jt Posted April 27, 2007 Share Posted April 27, 2007 I've just been preparing files for printing and noticed something strange: the JPG files from my Canon 350D are 3456x2304 pixels, but RAW files are 3456x2298 pixels. Is this 'normal'?? It's certainly a bit of an inconvenience in that I have to crop all the RAW files slightly to get the aspect ratios 'correct'. Can anyone shed any light on what's going on? (Using Aperture to import, but I can't imagine that's the cause of the issue - does anyone have experience with other software (my camera is being repaired at the moment)) Thanks, Jonathan. Link to comment Share on other sites More sharing options...
ronald_moravec1 Posted April 27, 2007 Share Posted April 27, 2007 Six pixels could fall on the floor and you won`t find them. Link to comment Share on other sites More sharing options...
mendel_leisk Posted April 28, 2007 Share Posted April 28, 2007 I noticed one program (Raw Shooter Essentials?) that could extract an extra 5~10 pixels in both directions. Canon's software, and most others, produce the advertised dimensions from the raws, but there are a few extra pixels around the edge that can be salvaged. Link to comment Share on other sites More sharing options...
steve_dunn2 Posted April 28, 2007 Share Posted April 28, 2007 <p>If you look at the specs for the camera, you'll find that the total number of pixels is different from the effective number of pixels. I have a 20D, and the specs say it has approximately 300 000 of these extra pixels (it has approximately 8.5 million total pixels, but only 8.2 million "effective" pixels). Since the perimeter of the image is 11 680 pixels, that means that the sensor itself has an extra 25 pixels or so on each side (on average, anyway).</p> <p>As Mendel mentioned, the sensor has extra pixels on it that don't appear in the final image. I've seen a number of explanations as to why they're there; the one that seems to make the most sense to me (which doesn't necessarily mean that it is or is not true) is that the Bayer interpolation algorithm needs to have data from nearby pixels in all directions, so the pixels which make up the edge of the final image have to have pixels around them on the sensor itself.</p> <p>If that Bayer explanation is correct, then those extra pixels have to be included in the RAW file as well, so that the RAW converter has access to them so that it can do the interpolation correctly. And so if the folks who write a particular RAW converter want to do so, they can use some of those extra pixels to make a slightly larger image, or cut the image back down a bit. It's also entirely possible that whoever wrote the 350D code for Aperture mistakenly shaved a few pixels off the size of the images it produces.</p> Link to comment Share on other sites More sharing options...
fanta Posted April 28, 2007 Share Posted April 28, 2007 For the records, a conversion from Canon EOS 350D RAW made with Adobe Lightroom comes up with 3456x2304 pixels. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now