File size output from a 10 MB RAW file?

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Level 1

21 points

File size output from a 10 MB RAW file?

What is the file size that Aperture generates when a 10 MB RAW file (.CR2) is published at 300 dpi, original size using highest quality settings?

The reason I ask this is because Aperture seems to publish files from my Canon 5D Mk2 which are shot at highest RAW quality (~24 MB) to JPEGs which are also in the same file size range i.e. 24 MB. However, using the same above settings, when I publish RAW files which are of lesser file size, say 10 MB (.CR2), Aperture publishes it at ~3-4 MB JPEG file size, and not in the 10 MB JPEG range. Why the difference?

I use lots of my images for selling on stock sites where the minimum uncompressed file size requirement is 24 MB. And I have lots of images which are at ~10 MB RAW file size, which I am unable to use becuase they dont meet the minimum file size criteria. Ideally, a 10 MB .CR2 RAW file should create a compressed JPEG file of ~10 MB, however it does not seem to be the case.

Can someone help? thanks in advance.

MacBook Pro, Mac OS X (10.7.1), Intel Core i7, 4 GB RAM, 500 GB HDD

Posted on Oct 29, 2012 10:17 AM

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Answer 1

hibhaven Author

Level 1

21 points

Nov 8, 2012 9:12 AM in response to hibhaven

mmm, 10 days, 36 views and no response:(

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Answer 2

Aye Es Oh

Level 2

330 points

Nov 8, 2012 9:30 AM in response to hibhaven

Not entirely sure I know what you're after, but any JPEG, even on maximum quality settings, is going to be a fraction of the size of an original RAW file. You might want to see if the site where you're submitting the image will take TIFF or perhaps PNG files, which will not be nearly as compressed.

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Answer 3

Nov 8, 2012 9:47 AM in response to hibhaven

JPEG compression is all over the map. Going for a file size in MB with a JPEG is totally nonsensical. Try the quality settings and you'll see for quality 10, 11, 12 you may see file sizes of 3 MB, 6 MB, and 18 MB (or something), with no visual differences you can see.

Uncompressed (TIFF) is different: There's an exact file size for a given megapixel size (and depending on whether it's 16 bits or 8 bits per pixel).

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Answer 4

Aye Es Oh

Level 2

330 points

Nov 8, 2012 10:09 AM in response to Aye Es Oh

Exactly. File compression works by throwing away redundant data. JPEG compression changes an image to increase redundancy, whereas PNG's compression does not change the image, it only attempts to find what is redundant and describe where that redundancy is. Either way, a compression algorithm's resulting file size will vary greatly depending on image content.

For example, the file size of a PNG for a computer-generated illustration is much smaller than a photo that has been compressed with PNG, since the computer-generated illustration has more areas of solid color, and thus more redundancy.

Aperture's flavor of TIFF is uncompressed, although other programs do offer various compression methods.

This site has an interesting comparison of various compressed image file formats: http://www.sitepoint.com/gif-png-jpg-which-one-to-use/

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