Go Back   Steve's Digicams Forums > Digicam Help > General Discussion

Thread Tools Search this Thread
Old Jun 26, 2004, 10:24 PM   #1
Senior Member
aladyforty's Avatar
Join Date: Jan 2004
Posts: 6,964

Just trying to make sense of this metadata

1. what does upper left under orientation explain?

2. what is YCbCr positioning ?

3. and what is colorspace??

hate to sound stupid here but Im wondering about these in the metadata below.

Make Canon
Model Canon EOS 300D DIGITAL
Orientation upper left
X resolution 180
Y resolution 180
Datetime 2004:06:26 15:59:49
YCbCr positioning centered
Exposure time 1/100 s
F-number 7.1
ISO speed ratings 100
Date/time original 2004:06:26 15:59:49
Date/time digitized 2004:06:26 15:59:49
Component config YCbCr
Shutter speed value 0.010000 s
Aperture value 5.65564
Exposure bias value 0
Max. aperture value 4.97086
Metering mode Pattern
Focal length 55 mm
User comment
Colorspace sRGB
Pixel X dimension 3072
Pixel Y dimension 2048
Focal plane X res. Unknown
Focal plane Y res. Unknown
Focal plane res. unit inch
Sensing method One-chip color area sensor

aladyforty is offline   Reply With Quote
Sponsored Links
Old Jun 26, 2004, 10:48 PM   #2
Senior Member
Onyx's Avatar
Join Date: Jan 2004
Posts: 402

1. Your camera most likely has an orientation sensor that detects when you hold the camera vertically for example take a portrait image. "Upper left" simply means the left hand side of the camera was oriented upwards ie. you held the camera's right side grip downwards (which I personally find more awkward than the other way, but anyhow...)

2. No idea.

3. Colourspace is basically describing the range of possible colour values the sensor grabs in an image. sRGB is standard Red Green Blue. The camera sensoris sensitive only to the 3 diff colours corresponding to these 3, all other intermediate colours are determined by the combination of the 3 sensors' colour values. There's basically 2 predominant colourspace: sRGB and aRGB (Adobe RGB - named after the software company infamous for Photoshop).

Summary of the metadata you posted:

You used your new camera, a Canon EOS300D. It was held vertically, left side up. You took an image at ISO100, with shutter speed 1/100s. And as I understand it,you set the aperture value at f/7.1, however the camera decided (against your will/knowledge) to have it at f/5.6 when exposing the image. You used evaluative (pattern) metering, and fully zoomed in the 18-55mm kit lens. It was taken at the full 6MP resolution of the camera.

Onyx is offline   Reply With Quote
Old Jun 27, 2004, 4:38 PM   #3
Join Date: Apr 2004
Posts: 76

1) http://jpegclub.org/exif_orientation.htmlhas a very good explanation.

2) To convert the RGB data to YCbCr (which is the common used format for JPEG), the YCbCr positioning decribes how the color data is used (centered: the center point is used). Please note, that even modern cameras still use a color sub sampling!

3) The most complicated subject ever and impossible to describe in detail on a few pages. The colorspace describes how the color values are mapped to colors of a defined device. sRGB is acolorspace that works for most devices.

BTW: cPicture ( http://cpicture.de/en ) has the most detailled meta data displayed and illustrate the orientation in the display.
Jurgen Eidt is offline   Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

All times are GMT -5. The time now is 4:54 AM.