Cameras record a ton of information about the exposure settings of your camera, and these have been standardized into EXIF metadata fields. What few people realize is that metadata is not limited to these standard fields, and your camera is recording far more information than you ever thought possible.
Much of this extra data is thrown away when a RAW file is processed because it isn’t decoded by the software that processes the raw data. The resulting image file will only have the standard fields of information like aperture, ISO, shutter speed, lens model, serial numbers, GPS information, etc. While this seems like a lot of information, there are key values that get stripped away.
Take for example the above image. It was photographed with the Canon 1D X Mark II and the Canon MP-E 65mm lens which records the lens magnification factor in a special metadata area known as “maker notes”.
This value is incredibly useful if you want to measure the size of something in the photograph. This data disappears from your final image, as well as other interesting bits of information such as the camera’s internal temperature, whether or not the image is an in-camera multiple exposure, if the image is part of a bracketed sequence, if High ISO Noise Reduction is turned on, and much more.
While these values might not be useful in every day scenarios, I hate to throw any information away. What if I’m diving into a noise analysis of my images, for which the camera’s internal temperature affects noise? What if I wanted to if the image was captured using Live View or a Viewfinder?
Take a look at the data that is stripped out of a RAW file, or a camera-generated JPG file that hasn’t been touched by an editing program. This is a sample of what gets destroyed:
Time Zone : -04:00
Time Zone City : New York
Daylight Savings : On
Bracket Mode : Off
Bracket Value : 0
Bracket Shot Number : 0
Raw Jpg Size : Large
WB Bracket Mode : Off
WB Bracket Value AB : 0
WB Bracket Value GM : 0
Macro Magnification : 1.0x
Live View Shooting : Off
Focus Distance Upper : 0.24 m
Focus Distance Lower : 0.24 m
Flash Exposure Lock : Off
Internal Serial Number : DK0013700
Exposure Level Increments : 1/3-stop set, 1/3-stop comp.
ISO Speed Increments : 1/3 Stop
AEB Auto Cancel : On
AEB Sequence : -,0,+
AEB Shot Count : 7 shots
Spot Meter Link To AF Point : Enable (use active AF point)
Safety Shift : Disable
Same Exposure For New Aperture : Disable
Usable Shooting Modes : Disable; Flags 0x3f
Usable Metering Modes : Disable; Flags 0xf0
Exposure Mode In Manual : Specified metering mode
Shutter Speed Range : Disable; Hi 1/8192; Lo 32
Aperture Range : Disable; Closed 91; Open 1
AE Microadjustment : Disable; 0; 8; 0
FE Microadjustment : Disable; 0; 8; 0
Focusing Screen : Ec-CV
View Info During Exposure : Disable
LCD Illumination During Bulb : Off
WB Media Image Size Setting : Rear LCD panel
Viewfinder Warnings : Monochrome, WB corrected, One-touch image quality
Continuous Shooting Speed : Enable; Hi 14; Lo 6; 5; 3
Continuous Shot Limit : Disable; 99 shots
Restrict Drive Modes : Disable; Flags 0xbf; 1
Custom Controls : 0 1 0 0 2 0 2 0 2 0 2 6 0 8 0 0 0 0 2 0 0 0 2 0 0 0 0 0 0 0 255 255 0 3 112 48 0 0 0 0 0 0 0 0 0 0 0 20 80 0 0 0 0 7 0 0 255 255 255 0 255 255 255 31
Dial Direction Tv Av : Normal
Av Setting Without Lens : Disable
Multi Function Lock : Off; Quick control dial
Lock Microphone Button : Protect (hold:record memo); 31
Add Aspect Ratio Info : Off
Timer Length : Disable; 6 s: 0; 16 s: 6; After release: 0; 16; 0; 2
Short Release Time Lag : Enable
Memo Audio Quality : High (48 kHz)
Default Erase Option : Cancel selected
Retract Lens On Power Off : Enable
Aspect Ratio : 3:2
Cropped Image Width : 5472
Cropped Image Height : 3648
Cropped Image Left : 0
Cropped Image Top : 0
Tone Curve : Standard
Sharpness : 3
Sharpness Frequency : n/a
Sensor Red Level : 0
Sensor Blue Level : 0
White Balance Red : 0
White Balance Blue : 0
Color Temperature : 5200
Picture Style : Standard
Digital Gain : 0
WB Shift AB : 0
WB Shift GM : 0
Measured RGGB : 382 1024 1024 922
VRD Offset : 0
Sensor Width : 5568
Sensor Height : 3708
Sensor Left Border : 84
Sensor Top Border : 50
Sensor Right Border : 5555
Sensor Bottom Border : 3697
Black Mask Left Border : 0
Black Mask Top Border : 0
Black Mask Right Border : 0
Black Mask Bottom Border : 0
Color Data Version : 13 (80D)
WB RGGB Levels As Shot : 2589 1024 1024 1544
Color Temp As Shot : 7397
WB RGGB Levels Auto : 2589 1024 1024 1544
Color Temp Auto : 7397
WB RGGB Levels Measured : 2589 1024 1024 1544
Color Temp Measured : 7397
WB RGGB Levels Daylight : 1886 1024 1024 1606
Color Temp Daylight : 5200
WB RGGB Levels Shade : 2158 1024 1024 1398
Color Temp Shade : 7000
WB RGGB Levels Cloudy : 2024 1024 1024 1502
Color Temp Cloudy : 6000
WB RGGB Levels Tungsten : 1346 1024 1024 2325
Color Temp Tungsten : 3200
WB RGGB Levels Fluorescent : 1589 1024 1024 2212
Color Temp Fluorescent : 3643
WB RGGB Levels Kelvin : 1886 1024 1024 1606
Color Temp Kelvin : 5200
WB RGGB Levels Flash : 2081 1024 1024 1473
Color Temp Flash : 6352
Average Black Level : 2048 2048 2048 2048
Per Channel Black Level : 2048 2048 2048 2048
Normal White Level : 13535
Specular White Level : 14888
Linearity Upper Margin : 10000
Custom Picture Style File Name :
AF Micro Adj Mode : Disable
AF Micro Adj Value : 0
Vignetting Corr Version : 0
Peripheral Lighting : On
Chromatic Aberration Corr : On
Peripheral Lighting Value : 1
Original Image Width : 100
Original Image Height : 1331
Peripheral Lighting Setting : On
Chromatic Aberration Setting : On
Peripheral Illumination Corr : Off
Auto Lighting Optimizer : Off
Highlight Tone Priority : Off
Long Exposure Noise Reduction : Off
High ISO Noise Reduction : Low
Multi Exposure : Off
Multi Exposure Control : Additive
Multi Exposure Shots : 0
AF Config Tool : Case 1
AF Tracking Sensitivity : 0
AF Accel/Decel Tracking : 0
AF Point Switching : 0
Sub Sec Time : 89
Sub Sec Time Original : 89
Sub Sec Time Digitized : 89
Flashpix Version : 0100
Exif Image Width : 5472
Exif Image Height : 3648
Focal Plane X Resolution : 3805.285118
Focal Plane Y Resolution : 3807.933194
Focal Plane Resolution Unit : inches
Custom Rendered : Normal
Exposure Mode : Manual
Scene Capture Type : Standard
Continuous Drive : Continuous, High
I’ll be the first to admit that I don’t know half of those values are, and much of the other half don’t concern me terribly much. This data is generated via Phil Harvey’s excellent ExifTool software, which can pull out every bit of hidden metadata there is to find, and some of this deleted information can be very valuable.
Imagine if Lightroom could tell if your camera was in Continuous shooting mode, detect at what frame-per-second value you were shooting at, and then look at the timestamp of your images to auto-stack your bursts together. What if I was able to sort my photos based on macro magnification, or create a smart collection that contains all of my bracketed shots or multiple exposure images? What if I shoot different subjects with different AF settings, and can then organize my images based on this? There are a lot of scenarios where this data can become useful for organizing large catalogs, but Adobe doesn’t decode it and considers it garbage data.
Even if the data isn’t decoded and used for anything, an in-camera JPG contains all of this information. As soon as that JPG is edited in Adobe software, the data is lost once again. There is likely more data that isn’t currently being decoded properly that you’ll never see in your final edited images.
This should serve as a public letter to Adobe and other companies like Corel, Phase One and ON1:
Even if you do nothing with this special camera-specific metadata, don’t destroy it so that others cannot make use of it. Just leave this section of the image file intact for the potential benefit of everyone. ExifTool is simply a Perl library with a command-line front end that anyone can use to see this information if they want to, and I would be a better organized photographer if my software made use of it.
Make use of this metadata goldmine, or at least leave it for others to explore. Stop destroying my metadata!
P.S. For those curious, the image featured in this article was created using a Gerbera Daisy and invisible ink, and was lit with a specially modified flash that only emits ultraviolet light.
About the author: Don Komarechka is a nature, landscape, and macro photographer based in Barrie, Canada. His macro work has been highlighted in international publications. Don is an author, educator, and adventurer with a passion for revealing “the unseen world”. Visit his website here.
from PetaPixel http://petapixel.com/2016/05/21/adobe-discards-valuable-metadata-processing-raw-files/
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