Are you sure the jpeg Image Quality setting is the same on both machines … the difference in file size sounds like one of your units is using more jpeg compression than the other. This is controlled by the slider setting found below the Image Format and Include Metadata options … the slider offers levels from 0-12 where the higher the number, the less jpeg compression is applied. I use at least level 10 for most exports … it’s a happy medium between file size and image quality.

The other item to look at is DPI … most folks select 72 for web use, though, you may want to consider setting this higher (depending upon the actual pixel dimensions of the original) for images destined for printing.

To check the setting Butch is referring to go to the bottom of the Export Preset: and select Edit. This will open the Image Export dialog box.
Sounds like the right solution.

A Canon 40D is 10 megapixels. From what I could find via search, the RAW files right out of the camera should be about 12MB. There’s no way the JPEG should be anywhere near that. The 2-3MB size sounds about right for JPEG.

I think the computer that is outputting the larger files is the one with an issue in the output setting. Are you sure you’re exporting a “version” rather than an “original”?

*** Disclaimer - What I am about to share … you are doing at your own risk … I will not be responsible if you lose any settings or suffer additional efforts restoring your settings … even though what I’m sharing is pretty straight forward, bad stuff can happen if you don’t take the proper care. Make sure you have ALL your settings backed up before you do this … also DON“T do this for any plugins because it could cause problems with activations or licensing issues … but it does work well for settings files ***

I do quite a bit of work on location and in the office … so I need my laptop and desktop to be more or less a matched set so I don’t have to make allowances for my normal workflow activities, regardless of where I am working. What I do, is make all my personal settings, preferences, presets and customizations on the iMac desktop computer first … then copy those supporting files to the appropriate location on the laptop. I do this for Aperture, Lightroom, Photoshop, InDesign, and any other apps that I utilize on both computers … that way there is no guesswork at crunch time.

Of Primary importance, for some (not all) situations you must make absolutely sure that you are working with the exact same versions of Apps on both machine, and sometimes even the same exact OS versions … because there can be subtle difference in .plist files you will be transferring.

First, make sure all your default and custom export settings are the way you prefer them on Machine A. Make sure you quit Aperture (on both machines) before you start. Back up the drives on both machines.

Then navigate to:

/Users/username/Library/Application Support/Aperture - (where username is the name for your Mac OS X user account)

The user Library folder in OS X 10.7 and 10.8 is hidden by default … the easiest way to get there is via the Finder menu … In Finder, click once on “Go” in the menu bar, the drop down list will appear, hold down the Option Key, and lo and behold, your Library folder will appear in the list … click on that folder, open the Application Support folder, then open the Aperture folder.

Inside the Aperture folder will be a document called “Export Presets.plist” …drag that file to your other computer (I assume you already know how connect to and see files and folders on computers on your local network) … then replace the corresponding .plist file on Machine B. If you drag and drop it into the proper folder, Finder will ask you if you want to replace the file or keep both … select replace. If you want … you can actually copy the entire contents of this folder to pass over it’s entire settings content. It’s entirely up to you.

Now when you start Aperture on Machine B, you should have a matching set of Export presets that were on Machine A. Both machines should have the proper presets to export identical files.

I make a habit of creating new, often used shortcuts, presets, etc. only on my iMac, then update the Application Support files on my laptop as necessary. Especially just before a big job on the road so everything is matched up and ready to go. So far, it’s worked out quite well.

Daniel,

I can’t understand why you’d want a JPEG file the same size as the original RAW. 10-14MB for a JPEG is way too big for a 10 megapixel image. You don’t need that many megabytes.

Have you compared the two different sized images (after export) on the same computer (i.e. copy the same image exported from one computer to the other) How do they compare? Is there something wrong with the smaller JPEG?

I think we may be getting lost in the jargon or semantics of the situation … I think there may be confusion between megapixels, megabytes and jpeg compression …

For example I took one of my D300s images … it is a 12.2 megapixel camera that records an image 4,288 x 2,848 pixels … If I export an original size 4,288 x 2,848 pixel image as jpeg level 10, the resulting file uses 4.9MB of disc space.

If I export the same exact image at jpeg compression level 6, the file takes up 2.2MB of disk space.

However, when you open both files in Photoshop, the document info data for the file size is the same … 34.9MB … which is roughly the same disk space the image would occupy if it were saved as a single layer uncompressed tiff or psd file, give or take a few MB.

In other words there is the same amount of image data in each file, regardless of the file type saved, it’s just the jpeg file saved at a lower level uses more data compression to store the information. More compression can possibly lead to a higher chance of jpeg artifacts depending upon use.