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DPChallenge Forums >> Photography Discussion >> 400D in RAW mode: odd picture sizes
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 12/14/2008 04:50:09 PM · #1
Hi all,

I'm seeing some odd behaviour with my Canon 400D in RAW versus "RAW + LargeJPEG". The file sizes and image dimensions are different (depending on who you ask). I'm hoping I've missed something obvious here.

If I shoot a test scene in "RAW + LargeJPEG" I end up with two files: a 12-14Mb CR2 image and a 3-4Mb JPEG, and I can fit around 100 shots on a 2Gb card. If I switch to RAW only, the .CR2 file is 8-9Mb, and I can fit ~190 on the same card.

So, why the difference in file size? I'm shooting the same scene and suddenly we go from 12Mb to 8Mb for the RAW image.

If I view the CR2 images in Irfanview (which I use to sift through shots) it identifies the CR2 from the RAW-only shot as 1936x1288, and the CR2 from the RAW+JPEG as 3888x2592. Canon's EOSUtility software says both CR2 files have the same image dimensions. Weird.

Any ideas?

Cheers
Buzzy

Message edited by author 2008-12-14 16:50:40.
 12/14/2008 07:45:33 PM · #2
Some of the cameras now have a "small RAW" option, too. Could that have to do with it?
 12/14/2008 07:51:47 PM · #3
Originally posted by Beetle:
Some of the cameras now have a "small RAW" option, too. Could that have to do with it?


Thanks for the suggestion Beetle. As far as I can tell there's no option on the 400D, but I'll have a check through the menus. The settings all list the image dimensions, and RAW-only claims 3888x2592 when you choose it.
 12/14/2008 08:11:02 PM · #4
there is no sraw option on the 400d.

I guess its a screwy peice of software, if it is as you say that the files ARE the same size regardless of what Irfanview says.
 12/14/2008 09:32:51 PM · #5
Okay, I've done a bit of research (yay Google). It looks like RAW mode embeds a JPEG image (1936x1288 pixels) in the .CR2 file to help applications preview the file more quickly. My guess is the "RAW + large JPEG" mode embeds the full size JPEG (3888x2592) in the .CR2 file as well as saving it as a separate file.

This would explain why Irfanview is reporting smaller image dimensions in RAW-only mode, because it's rendering the small JPEG. This would also explain why the .CR2 file size is different - because "RAW" means "RAW with a small JPEG embedded" compared to "RAW + large JPEG" which is "RAW with a large JPEG embedded"

I'll go check this with Photoshop's RAW converter tonight.

Message edited by author 2008-12-14 21:52:53.
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