How to Tolerate DxO by Hacking MakerNotes and EXIF Tags

DxO Optics Pro was a purchase I immediately regretted making, once I realized that it intentionally restricts you from selecting what lens optics you’d like to adjust your photo with. It would take all of five minutes of programming to let the user decide, but for whatever stupid reason, if you’re using a different lens than the one they support OR if you are looking to adjust a photo that you’ve already adjusted in a different program, DxO becomes relatively useless.

I’ve figured out a couple easy ways to hack the tags in a raw image file to “fake” a different kind of lens. This worked for me. I make no guarantees it will work for you. In my case, I have a Canon 8-15mm Fisheye, which isn’t supported by DxO. The fixed 15mm Fisheye is, however, and since I only ever shoot at 15mm, I’d like to use the fixed module to correct. As it turns out, the module does a decent job once you fake DxO into thinking you actually used that lens.

This isn’t as easy as it would appear. You have two choices. You can clone the tags from a raw file that perfectly matches the lens, camera, and resolution of your own photos, but finding an exact match to this is difficult. In my case, I couldn’t find a fixed 15mm Fisheye anywhere, because it’s discontinued. Nobody online posted any sample pics using a 5D III, and the resolution was lower (forcing me to shrink my image if i wanted to fake it this way). If you’re lucky enough, however, to find an exact match to serve as a donor raw, you can simply do:

exiftool -all= -tagsfromfile donor.cr2 -exif:all mypic.cr2

This also comes in handy if you’re editing photos that you’ve already edited, whose MakerNotes have been dropped by Photoshop or whatever other program you used. You can simply use an unedited image straight from your camera and copy the tags back into the edited photo; it will load into DxO with no problems, and recognize the correct module.

As for me, I needed to do something a little more drastic. If you run exiftool with the -args argument, it will print out the list of exiftool commands to actually set the tags for a particular image. Not all of these can be simply copied and pasted, but a lot of the time you can tweak them to read what you want. Using this, I was able to figure out how to take one of my CR2 images, taken with an 8-15mm Fisheye, and rewrite the tags to simulate the exact ones you’d expect for a fixed 15mm. In fact, I wrote it into a little bash function that you can stick in your .profile on a mac.

function fisheye_raw {
exiftool -LensModel=”EF15mm f/2.8 Fisheye” “$1″
exiftool -LensType=”Canon EF 15mm f/2.8 Fisheye” “$1”
exiftool -LensInfo= “$1”
exiftool -LensSerialNumber= “$1″
exiftool -FocalLength=”15.0 mm” -MinFocalLength=”15 mm” “$1″
exiftool -MaxFocalLength=”15 mm” “$1”

Now to fake out DxO, all I have to do is run:

fisheye_raw myimage.cr2

Then load it into DxO. The software will assume you’re using the fixed fisheye, and give you access to all of its optics correction modules. It’s not perfect, but they do work relatively well with the 8-15mm Fisheye @ 15mm. Of course, you could do this to fake any lens if you have the right information.

Once you’ve built a single working CR2, however, I found it easier to just clone the tags (unless the remaining exif data is particularly important to you). The function works on raw, but doesn’t on jpg, so you’d need to create a donor raw file from this first, then clone the tags over from your raw to your jpg.

That’s it, really. I am so frustrated at the $300 I blew on DxO that I decided to figure out how to hack around their stupid module restrictions just because it is the decision of the photographer – and NOT the software manufacturer – to decide how I want to correct my image with their software. How arrogant that these people would presume to force the photographer to edit the photo how they see fit?

One other thing that really ticks me off about DxO is that you can’t move it to another machine because the license is tied to your three MAC addresses (en0, en1, and en2 if it exists). In order to get DxO to run on a different machine, you have to manually set the MAC address to match that of the original machine you activated with; e.g. “sudo ifconfig en0 ether xx:xx:xx:xx:xx:xx” and so on for all three hardware addresses. Just another insulting “feature” added by DxO to make life impossible for their users.