Which programs open .tif files?

Converting CRW raw files (Canon G6 camera) to TIF files -- Canon Zoombrowser vs. IrfanView vs. Raw Therapee?

• When I shoot raw with my Canon G6 camera, I currently have three different applications that will convert the Canon .CRW raw image file to a .TIF file. Using the same Canon .CRW image... - Zoombrowser EX 6.3 yields 3072 x 2304 TIF file that is 20.818 Mb - IrfanView yields a 3072 x 2304 TIF file that is 20.755 Mb - Raw Therapee yields 3104 x 2320 TIF file that is 21.101 Mb From the comparisons that I have made thus far, the TIFs I get from Zoombrowser and IrfanView look pretty similar but still slightly different, while the TIFs that I get from Raw Therapee look a bit darker/less-exposed/more-saturated. 1) Why do such differences exist? 2) Shouldn't the Irfan and Raw Therapee software developers be using the same methodology and standards as Canon for the conversion process? 3) Or maybe they can and have improved on the conversion methodology used by Canon? 4) If the sole concern is the image-quality of the converted .TIF image file, which of these three conversion application would you recommend? 5) If the sole concern is the image-quality of the converted .TIF image file, would you recommend another conversion application, and if so what would that be? [I am aware of the fact that IrfanView does have a quick and easy-to-use batch processing feature, but my sole concern at this point is image-quality.] ~ thanks for your answers ~

• Answer:

  A raw file comes out as linear light space. If you were to look at the linear space image, it would look horrible! To mimic what your eyes perceive, the linearity of the light amplitude is skewed in the raw image. Also, the color space is what the sensor sees which isn't what you perceive. Programs which convert raw data files to a format where your perception of the image looks normal need to bend the light space and adjust the color space to a pleasing image. The algorithms used to do this vary between the software which is why you are seeing the differences. I would say that Canon's software should give the results closest to the jpeg thumbnail embedded in the raw image since Canon knows what algorithm the camera uses. Your file size differences are probably due to header information and the pixel dimensions in RT are due to how they handle the edges of the image. If you want a good raw editor, use Adobe Camera Raw (ACR). It is a wonderful program. ACR comes with Photoshop (expensive) and Photoshop Elements (under $100). If you want to see what the image really looks like from your camera sensor, use a command line program called dcraw. Use the -4 option. Purists doing HDR processing will use linear light space then adjust the final result so it looks normal to the viewer.