birding-aus

Digital cameras and authentification of images

To: <>
Subject: Digital cameras and authentification of images
From: "Colin Driscoll" <>
Date: Sat, 21 Feb 2004 09:21:37 +1100
Hi

Most if not all modern digital cameras record a lot of information about the
image. Generally these are EXIF files. A simple image handler (free) is
Irfanview http://www.irfanview.com/ and you can use the Image information
enquiry to see this info

Here's an example of the EXIF data attached to an image a colleague sent to
me. If the image had been modified there would be a difference between the
original dates and the date in the main info panel.

ImageDescription -
Make - RICOH
Model - CaplioG3 modelM
Orientation - Top left
XResolution - 72
YResolution - 72
ResolutionUnit - Inch
DateTime - 2004:02:12 12:04:09
YCbCrPositioning - Co-Sited
Copyright - (C) Caplio G3 modelM User
ExifOffset - 616
ExposureMode - Auto
WhiteBalance - Auto
SceneCaptureType - Standard
Sharpness - Normal
ExposureTime - 1/250 seconds
FNumber - 5.50
ExposureProgram - Normal program
ISOSpeedRatings - 125
ExifVersion - 220
DateTimeOriginal - 2004:02:12 12:04:09
DateTimeDigitized - 2004:02:12 12:04:09
ComponentsConfiguration - YCbCr
CompressedBitsPerPixel - 2.00 (bits/pixel)
ApertureValue - F 5.66
BrightnessValue - 7.70
ExposureBiasValue - 0.00
MaxApertureValue - F 2.46
MeteringMode - Multi-segment
LightSource - Auto
Flash - Not fired, auto mode
FocalLength - 5.70 mm
UserComment -
FlashPixVersion - 100
ColorSpace - sRGB
ExifImageWidth - 960
ExifImageHeight - 1280

Out of interest these original dates and times can be matched back to the
dates and times of downloded tracks of a GPS running at the same time as the
picture was taken and the coordinates of the location can be determined.

Cheers
Colin Driscoll

> -----Original Message-----
> From: 
>  Behalf Of Robert Inglis
> Sent: Saturday, February 21, 2004 7:44 AM
> To: 
> Subject: [BIRDING-AUS] Digital cameras and authentification of images
>
>
> Hi all,
> In his posting of Fri, 20 Feb 2004 10:39:03 +1100: Re: coxens fig
> parrot, Peter Fuller made the
> suggestion:
> "I urge all birders to get a digital camera and take it with them
> in the field for just this type of
> situation.
>
> Digital technology is a godsend for birders and birds, in my
> opinion.  If you see a species that is
> rare, a vagrant, or different in anyway, digital cameras
> (combined with the internet) makes it
> simple to capture an image of the bird, record its call and send
> it to colleagues to confirm
> identification."
>
> While this is an excellent suggestion and ideal for the
> particular circumstance which prompted
> Peter's comment, it should be noted that images from most digital
> cameras may not be acceptable 'in
> a court of law' unless they can be proven to be 'original'.
> That is to say that the image has not been altered,
> inappropriately changed or enhanced in any way.
> Digital images can very easily be changed to show practically
> anything you would like them to show.
> A recent example would be the falsified photos of one of the
> candidates in the current American
> presidential 'race'.
> In that case elements from two photos were combined to produce
> false 'evidence' of the candidate's
> supposed association with another person.
> The 'trick' was only exposed when the person who took one of the
> original photos came forward.
>
> Apparently there is software available which can be used in
> association with the digital camera
> which will indicate the authenticity of the originality of the
> digital image but I think this
> software is camera-specific and is only available for a limited
> range of camera models.
> It is unlikely that there would be any 'consumer' digital cameras
> with this associated software and,
> in fact, very few digital SLRs with it as well.
>
> My point is:
> By all means carry a suitable digital camera for the purpose of
> recording photos of birds for later
> confirmation of identification.
> Digital images are available for viewing immediately and are very
> easy to distribute.
> But be prepared to face a battle if you wish to use the images as
> proof of existence of a rare
> species especially in a law court.
>
> Cheers
> Bob Inglis
> Woody Point
> Queensland
> Australia
>
>
>
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