Earlier this year [2004] Keith reviewed the DxO lens correction software and found that despite its powerful correction functions, it would be of limited use since he invariably uses his camera's raw format when taking pictures.

A new version of the program (DxO optics Pro 2 and the DxO RAW Engine) that does raw conversion as well as the lens correction is now here.

Keith has been looking at it both from a conversion quality point of view, as well as how he could include it in his day to day working.

Due to the large number of images this review is split into two parts, with results and conclusions in Part 2

Why would I want another raw converter?

I've discussed some of the reasons for using raw format in another article but it is mostly for the quality of the image produced.

Adobe have included the excellent 'Camera RAW' (ACR for short) in Photoshop CS. I use it a great deal, and once you understand the numerous options available in advanced mode it is very powerful. In particular you can use it with the file browser and scripting (see Dr. Browns Image Processor).

Whilst reviewing some of the several thousand images I've taken this year I've been noting those that although they might potentially make good prints, they just didn't live up to expectations when I started working on them.

The second reason for using raw format, is that you can always go back when new software becomes available...

Many of the examples in the article are from raw files that just didn't work as well as I wanted. In the course of my testing I discovered that even some of my minor complaints about the Canon 1Ds might not be all down to the camera.

In this review I'm looking at the DxO Raw Engine being used with DxO Optics Pro 2. All test images were shot on a Canon 1Ds. The software was run on a Dual 2.5GHz G5 Macintosh (3GB ram, OS X 10.3.6) The software also runs on PCs...

What does the software do?

At its simplest the software converts raw files to Tiffs and can additionally correct distortions in images. You can have 8 or 16 bit output and attach any ICC profile you might want to the images (defaults are sRGB and Adobe98)

I've discussed the distortion side of things in the previous review, so I'll just mention them briefly here

There are four areas of your image that the software currently addresses:

Geometric distortions - this includes barrel and pincushion distortion, along with more complex patterns.

Vignetting - Where the brightness of your image falls off towards the edges of the picture.

Blur or Lack of sharpness - This corrects some of the blurring introduced by your lens/camera combination. It does not extract detail where there was none, it just gets the best from what there is in the image.

Lateral Chromatic Aberrations. This is a where different colours focus at slightly different places on your image sensor, giving coloured fringes.

There is a lot of information on what is going on in the various parts of the software on the DxO site at http://www.dxo.com/en/photo/technology/default.php I'll not go into all the details here, but even something like vignetting is not as simple to fix as you might first think.

The software

Opening the program gives a basic file browser where you can see thumbnails of currently selected files. In the (annotated) example below are five files that I have dragged to the window to select them. The little tick marks next to the images mean that all necessary info is present to run the program.

File window showing files to be converted

To perform correction as well as raw conversion the program needs to know quite a bit of info about the original camera settings. My 1Ds for example does not save focussing distance in its EXIF data, so you have to enter it.

File is missing some info Settings for raw file conversion and correction

The little question mark indicates that I need to enter missing info for this image.

Note that you do not have to apply corrections and can just do the raw conversion.

Some of the many options that you can adjust for conversion and correction.

This example is for the car image above, where there is no focus distance info supplied by the Canon 1Ds

White balance can be set to a number of presets or fine tuned as desired.

Of course you can always use the camera's estimate.

Exposure compensation is available (+-4Ev) and the histogram is directly updated.

Distortion correction is adjustable from 0 to 100% (it is greyed out, since I have not yet entered a focusing distance)

Vignetting correction can also be varied from 0 to 100% and a second adjustment allows for it to be varied based upon image content (preserving highlights and preventing excessive shadow noise)

The output sharpening can be varied from soft to sharp, although examples in this review are all taken at the default setting.

The correction actions are the same type as shown in the earlier review, so I've not included them all again here. You do now have more control over the amount of correction applied and can preview the results.

The one example from the earlier tests I've included is the vent on the wall (1Ds, EF 16-35 2.8L at 16mm).

If you move your mouse over either image it will switch from the ACR to the DxO conversion (with correction)

The enlarged version (100%) is an unsharpened comparison between ACR and DxO -- at their default settings.

The Photoshop histograms of the two files are shown below.


ACR	DxO

The image below shows the effects of altering the sharpening setting from 0 to 2. Note that all the rest of the images in this review were converted using the default setting of 0. The default settings with ACR include some sharpening and colour noise reduction. Please consider this when comparing images.

As with all images in this review there is the basic problem of how to show subtle differences in images, on a web site, where I don't know how you are viewing them, and any hope of accurate colour management is but a dream. I'd very much suggest you try your own comparisons - please bear this in mind when you are looking at the images in Part 2. Note also that I've not sharpened or processed any of the sample images. If the images look a little dark, check our monitor set-up page for more info.

More examples of conversions and Keith's conclusions are in...

Part 2 of this review

Other Info on this site that may be of interest

DxO Optics Pro V3.5
A review of the latest update to the DxO software. It adds many new features to the RAW conversion software that Keith regularly uses for his landscape prints.

Using a tilt and shift lens
Keith has been experimenting with using the Canon TS-E 24mm 3.5L lens on his 1Ds. Lots of images showing some of the effects you can get and why in conjunction with Photoshop it makes a good choice for some interior and architectural work (even hand held).

Focus Magic
Image processing software to fix camera shake and focus blur.

The views in this article represent those of Keith Cooper. Keith is always happy to discuss matters raised in his articles. You can Email Us

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