Adobe Camera RAW (ACR) 4.1
Imaging - Imaging

Introduction

As of the time of this review Adobe Camera RAW 4.1 is the current RAW image converter of Photoshop CS3/Bridge CS3. The plug-in is not compatible to older Photoshop versions - a typical although unfortunate product strategy by Adobe. The principal usage concept remains the same like in older ACR version although Adobe beefed up the feature list and they also changed the demosaicing and sharpening algorithm (compared to v4.0 and older versions).

Here's a how the development user interface looks like ... (click on the image for an enlargement):

Workflow Concept

As a file import plug-in ACR is based on the underlying Photoshop infrastructure so it doesn't come with an own file handling. If you want to process a number of RAW files you have to drag'n drop those files into the Photoshop application which will then hand them over to ACR. Alternatively ACR can also be used within Adobe Bridge CS3 which features image organization functionalities like image rating, filtering, etc. pp. As you can see in the sample image above ACR displays thumbnails of your RAW files to the left side. The images can be rated within ACR but not filtered according to the rating. The currently active RAW file is displayed in the center whereas all (tab-grouped) RAW-processing controls are located to the right side. Due to the vast number of tuning option things are a bit cramped and you've to get used to the tab selectors functions (via tiny icons). You can apply changes to the RAW files in any order - ACR will store those in small .xmp files (one per RAW file) or a dedicated database. Once you're done you can either choose to open the selected results in Photoshop (usually not a good idea regarding the memory size of today's RAW files) or export them to storage. The process also works concurrently if your computer has the sufficient processing power - you can work on a set of new RAW files whereas ACR is exporting finished files in the background. If you want to improve your work you can also do so in another session based on your latest changes (stored in the .xmp files or the DB). Preferred settings can also be saved in "presets" for future re-use.

Processing Controls

CONTROL IMPLEMENTED
Basic ExposureYes
Auto ExposureYes
Highlight/ShadowYes
Tone CurveYes
Lateral Chromatic Aberration (CA)Yes
Purple Fringing (PF)Yes (doesn't work well)
VignettingYes
Auto Lens Flaw CorrectionNo
Distortions / Perspective No / No - available via the "Lens Correction" filter within Photoshop CS3
Rotate / CropYes / Yes
Noise ReductionYes
SharpeningYes
White BalancingYes
Color SaturationYes (per base color)
Color VibranceYes
Hot Pixel Detection/MaskingYes
Photo OrganizationNo - available via Adobe Bridge CS3
Import Formatsmost RAWs
Export FormatsJPEG, TIFF, DNG, PSD

Conversion Results

As mentioned Adobe changed both the demosaicing and sharpening algorithms in ACR v4.1. By default the results are somewhat softer although a bit less noisy compared to pre-4.1 versions. If you prefer more snappy results you can achieve an "old style" sharpness by tuning the sharpening options. Besides the common unsharp masking ACR 4.1 has now a "detail" slider - probably a technologies that made it from RawShooter (taken over by Adobe in 2006) into ACR. It isn't quite as aggressive as the old RawShooter variant but it does make a difference (without obvious sharpening halos) - it sharpen structures rather than edges. Another new feature is "clarity" - it seems to be a some sort of "macro sharpening" similar to unsharp masking with a very coarse sharpening radius. This works very well if you want to increase a faded edge contrast like a distant horizon vs the sky. The build-in luminance noise reduction requires a rather aggressive approach at cost of some softness so it should used with care - the chroma (color) noise reduction is very efficient though. The processing speed of the noise reduction is very high. Lateral CAs can be removed perfectly (unless you've an out-of-spec lens of course), same goes for vignetting. It is an all-manual process though. ACR 4.1 offers a new anti-purple fringing option but, frankly, it doesn't seem to do the job. There's still no way to correct distortions which is unfortunate because you have to rely on secondary applications if these flaws matter to you. Compared to pre-v4 version there're now new controls for color vibrance and especially highlight/shadow handling. Apart from exposure related functions you can also influence color saturation and hue here - Adobe refers to this as "Split Toning". The quality of the (optional) auto-correction has also been improved a bit without being perfect (naturally) - most of the time you will probably still prefer manual fine tuning.

Conclusion

Adobe Camera RAW v4.1 is a quite significant evolutionary step up from v3.6. It takes advantage of the same basic concepts and adds new controls for (structural) details, clarity (macro sharpening), a simplified handling for highlight/shadow control, color vibrance and a more detailed approach to color saturation and hue. ACR is "only" a plug-in but it is reasonably well integrated into Adobe Bridge CS3 (which takes care of the image organization aspects) and Photoshop CS3 (for further corrections). If you prefer a more harmonic combination you can get the same ACR feature set in Lightroom v1.1. All-in-all it is the tool to beat but it is not perfect - there're still no correction controls for distortions/perspective and the anti-purple-fringing isn't overly efficient.

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