RAW File conversion question

When exporting a version in Aperture 3, there is a drop down list in the Export dialog box. You can select to export to JPG, PNG, TIFF, etc along with the image dimensions of the file.

 

jpeg is a compressed file format - RAW is all the original information

JPEG is known as a lossy compression format in that some information is thrown away - you can decide on how much information is thrown away allowing you to trade off quality for file size.

Try outputing the same file as TIFF and you will see the file size grow enormously , because TIFF keeps all the information but stores it in a less efficient.

its all a bit like the difference between an MP3 audio file and a CD AIFF file

each has there uses, but you never get something for nothing - the smaller the file size the less the ultimate quality

K

 

Actually I think TIFF comes in several flavors, some of which feature lossless compression - to pursue your metaphor, that would be WAV versus AIFF ;-)

 

you are right some if not all TIFF formats use a lossless compresion - LZW if i recall

if two or more succesive pixels have the same values then that info can be stored in less bits of information

high iso noisy files are always bigger than low iso smooth files.


I was working in the software industry in the early days of desktop publishing and spent a lot of time explaining things like scanning and resolutions...this was back in the day when i was working with macs with 20MB hard disks.... yup... not even enough space for a single Canon 5d Mk2 image

changed days indeed

K

 

Kevin, when you embed here do you tend to do it through Flickr as opposed to the gallery and which kind of file are you exporting from Aperture?

I drag my photos from the library view onto the Flickr uploader and that's that... When I do put them in a gallery here I export the size 1024 x 1024, I believe it is. I haven't uploaded any RAW files here in a long time, however.

 

bb

i almost always link from my flickr page - where the images are there at 50% sized JPEGS - i normally post here with the medium sized version of the flickr file - which i think is half the size of the full flickr image. Working back from the original 4000 x 3000 pixels of the file out of the camera I post a 2000 x 1500 sized file to flickr and a 1000 x 750 to here

cheers

K

ps... thanks for the nice comments on my flicrk page