Jump to content
Jonathan Kingston

Why aren't uncompressed RAW files larger?

Recommended Posts

Just bought an X-T30 and am new to the wonderful world or shooting RAW. I have (what is I suspect) a naive question. Why aren't uncompressed RAW files larger than we see them?

My logic is this:
  X-T30 shoots in 14 bits per channel 3 colour channels. So 42 bits (or 5 1/4 bytes) per pixel.
  Images are 6,240 pixels wide, 4,160 pixels high. 25,948,400 pixels total.
  So I'd expect an uncompressed RAW file to be about 25,948,400 * 5 1/4 bytes big. Or about 130MB.
  But the uncompressed .RAF files come out around 56MB 
Which bit of my assumptions or logic have I got wrong?


Share this post

Link to post
Share on other sites

You are thinking the data is stored as RGB triples, but the camera manufacturers use various ways to pack the sensor data which has the side benefit of compressing the stored files.

Try this: use your favorite raw conversion program to convert one of your raw files and export it as a TIFF file (uncompressed, 16 bit, full quality, etc., etc., etc.) and you will get around 156 MB or so.

Edited by jerryy

Share this post

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...