Canon eos rebel t1i - Manual (Page 72)

3 Setting the Image-recording Quality
72
1 is the raw image data before it is made into a 73 or other images.
Although 1 images require software like Digital Photo Professional
(provided) so they can be displayed on the computer, they also offer
flexibility for image adjustments possible only with 1. 1 is effective
when you want to precisely modify the image yourself or shoot an
important subject.
1 +73 records both a 1 and 73 image with a single shot. The two
images are saved to the card simultaneously. The two images will be saved
in the same folder with the same file numbers (file extension .JPG for JPEG
and .CR2 for RAW). 73 images can be viewed or printed even with a
computer which does not have the camera’s provided software.
About 1
About 1+73
0001 . JPG
0001 . CR2
File number File extension
1 image
73 image
1 , 1+73 and [7 Custom Functions (C.Fn)] menu’s
[High ISO speed noise reduction]
Although the [7 Custom Functions (C.Fn)] menu’s [High ISO speed
noise reduction] (p.185) settings (Standard/Low/Strong/Disable) are
applied to the recorded images, the images are displayed without noise
reduction during image playback (on the LCD monitor and on a TV screen)
or direct printing. (Noise may be noticeable in the images.) You can check
the noise reduction result or print noise-reduced images with Digital Photo
Professional (provided software).
Commercial software might not be able to display RAW images. Using the
provided software is recommended.