops.
An F-stop of 1.8 is equivalent to an APEX aperture value of about 1.695994. (The formula is Av=log₂A², where Av is ApertureValue and A is f-number. See
the Wikipedia APEX system page for a full explanation.)
Some exif readers (like ExifTool) convert these to F-stops ...
It is sadly impossible to to prove when an image (or any file for that matter) originated. It is possible (if the author wants to) to prove that a file existed prior to a given time by signing the file from a third party time stamping server (through which the third party proves that the file existed at the time of the signing) but such information is not ...
ExifTool is a cross-platform tool which will work from the Windows command line. It is very powerful, with a perl-based syntax allowing comparison of various metadata. In a directory full of JPEG files, this command
will print a list of all files where the beginning of the filename does not match the year from the date-taken EXIF value:
exiftool -d "%Y" -...
This isn't metadata that can be stripped. It's an analysis of the compression calculated from the quantization tables. When it's comes back unknown, the jpeg was compressed using a program that isn't known to identify.
See this SuperUser answer.
Edit: Upvotes for @szulat answer, much more detailed than mine.
One solution that might work if you don't switch too frequently:
Take a selfie whenever you take the camera.
Then you know all following pictures have been made by the person of the most recent selfie. (Maybe you should think about a "sign" if you do frequently take pictures of eachother.)
I did this at a previous job, where we first also used to keep a ...
Your camera saves this information, which we call "metadata" (because it is data about the data captured in the photo itself — one level beyond, or meta), in every file. There are many utilities which can read and display this. I'm not aware of any software designed for photography which doesn't — that'd include Adobe Photoshop and Lightroom, Picassa, and ...
As the author of StolenCameraFinder, I am somewhat biased ;)
Both sites have published success stories. Here are my success stories, and here is one from CameraTrace. I actually have more stories in my email, I'm just pretty rubbish at typing them up ;)
With both sites, you can run searches for free manually, just try them out and see what results you get. ...
You can use exiftool to remove the orientation tag:
exiftool -Orientation= /target/dir/or/File
Replace /target/dir/or/File with the files and/or directories you want to process. If run under Unix/Mac, use single quotes to avoid bash interpretation.
To suppress the creation of backup files, add -overwrite_original.
To recurse into subdirectories, add -r.
The EXIF standard describes the DateTimeOriginal tag simply as "the date and time when the original image data was generated." It gives no guidance about what event (e.g., shutter released, shutter open, shutter closed, sensor read, post processing) should be used to determine the value.
As mentioned in a comment, the best way to find out how your camera ...
Good news, this is now natively supported in Picasa
Tools > Options > Name Tags > "Store Name Tags In Photo"
You can also force Picasa to start the writing process using
Tools > Experimental > "Write Faces to XMP"
Verify this worked with using an EXIF viewer to verify a normalized XMP region with a name was written to the ...