DxO PureRAW 4 review

Pros

+ The best high-ISO denoising process on the market
+ Excellent automatic lens corrections, including for edge softness
+ Super-easy to use and can be left running in the background
+ Much more control over processing options and strengths than previously
+New preview window with automatic updates

Cons

– Seems quite expensive for such a specialized tool
– Fixes moderate edge softness but really bad softness will stay soft
– DeepPRIME XD2 does not support X-Trans files

What is DxO PureRAW 4?

DxO PureRAW 4 is a very interesting RAW processing tool built around the powerful lens correction and denoising technologies DxO has been pioneering for years, which also feature in its flagship product DxO PhotoLab.

Essentially, PureRAW 4 is like a RAW converter that takes your original RAW files, corrects lens aberrations and corner softness, cleans up the noise and outputs either a Linear DNG file, which is like a ‘part processed’ RAW, or a ready-to-share JPEG or TIFF image.

These Linear DNG files are very clever. They look and work just like a regular RAW file in other software, but are pre-processed with DxO’s unique lens corrections and AI-powered denoising. You still get all the flexibility of RAW files, like extended dynamic range, white balance adjustments and extended color data, but with DxO’s excellent lens corrections and noise reduction pre-applied. DxO claims its corrections are better than all the rest, and not without reason. The only issue with Linear DNGs is that they are 2-4 times the size of regular RAW files, so keep that in mind.

Or you can simply use PureRAW 4 to generate JPEG or TIFF images from your RAW files. PureRAW 4 can also apply DxO’s Smart Lighting adjustments to recover extra shadow and highlight detail during processing.

There are perhaps two key ways to use PureRAW 4. You can use it as a standalone application for batch processing  folders full of images, and you can use it as a Lightroom Classic plug-in to ‘round-trip’ RAW files and achieve a far higher level of quality than you can in Lightroom itself.

In addition, should you want to work this way, you can process images directly from within your computer’s file browser or, in PureRAW 4 there’s a widget that can automatically detect memory cards or newly-added drives and offer the option to convert images directly.

DxO’s lens corrections are based on specific camera-lens combinations tested in DxO’s own labs. DxO has now generated no fewer than 90,000 correction profiles, with more being added all the time. It’s pretty unlikely that your own camera-lens combination is not supported, but you can find out easily enough by signing up to DxO’s free 14-day PureRAW 4 trial.

If you do decide to buy, DxO PureRAW 4 costs $119/£109 for new users or $79/£69 for registered users upgrading from a previous version.

What’s new in DxO PureRAW 4?

Talking of upgrading, is it worth paying the upgrade fee if you’re using a previous version of PureRAW. To help you decide, here’s a list of new features in DxO PureRAW 4.

First, it comes with DeepPRIME XD2, a revised version of DxO’s denoising technology which provides enhanced fine detail. Be aware, though, that this does not yet support Fujifilm X-Trans files – these will revert to the original DeepPRIME XD process, though the differences are subtle and you may not even notice.

DxO does say that DeepPRIME XD2 brings cleaner images with more accurate colors, better detail extraction with no halos, artifacts or fringing, plus smooth focus transitions and bokeh blur.

PureRAW 4 now has slides for fine-tuning the processed results, an overhauled processing dialog box that’s both easier to understand and now offers the option to use or not use DxO’s Smart Lighting when exporting TIFFs or JPEGs.

You now get real-time correction previews too, though these can take a few moments to render, depending on the speed of your computer, and you can choose to switch them off. There’s also a new Comparison mode to check before-and-after versions, plus advanced batch renaming using tokens and custom text, plus a new widget for automatically detecting images on memory cards or external drives when added.

DxO PureRAW 4 design and usability

DxO PureRAW 4 really is very easy to use. If you launch it as a standalone program you can simply drag and drop a folder of RAW files on to its window and it will display them as thumbnails in a processing queue in its ‘lightbox’.

You can opt to preview and process individual images to check the effect of the different processing tools and strengths, or process a whole folder full of images according to your chosen settings. These are easy to set up and will be displayed immediately prior to processing – and if you need to change any of them you can click an Edit button to modify the settings.

Processing is not instantaneous. The DeepPRIME process is pretty hardware intensive, and while it’s a lot quicker than it used to be (and computers are a lot quicker too), a large batch of images can still take some time. It’s best to leave PureRAW running while you get on with other jobs.

The other key way to use PureRAW 4 is from within Lightroom, and this is rather clever. When you export a RAW file to PureRAW 4 in Lightroom, you’re prompted to check the processing settings and then PureRAW 4 goes off and does its stuff, returning a processed DNG file to Lightroom in a few seconds (on a fast computer).

The particularly clever part is that this new DNG file will adopt any processing steps previously applied to the original RAW file automatically, so this is not something you have to do right at the start of the editing process – though I have found that the different geometrical corrections applied by PureRAW can sometimes interfere with any AI masks you’ve applied in Lightroom. Also, while the color and tone matching are close, there can sometimes be visible differences between your original RAW file and PureRAW’s Linear DNG version. 

One key thing worth pointing out here is that Lightroom does of course have an Enhance option which also applies AI noise reduction, and while I don’t think it renders fine detail quite as well as DxO’s DeepPRIME process, it may be close enough for many users not to bother with the DxO process.

DxO PureRAW 4 results

DxO PureRAW 4’s results vary from the good to the genuinely transformative. I’ve tried it on combinations of full frame sensors and pro lenses and found the improvements to be pretty modest, at least at low ISOs. You do get an improvement in sharpness, but perhaps no more than you could achieve manually in Lightroom. However, at higher ISOs, say ISO 1600 and beyond, the advantages of DxO’s DeepPRIME processing become obvious. The differences aren’t small, they’re game-changing.

At the other extreme, if you have an older camera and less expensive ‘consumer’ lenses, PureRAW 4 can deliver results which are, at times, hard to believe. I have a Canon EOS 50D from 2008 with a pretty dated 15MP sensor, matched up with a 15-85mm zoom, which is itself hardly a stellar performer. But with PureRAW 4, this camera’s images are transformed from mush into decently detailed photographs that would still be perfectly usable today. And while the EF-S 15-85mm starts to turn to jelly near its longest focal lengths, PureRAW pulls back enough definition and detail to make even these perfectly usable.

In between these extremes, there’s a whole mass of mid-range cameras and lenses that are good, but could always be that little bit better, and PureRAW 4 can sprinkle a little magic over all of them. You don’t just get excellent lens corrections for distortion, chromatic aberration and vignetting, but correction for edge softness too, so that the image edges are sharpened up but the central areas are left alone.

There is another clever feature. One of PureRAW 4’s processing options is to respect the original crop area or deliver the ‘maximum rectangle’. Barrel distortion correction involves ‘pushing’ the edges and corners of the image outwards, and the ‘maximum rectangle’ option means you get to keep all these areas instead of having them cropped off. Very often, PureRAW 4 will show a wider angle view than the camera’s own JPEGs or RAW files.

PureRAW 4 does slip up occasionally. I use a Sigma 10-18mm f/2.8 with my Fujifilm X-T5, and while PureRAW does correct distortion, vignetting and corner softness well, it trips up on the chromatic aberration removal, actually making it worse not better at the edges of the frame. Remember, though, that this is with the original DeepPRIME XD process, since the newer and better DeepPRIME XD2 version does not yet support X-Trans RAW files – so perhaps in this instance we should give PureRAW 4 the benefit of the doubt.

DxO PureRAW 4 verdict

The question is not whether DxO PureRAW 4 is good at what it does, because it is very good indeed. Perhaps the real question is how much you need it. It does offer a massive improvement in noise control over Lightroom’s own RAW processing, but then Lightroom does have its own Enhance feature, which can get you a long way towards DxO’s results – though it still doesn’t quite measure up, in my opinion.

If you’re a Capture One user, as I am, you will again see an improvement in noise control, though Capture One is better than Lightroom at both noise control and detail rendering, so PureRAW 4’s DNG files do not always offer a substantial advantage, and they do add to your workflow overhead. For Capture One users, perhaps PureRAW 4’s biggest advantage is that it has lens profiles for just about any low-end or mid-range consumer lens, while Capture One doesn’t always bother with kit lenses or cheaper third-party zooms.

For users of any other software, PureRAW 4 is a much stronger proposition. Almost any photo editor these days can process RAW files, but the results are often pretty disappointing. All RAW processors are not the same!

PureRAW 4 even has appeal if you don’t intend doing a lot of editing and simply want top-quality JPEGs. Here, you can shoot RAW files with the camera and then use PureRAW 4 to output super-sharp, super-clean JPEGs and, if you choose the Smart Lighting option, with shadow and highlight recovery too.

So that’s my verdict. First, figure out if you need PureRAW 4, and how much. If you do decide you need it, I really don’t think you’ll be disappointed. It does its best work with low-end or mid-range camera gear, where it’s so effective it can genuinely make you reappraise what your camera can do. Sometimes you don’t need to upgrade your camera gear, you just need to upgrade your software!