Does ACR 5.7 conversion shrink files using Photoshop Elements 8?

Question

I am using ACR 5.7 (via Photoshop Elements 8) to first process RAW files from my Canon 550D and then convert to JPEG for final tweaking. I have found that the original RAW files are around 20 MEG but the resultant JPEG (even if I do nothing but convert using "open image") is only 880K or something like that. Have I set something wrong? Is there a way to preserve the file size or something similar? Is there a setting to change or should I try reinstalling?

Answer 1

Papa Lesh,
Even though JPEGs get compressed, a factor of 20MB to 880KB is way to much if you didn't crop the image and did not save with a very high compression (meaning very bad quality). This is assuming your image contains data, and is not just 20MB of the same colored pixels.
Example:
If I convert a 15MB RAW (Canon EOS 1Ds) to JPG in PSE8, the resulting JPG is around 9MB in one example. The maths to this is as follows:
- The EOS 1DS RAW is 12 bits per pixel
- The JPEG (uncompressed) is 24 bits per pixel
- 15MB / 12 * 24 = 30MB
- A 9MB JPEG hast been compressed by 66%
Can you post a screenshot of your conversions-settings and/or your JPEG-Options while doing a "Save as" as follows:
Sorry, I can only provide screenshots in German, but I guess you'll see what I mean.
Beat Gossweiler
Switzerland