Some people erroneously assume that when you click the shutter the camera records *exactly* what you see with your eyes. Some then conclude that any post-processing you do, other than cropping and leveling, is turning the photo into something it wasn’t’. In other words, you created a somewhat false image.
What a camera “sees” still has to be interpreted and processed. The final image stored to the memory card has already be “post-processed” – just inside the camera. Some of the in-camera, post-processing is influenced by settings you have control over but some isn’t. Camera manufacturers have their well-guarded algorithms for doing this processing. Objective testing can show subtle differences in color and sharpness between different cameras while shooting the same image, with the same settings and lighting. Our own human vision is similar. Due to the curvature of the lenses in our eyes, images projected on our retina are upside down. Our brain inverts them so what we “see” is right side up. Our vision system is really more like recording video as our eyes keep adjusting to the light as we look over a scene. A still photo, though, is just one moment in time. Without some post-processing the images captured by cameras won’t match what our eyes saw.
There is also something called “RAW mode” available in high-end cameras. When a digital camera takes a picture, the sensor records the characteristics of the light hitting it. An analog to digital conversion is done and a “raw” image is produced. The camera’s sensor then does a little post-processing on that raw image then converts it into a jpeg and writes that jpeg to the memory card. Jpeg is a file format for storing photos on computers. To convert that raw image into a jpeg some compression has to be done to keep the file from being too big. This results in some loss of data. The conversion algorithm tries to intelligently eliminate data but some information you might want is lost. The alternative is to configure the camera to write the “raw” image to the memory card (most also offer the ability to write both the raw and the jpeg to the memory card). Once the raw image is uploaded to the computer it can be edited as can the jpeg. The raw image, however, is uncompressed and contains more information than the jpeg does. This allows for better editing and the ability to correct for more problems. Things like white balance (the color of the light) can be far better adjusted in the raw image than in a jpeg. Editing in raw mode gives the photographer more control over the image. He or she gets to make critical decisions instead of leaving it up to the camera. Often times the raw image looks a little less polished than the jpeg if you set the camera to produce both. That is only because the camera started with the raw image and adjusted it to produce the jpeg. Until you do the same the raw image make not look as good. Shooting in raw mode takes up more space on the memory card and computer and takes more time since you have to post-process the file but can yield superior results.
Naturally there is a point in post-processing where the photographer has the option to make artistic changes. These are intentional departures from what the scene really looked like. It might involve lightening some dark areas, saturating colors for more pop, selectively sharpening or blurring areas, etc. In some cases you could be changing the scene but still producing one that could occur under different lighting conditions. In other cases you could produce an unnatural scene but maybe a dazzling, idealized one. There are no black and white rules about what changes to make. If the photos is going to be used in a travel guide or brochure about a location then you generally want it to be realistic. Same with photos of people or animals. For other uses, though, it’s perfectly fine to create an artistic rendering of the scene. As long as you don’t intentionally deceive someone into thinking an altered scene was 100% accurate. There may have been a distracting telephone pole you removed and a dull sky you livened up. Such changes are not major modifications to what that scene might look like. I’ve had people ask if some of my photos were “worked on” because they look a little too good to them. Often times I really didn’t do that much beyond improving the contrast. In the end, though, does it matter? If you really like it then who cares? We all admire artwork that was artificial or art inspired by real scenes but modified like what an impressionist painter might do. As they say, “Beauty is in the eye of the beholder.” Some photographers act like making *any* artificial changes to a scene is wrong. I say it depends on your use of the photo and whether or not accurate reproduction is required.
If every photographer just went with the exact image in the camera we would not see some of the amazing photos we have and there would be a lot less variety and less artistry. I say “viva la difference”!