Usually, I recommend using straight-from-camera RAW files to merge into a single HDR image, but when I’m working with Sigma X3F RAW files, I change my workflow a little bit to take advantage of the Foveon chip’s Bayer-less design to smoothly upsample the source images in Sigma Photo Pro 4.2 for big, top-quality source TIFFs to bring into my HDR programs. First, obviously, I pull all the photos from my camera card into a single folder, and then I open that folder using the folder navigation window in Sigma Photo Pro 4.2. I make sure all photos are highlighted and click the “Save Images As..” button, which launches the big dialogue box. I click the “New Folder” button and name a nested subfolder “Double Size” as the destination. I want these images processed straight from the camera’s capture decisions, so I tick “X3F” in the Adjustment Mode field and select “Double Size” as the Output Image Size, keep the color as sRGB, and select 16-bit TIFF as the file type, which creates big, beautiful 5280 x 3520 pixel source photos that will bring a wealth of information into our merged HDR image. I click “Save” and let my computer chug away as Sigma Photo Pro churns out all the big 16-bit files.