Data in Raw versus TIFF


Today’s Question: I’m wondering about the amount of data in an original RAW file vs that RAW file saved as a TIFF. I shoot Canon and all three of my current cameras have dust deletion as a menu option. It works really great but the problem is, it only works by using the Canon Digital Photo Professional (DPP) software. Once the dust deletion is applied the only options to save the file are JPEG and TIFF. My 1Dx Mark II is notorious for generating dust on the sensor. Even though the dust deletion adds an extra workflow step, it still saves time over removing hundreds of spots in Lightroom [Classic]. Any feel for what I may be losing by doing this spot removal in DPP and then continuing with “normal” processing in Lightroom?

Tim’s Quick Answer: I think it is perfectly reasonable to use Digital Photo Professional (DPP) for automatic dust removal, but I would also recommend applying at least basic overall tonal adjustments in DPP to help ensure the minimal amount of processing is required for the resulting TIFF image.

More Detail: The automatic dust removal feature available in certain models of Canon camera is indeed very impressive. You first need to capture a “Dust Delete Data” shot in the camera. While this process involves capturing a photo of a blank wall or sheet of paper, an actual photo isn’t captured. Rather, dust data is recorded by the camera, which is then appended to all raw (or JPEG) captures taken from that point forward.

The dust data is included in metadata, but requires the Canon Digital Photo Professional (DPP) software to process. So, you would need to use DPP to process the photos with the automatic dust removal feature. I also recommend applying basic tonal adjustments to get the overall image as close to final at this point, so less processing will be required later.

Save the final image from DPP as a TIFF image, and then import that TIFF into your Lightroom catalog. I would, for example, import the TIFF image into the same folder as the original raw capture you processed in DPP.

The point is that I would not be worried about significant loss of quality or detail in the image with this workflow. The TIFF image will be of very good image quality, with the benefit of dust spots having been removed automatically. You could then finalize the image in Lightroom Classic with any fine-tuning adjustments that are needed.

The TIFF from DPP will still be in the 16-bit per channel mode, so the file will still work very well if additional processing is necessary. You are losing a slight amount of flexibility in terms of processing the final image, but this is not something I would worry about in this context.