My daughter's Fuji Instax laughs at all this talk of post-processing... "You push button. I give picture. All is good."
And there's a philosophical aspect of this... if I pick the square format on my K1 before I shoot, that's pre-processing... if I crop square afterwards it's post-processing... which is better? Which is more "pure"?
If I go and get the Rollei instead and shoot the image square on film, is that somehow superior? I might argue it is only because the Rollei needs some exercise... not for any other reason...
Don't agonize over it.
I am chronically inept at post-processing, and outside of whatever I have set at the moment for my JPEG settings, I typically limit most of my active post-processing to crops and simple, global changes to lighting and color. I generally use Photos on a Mac for that.
If I want to get fancy (focus stacking is so cool...), I'll use Affinity Photo because it was inexpensive, is plenty powerful for my modest needs, and because it has good video tutorials.
I tried the GIMP a million years ago, when I had a LINUX box and generally all software was horrible, so I'm a bad person to ask...
I spent a lot of time in a University darkroom years ago, prepping black and white images for publication, dodging and burning with paper clips taped bits of manilla folder. I like the new way far more.
As inept as I am compared to people who do this regularly, I can make small, simple tweaks to images that can improve them dramatically.
Even something as simple as a "heal" tool is post-processing magic... even if I use it on less than 5% of my photos.
A feature I also love about Pentax cameras is the ability to shoot JPEG most of the time but to simply chuck off a Raw whenever there is a particularly challenging lighting scenario or photo I think might be extra-good. There's no benefit up front. That's all for the post-processing. Maybe it gives me a better result, maybe not, but I like that it's there.
This was a shot with my wife's Minolta rangefinder. I changed the lighting and color a bit 'in post'. Took me a couple of seconds, but it improved the lab scan quite a bit and gave me back what I remembered the scene looking like. Post-processed? sure. Any "less than" the original scan? Nope.
-Eric