I have L-lenses. So I will be doing color adjustments on the computer, if I understood waldo correctly.

Sorry if I came across as directing that at you, I just wanted to complete the list of the 4 different ways to that saturation is affected for a given scene, the glass, in-camera settings, RAW settings, and general photo editing software. (your list was missing a very important point IMO)

If you shoot in .jpeg, in-camera settings are vital to the final product.

If you shoot in RAW, the data captured in the RAW file itself is what you get from the glass, camera settings are recorded as metadata and passed into the RAW editor (Canon's RAW program is a mirror of the camera settings). 

The RAW programs color adjustments are made before the image is assembled into a standard RGB image (or if none are done it just uses the in camera settings, if there were any), when chromanance and luminance are still separate and discrete.  If any noise reduction is used in the RAW editor, this is applied as the image is assembled, generally superior to applying noise reduction after the image is assembled (especially for chromanance noise) Hence you can boost the saturation and filter the noise resulting from the boost before it is combined with the luminosity. 

The RAW editor takes the place of the portion of the camera's processor that assembles the image, adjusting settings prior to image assembly yields superior results in almost all cases, this is why in camera adjustments are vital for .jpeg shooters, it is done prior to the initial noise reduction (noise reduction is almost always applied to a .jepg in-camera).

Complete photo editing software though has it's advantages as well.  RAW programs and camera settings lack features.  You can fine tune individual color channels (and derivatives) much moreso in editing software.  And with the full PS you can convert to LAB mode which mimics a RAW file in structure (separating Lum and Chrom), but have the full features of the software at your disposal, including adjusting the tone curve of the applied saturation (adjusting the curve for half of a Chr channel), point or area saturation (as opposed to global changes, using masked layers), and individual saturation channel control, features lacking in a RAW editor or camera.

For every image the best means of boosting color are different, it really depends on the initial capture, the desired end product, and the means that you have.  If a global single slider is the best way to go, nothing beats the RAW editor (especially since exposure can be tuned with the saturation).  If fine tuning would yield superior results, even if a little noisier (and the extra time spent is justified in the results, not always the case for little minor differences), image editing software is the way to go.  If editing time is at a premium or you shoot in .jpeg, in camera is the way to go.