JPEGs and compression

Discussion in 'Photography' started by airtas, Feb 18, 2009.

Thread Status:
Not open for further replies.
  1. airtas

    airtas Member

    Messages:
    23
    Likes Received:
    0
    Trophy Points:
    0
    this may be a dumb question but a jpg/jpeg is compressed correct?


    so if you do a RED Eye fix and then save does it get compressed again?

    what about rotation?
     
  2. CalebSchmerge

    CalebSchmerge Super Moderator/Reviewer News/Review Writer

    Messages:
    884
    Likes Received:
    9
    Trophy Points:
    0
    Everytime you open a JPG and change something it will be recompressed. That is the risk with using a JPG file - they can be degraded rather quickly.
     
  3. airtas

    airtas Member

    Messages:
    23
    Likes Received:
    0
    Trophy Points:
    0
    even if the edit is within the camera?
     
  4. CalebSchmerge

    CalebSchmerge Super Moderator/Reviewer News/Review Writer

    Messages:
    884
    Likes Received:
    9
    Trophy Points:
    0
    More than likely yes. There are ways around this issue, but I very highly doubt that the camera is implementing them. The lower the compression you use (higher quality) the less this will affect it. A two fold increase in compression will be at least a two fold decrease in cycles before visible degradation, I think.
     
  5. airtas

    airtas Member

    Messages:
    23
    Likes Received:
    0
    Trophy Points:
    0
    I think on my kodak camera when I took vertical shots it automatically kept it rotated but on my canon it keeps it horizontal no matter what

    is this common?
     
  6. CalebSchmerge

    CalebSchmerge Super Moderator/Reviewer News/Review Writer

    Messages:
    884
    Likes Received:
    9
    Trophy Points:
    0
    Both my Canon and Nikon (point and shoot and DLSR) will auto rotate. The Nikon isn't recognized right by Windows, but lightroom handles everything perfectly.
     
  7. airtas

    airtas Member

    Messages:
    23
    Likes Received:
    0
    Trophy Points:
    0
    what do you mean auto rotate?
     
  8. CalebSchmerge

    CalebSchmerge Super Moderator/Reviewer News/Review Writer

    Messages:
    884
    Likes Received:
    9
    Trophy Points:
    0
    If I shoot in a portrait vs. landscape orientation, the camera can sense that and will bring the picture into the computer in the proper way - so that I don't have to rotate the pictures my self.
     
  9. leaftye

    leaftye Well-Known Member

    Messages:
    269
    Likes Received:
    0
    Trophy Points:
    0
    The problem isn't just that it is compressed, the problem is that it is compressed with a loss of information. I prefer lossless compression like that found in png files.
     
  10. airtas

    airtas Member

    Messages:
    23
    Likes Received:
    0
    Trophy Points:
    0
    does kodak and canon rotate differently?
     
Thread Status:
Not open for further replies.

Share This Page