I read somewhere (I think within these sacred halls) that whenever we clamp a capo on our banjo it causes a slight change in tuning which must be taken into account when playing in a jam. My question is this: If this is in fact the case, and I am sure is it because we have capos on the market that claim to work without changing tuning, why do we not experience the same thing when we fret any individual string. Assuming that it is true, what makes one, but not the other, acceptable? While writing this out I think I may have answered my own question.
Could it be that the slight change in tuning is acceptable once but not twice. In other words, If a capo is added it slightly "sharpens" the tuning (perhaps not noticeable to the average ear): However, when we then fret the strings we sharpen the tuning again to, perhaps , an unacceptable level.
Set me straight if I am wrong.