jpeg or tiff from digital cameras

  [DELETED] 01:06 31 Dec 2003


I have read in past postings that TIFF is preferable to jpeg as a medium for saving images due to being lossless. However I believe my recently purchased camera, the Pentax Optio 450 can only save them as jpegs on my pc. I wondered if I was understanding the situation correctly because I have read that even if I initially saved these images as jpegs it would still be beneficial to convert them to TIFFs before editing as there would be no further degradation during the editing process. Is this true? Is it worth worrying about? I only ask because I want to be able to print fairly large pictures at reasonable quality.

Thanks for your help

  ton 02:01 31 Dec 2003

Tiffs are lossless, but they are quite a lot bigger.
Repeatedly editing and saving jpg's does degrade them.
I always keep the original when I edit a photo ('save as' under another name) and you can usually choose high quality when you save as jpg.

  ton 02:14 31 Dec 2003

I don't know what editing software you are using but look for options when you save as jpg as the the highest quality means minimal or no loss.
If you are going to open and edit the file a few times ,then save as a tiff till you are happy with the result, then make the final save as a high quality jpg.

  [DELETED] 08:26 31 Dec 2003

Maybe some experts can tell us more.

I saved a 1.90 Mbyte TIFF image as PNG it was only 1.019 Mbytes. PNG is a lossless format.

I saved the same image as highest quality JPG, it was only 417 Kbytes, but the number of unique colours had been reduced from 30849 to 24964 so though my untrained eye can detect no difference, clearly a lot of information had been lost.

I was using Irfan View.

  Stuartli 08:42 31 Dec 2003

Perhaps some study of the various digital formats would help:

click here

click here

  [DELETED] 09:04 31 Dec 2003

For future reference!!

  [DELETED] 10:19 31 Dec 2003

That page is very well written and informative. I have bookmarked it for future reference. This question is always coming up.

I suggest that PNG is the way to go: decent compression, highest quality, plus alpha channel transparency, and interlacing. I find that PNG images of screen shots can produce more compact and better quality pictures than JPG. One can save even more space by reducing them to 8-bit (256) colours.

JPG 50 (99K) click here (lossy)

PNG (78K) click here (lossless)

PNG (55K) click here (256 colour)

Are there any advantages of TIFF over PNG for saving digital photos?

  [DELETED] 11:56 31 Dec 2003

JPEG is alright for saving an image file direct from a camera, it's only when you start altering or reparing the image you lose quality evrytime you re-save the file. The image is compressed and pixels are then lost which then breaks down the quality of the original image. For digital images etc most of the professional photographers I know work in TIFF or direct from the camera in RAW, TIFF appears to be used the most as no quality is lost.

  Stuartli 12:22 31 Dec 2003

If you just view pix on your monitor or TV screen, then you won't notice much difference whichever format you use to reduce file sizes.

Keep the original file(s) on your system - if you want to send it as an e-mail, using the Send To (mail recipient) reduces it to a .jpeg attachment.

You can then use the original in one of the photo enhacing software programs as normal.

  Demora 12:51 31 Dec 2003

If you save the photos as TIFF and store them on a seperate hard drive or CD/DVD you can make as many .jpg/png copies you you like from the original only losing minimal info. Also if the pictures are on CD etc you avoid losing them if the system goes down.


  Stuartli 16:21 31 Dec 2003

If you open up one of your camera pix in Irfanview and click on the small blue i button in a red circle at the top of the screen, information on how large the pic file is, compression used, resolution figures etc can be found;, clicking on the EHX button details when the pic was taken, with what camera, length of exposure, whether flash was used etc.

On average a medium resolution pic on a 2MP camera will be at least 3MB. This is the foundation on which you work on to convert it to other formats, enhance it and so on.

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