I'm a little twitchy about editing questions after answers start showing up, since I believe that changes to the question can (unintentionally) orphan answers to that original question. In a recent example, the title of the question changed in a way that, in my opinion, changed the focus of the question, making the question fit one particular answer exceptionally well.
This question admittedly seemed a little subjective from the onset, and it suffers in form. There are, in fact, two questions and a small background narrative in the question as originally posted. Neither of those questions, however, have a lick to do with whether saturation should be important. The first question is whether Nikons produce saturation than Canons, and the second (already presuming an answer to the first) is whether that difference can be negated somehow. By changing the title of the question, the meaning of the original question has been changed, and as it stands, only one answer addresses the "does it matter" part at all!
For the record, I agree that "does it matter" really is a far more important question than "do differences exist" (as do most of the commenters). I also believe that jrista's answer is a comprehensive and thorough answer to the original question. I do, however, disapprove of changing an existing question to more closely align with an existing answer, most specifically when that answer belongs to the editor.
Personally, I'd love to see questions locked from editing once answers start coming in. Barring that, however, I believe that if you're going to edit a question, great care is needed if you also answer, either prior to the edit or following the edit. I feel that when you change the meaning of a question to better suit your answer, it's a particularly insidious (and very probably subconscious) form of answering your own question (which is accepted and even encouraged on SO). However, while there are measures carefully put in place to guard against gaming the system with self-answers, no such measures exist (that I'm aware of) to guard against orphaning answers by changing the meaning of the question.
This seems like another example where P-SE is susceptible to a problem that's just not seen in the original SO site. Changing the title of a highly objective question, for instance, isn't likely to change its meaning, and an edit to a technical question is going to stick out like a sore thumb (hey, dummy -- your example doesn't compile anymore), but when you start with a question that's borderline-subjective in the first place, subtle edits matter.
In case you're wondering, I'm posting this here (rather than commenting on the original question) because I'm really more interested in the general case of question metamorphosis and its impact on existing answers than I am in that specific question. I don't think there's an automated solution here; rather, this is an etiquette question.