How to force Apple Mac OS-X to recognize Canon PowerShot S90 raw files (CR2)
How to make Aperture recognize Canon PowerShot S90 raw files (CR2)

The following is my little contribution to the users of Canon PowerShot S90 who want to take advantage of this camera ability to shoot raw files, and who want to use a Mac running Apple Aperture to edit, file and manage their pictures.

Apple does make some excellent products, but there are some issues with some of them that really frustrate me. For example the Macintosh operating system, Mac OS-X as it is called, has build-in support for the raw images produced by digital cameras. In other words, if your digital camera is in the cameras supported by Mac OS-X, the raw files produced by that camera will be useable by every application that runs under Mac OS-X or at least by any Apple application.

As some of you already know, I own a Canon PowerShot S90 camera (and a couple of Nikons) and I am using an iMac and a MacBook, running Aperture, to manage my pictures, edit and file them. In the Nikon world, I always shoot raw (NEF, and being a lucky man my cameras are supported by Mac), so I wanted to do the same with my S90. I like the way Aperture works and I am not going to invest the money required to buy Adobe Photoshop, nor the time required to learn it.

Unfortunately, the Canon S90 is NOT supported by Apple. While their latest operating system version was released much after the Canon S90 hit the market, Apple didn't include the S90 in the supported cameras. They did however include the PowerShot G11, a camera that has the same censor as the S90. Knowing that, and from what I read on the Internet, that the raw files had to be similar since those cameras are using exactly the same censor, I decided to do some research to "convince" Mac OS-X to recognize the S90 raw files. An internet search brought up a solution, which patched some of the Mac system software files, which unfortunately didn't work for me, for some strange reasons. So I had to come up with an other method, if I wanted to shoot raw with my Canon.

Here is what I came up with.

Mac software checks a "tag" inside the CR2 raw file (CR2 is the extension of the raw files, as they are produced by Canon cameras) to figure out what camera a picture is shot with. That tag is called "CanonModelID", and that's the only tag that needs to be changed, to allow Mac to understand and use the pictures you shoot with the S90. All you have to do, is change that tag in your CR2 raw image files, to something that your Mac OS-X already supports. In this particular case, I decided to change the tag to show "PowerShot G11" instead of "PowerShot S90", the reason being of course, that the G11 and the S90 share the same censor (as stated above), so the image information would be interpreted correctly by any program in the Mac (who would be fooled to believe the file has been shot with a G11 camera, instead of the S90).

To change the tag, I used a program called ExifTool, written by Phil Harvey which you can download for free. ExifTool allows you to see the various tags found inside a raw file, but it also allows you to change them! Just what the doctor ordered in this case. ExifTool is a command-line tool (meaning there is no GUI interface, so you can only run it through a Terminal window in Mac OS-X. Remember the good old MS-DOS days?) and that's a good thing, because as a command-line program, it supports all Unix wild characters. That means that you can convert all your S90 images, with one single command.

The procedure I came up with, is this:

I first copy all my .CR2 files, from the S90 memory card to a temporary folder I have created on my Desktop, called "Canon_Conversion" (you can call it whatever you want, of course). So I end up with a group of .CR2 files in there. Then I open a Terminal window and move into that folder, where I issue the following command:

exiftool -canonmodelid='PowerShot G11' *.CR2

What that command does is:

- it copies all original .CR2 files to new files which have the same name as the originals, but they have an extension ".CR2_original" instead of ".CR2". In that way your initial files are preserved.
- it then patches a copy of each original file, replacing the contents of the "canonmodelid" tag (which was "PowerShot S90" before) with the string "PowerShot G11".

So you end up with two set of files, one with extension .CR2 (patched files) and another with extension .CR2_original (your original files). The .CR2 files are now perfectly readable by Mac applications, such as the Finder, Aperture, Xee etc, which believe that the files were shot with the supported Canon G11 camera instead of the S90.

All I have to do now, is to move the .CR2 files in my standard Master files directory structure and import them in Aperture, where I can edit them to my heart's content. The funny thing is that Aperture still reports that the camera model is "Canon PowerShot S90" in the Exif Viewer, LoRL. Please note that now, your finder shows you the pictures just as if they were .jpg files, or any other supported raw file type. And of course, you can also save the ".CR2_original" files if you so want, so you can use them when Apple decides to support the S90 in the future, although I do not see a reason for that. If and when Apple announces that they support the S90, all you have to do is to skip my procedure and import the S90 files directly into Aperture.

I hope this trick helps other S90 and Aperture users, until Apple gets its act together and releases a new Raw Camera Compatibility package.

Download ExifTool and read (almost) all you ever wanted to know about raw files in this site:

http://www.sno.phy.queensu.ca/~phil/exiftool/

P.S. 1: If you want to enter a copyright message with your name in your CR2 files, you can change the command shown above to something like this:

exiftool -canonmodelid='PowerShot G11' -ownername='John Caradimas ©' *.CR2

Both the CanonModelID and the Copyright text will be entered in one go.

P.S.2: I am sure that ExifTool includes a parameter which will allow you to automatically move the converted CR2 files to their destination folder, inside your Master files folders structure. However, I find it easier to do that using the Finder, so I didn't bother researching this any further.

P.S.3: Since the CR2 files are now directly imported in Aperture, you can use any Aperture plug-in to edit them, for example to remove the barrel distortion which is prominent and the wide focal lengths of the S90 lens. I tried a couple of these plug-ins and they all work as expected.

P.S.4: For those who do not frequent this site and want to contact me, my addy is john at m1911.org.

__________________
John Caradimas SV1CEC
The M1911 Pistols Organization
http://www.m1911.org

A comment I received about this procedure implied (or I thought so) that my solution to the S90 support by Aperture, introduced distortion. Here are two pictures which are derived from the same CR2 file, one processed by Adobe DNG converter and the other one by the method described above. The difference in exposure is the only difference I can see between the two, barrel distortion is exactly the same.



For non-members: http://img.photobucket.com/albums/v...es/IMG_0272.jpg



For non-members: http://img.photobucket.com/albums/v...s/IMG_02721.jpg

Both pictures were imported in Aperture and exported to fit in an 800x800 pixel box, without any other adjustment. I can't see any difference in distortion between the two.

And here is the PTLens-treated output.



For non-members: http://img.photobucket.com/albums/v...s/IMG_02722.jpg

__________________
John Caradimas SV1CEC
The M1911 Pistols Organization
http://www.m1911.org

How interesting!!

I spend half a day to figure out the above and today Apple announced Aperture 3, which includes support for S90 raw files!!!

My contribution to Aperture users is now useless.

__________________
John Caradimas SV1CEC
The M1911 Pistols Organization
http://www.m1911.org

True. But a tour de force in hacking, nonetheless.

__________________
Hawkmoon
On a good day, can hit the broad side of a barn ... from the inside

Well, thanks for the effort to cheer me up. All I need to do now, is wait for the new Aperture version. Frank has already ordered it for me, thanks Frank!

At least I can still use my discovery to add my copyright info in the Canon files, before I import them in Aperture. Nikon allows you to enter such a text in every file, by a selection in their menus. This Canon doesn't have such an option, so I can use exiftool for that.

__________________
John Caradimas SV1CEC
The M1911 Pistols Organization
http://www.m1911.org

That was good work you did. I use Olympus, Nikon, and Canon in the digital world now, but convert images between MS, Apple, and a bunch of Unix platforms and you know all the various image formats.

__________________
NRA Life Member