Digital image compression question

Comments

• Reply 1 of 4

  roduk Posts: 706member

  October 20, 2002 7:29AM

  The compression doesn't affect the resolution, but it does affect the overall image quality. On most cameras, by default the images are stored as JPEGS. The JPEG compression algorithm is lossy, in that image quality is sacrificed in order to obtain smaller file sizes.
  
  
  
  <a href="http://ei.cs.vt.edu/~mm/gifs/jpgs.html"; target="_blank">This</a> shows an image at various levels of compression.
  
  
  
  With higher compression, there are larger blocks of the same colour, giving the impression of a lower resolution in certain areas of the image.
  
  
  
  [ 10-20-2002: Message edited by: RodUK ]</p>
• Reply 2 of 4

  proxy Posts: 232member

  October 20, 2002 10:01AM

  Hi Gobble gobble,
  
  RodUK has it pretty much covered. The only reason I can see to use anything other than best quality is to fit more images onto the CF card, but with the prices being so cheap at the moment I'd go out and buy at least a 64MB and preferably a 128MB card. The only other reason to use the lower settings is if you are only going to use the pics for email or web..then you could pick 800x600 and high compression rates as it could save you some time (though iPhoto does it supremely well anyway).
  
  If I remember rightly, the JPEG format throws away more and more of the colour information as you compress it (someone confirm that?) so stick to biggest files that your camera can output. Very, very nice camera by the way.
  
  
  
  Proxy
• Reply 3 of 4

  proxy Posts: 232member

  October 20, 2002 10:07AM

  oops ..double post
  
  Proxy
  
  
  
  [ 10-21-2002: Message edited by: Proxy ]</p>
• Reply 4 of 4

  gobble gobble Posts: 615member

  October 20, 2002 10:24AM

  Thanks - I just changed the compression from fine to superfine. Not sure if I'll be able to see the difference but I'll keep my eyes open.
  
  
  
  GG