I'm not a dissenter, but I'm curious. If you shoot in raw... the images all look blah until you change the contrast, remove the vignetting... and fix the white balance. I also add a touch of saturation... shoo if a shot requires that much adjustment from the original raw.. how do y'all really know if it was the lens that didn't have good color, contrast, etc?
Good questions, and white balance affects the entire image so it should be set first. Cool lenses, like many of the older Sigmas have a blue or yellow tint to them that remains even when you adjust white balance. Canon lenses are a bit warmer than neutral, which most of us are used to and like if we shoot Canon.
When you open the raw files, (in my case in PS or DxO), I can tell right away if I need to add saturation/vibrancy. I don't think I've ever added any saturation to my 180 Macro shots, vs. adding 30+ to my old 24-70 [MkI] or lenses that I use with the 2x extender. For contrast, my 50 1.4 looked faded and washed out at f/1.4, but had lots of contrast at f/2. In comparison, the 50 1.2 has as much contrast at f/1.2 as it does at f/4.
Lesser lenses require a boost in contrast, whereas lenses with amazing contrast (like the 300 2.8 IS II) require little to no boost. For a shot in soft light, if you add more than about +5 to +15 contrast, the image gets dark and mushy, whereas the old 24-70 would need around +30 to get the same look.
Adding color saturation and contrast seems simple, but in photos with wide dynamic range (lots of shadows) or highly saturated colors (like flowers), boosting them too much not only looks unnatural, but it "crushes" the blacks or saturated colors and you can lose a lot of detail.
As for the other artifacts, like CA and vignetting, if DxO can't get rid of the CA (like on my Sigma 12-24 II) that says something, and even DxO can't do much about Longitudinal CA (LoCA), which usually shows up in high contrast areas of lenses f/1.4 and faster. It's ugly green and purple lines and can be 4+ pixels wide so it's really noticeable. I usually desaturate the LoCA in PS as that's about all you can do.
Vignetting on lenses like the 50L and 24L II is horrible and with the 24L II, it is an issue when shooting landscapes and architecture in low light. You can expose to the right (as I do) but when you open the shadows in post, the corners have a lot more noise because they've been pushed several stops (via the vignette removal) vs. the center that has been pushed a lot less.
Maybe I'm a little too @n@l about these things, but when you start making big prints, you really start noticing this stuff. There's nothing worse than a client who wants a big print of a photo that looks great online but has lots of "technical" issues when you go to print it.
I'm gonna invest in FoCal too...especially when I get the 50L and the 85L. I'm of the thought that those lenses with such a narrow DOF, definitely need the micro adjustments to get the most out of them.
Yes, that is a HUGE help with the f/1.4 and faster lenses and the optimal adjustments after calibration have less CA, which is a nice bonus on top of the improved sharpness.