Hidden RAW lens corrections in Lightroom & Photoshop
There are photographers who think that RAW files that they open in Lightroom or Photoshop are not yet edited. They are RAW files, right? Then you are mistaken.
An unedited RAW shot looks terrible. In an unedited RAW picture, the contrast and the sharpness are very low, the colors are not yet calibrated, and you see—with most camera brands—individual red, green and blue pixels. A RAW file is linear (the signal from twice as much light is twice as high), while the RAW files that we view on a screen are logarithmic (ten times as much light gives a signal that is twice as high). A RAW file from a camera with an anti-aliasing filter in front of the sensor gets extra sharpening.
In short: even if you set all the selection wheels for contrast, saturation, sharpening and noise suppression to 0, a lot of editing has taken place in Photoshop or Lightroom before you see the picture on the screen.
In the picture above, you do not see that the two areas at the bottom are grey and the top two areas are colored. You only see that after substantial editing is done in the RAW conversion (and the photographer has yet to do his or her editing). Even if you zoom in with Photoshop or Lightroom to 11 times the real size, a converted RAW shot does not look this pixelated.
The conversion of RAW in Photoshop and Lightroom is a complex process in which multiple modifications are made before you see the image on the screen. These differ by brand and camera type. We therefore do camera testing with jpg files from the camera ("WYSIWYG""), which you can consider as a worst-case approach for RAW files that you edit yourself. We convert the RAW files—where possible—in a different way. For each individual scale (RAW or jpg), the best camera or lens gets the highest score, and the poorest-performing camera or lens gets the lowest score.
There are sometimes great differences between RAW and jpg scores. The Tokina 14-20 mm f/2 at f/2 has little trouble from vignetting: only 1/2 stop, as it appears from our measurements on RAW files to which no lens corrections are applied. See for example “Vignetting: RAW vs jpg.” The jpg file that is stored in the camera simultaneously with the RAW file in this case shows 1 stop more vignetting at the same aperture. Some cameras automatically apply lens corrections, with which you can correct the distortion, chromatic aberration, and vignetting in the jpg files. In such cases, the distortion in a RAW file can sometimes be a couple percent, while there is no visible distortion in the jpg file that is simultaneously stored in the camera.
Although the measured values for a camera or lens review for RAW and jpg can be totally different, you see that the scores for RAW and jpg in the conclusion often match. One of the reasons for this is that we convert the measured values into a relative score: the best camera or lens gets a 9 and the poorest camera or lens, a 6. And a lens with a high score for sharpness in an unedited RAW file nearly always also has a high score for sharpness in a jpg file.
Hidden automatic lens corrections of RAW files
In Lightroom and Photoshop, you can choose for a number of brands (Sigma, Canon, Nikon, Tokina) whether you want to apply lens corrections to a RAW file. With other brands (Panasonic, Olympus, Samsung), you do not have that choice. With these brands, hidden automatic corrections are already applied before you see the pictures on the screen. The comparison of the distortion for two lenses with the same focal length, where 1 of the 2 has already undergone a hidden correction, is unfair. This is the reason why we do not use RAW files converted in Lightroom or Photoshop for any reviews.
How do you know whether a hidden lens correction has taken place in Lightroom of Photoshop? At the bottom of the Lens Corrections tab—if a hidden automatic lens correction has taken place in Lightroom or Photoshop—a notice: “Built-in lens profile applied.” If you click on the “i” symbol next to this note, then additional information appears.