I think that’s definitely part of it, as well as the fact that the act of playing a guitar often forces it out of tune. At big concerts, I suspect that, when the guitarist swaps guitars, a crew member is then re-tuning the guitar that was just handed off.
As much as I need a capo, having a narrow vocal range, they’re hell on those of us with perfect pitch. Telling your fingers to play a Cxxx when your ear tells you to play an F#xxx is madness-inducing. It’s a trade-off, for sure.
I was going to post this earlier, but I had to figure out where to find it again. This is an interesting capo:
Well, you could do part of what that gorgeous young lady was doing in her video and clamp down on just some of your six strings.
Start in Open D. Capo five of your strings at the 2nd fret and you’re in Drop D; Capo all six at the 2nd fret and you’re in the equivalent of Open E. Standard tuning? That might be a bit tougher. 
G!
Did you need to learn your perfect pitch or is it natural?
You are different to me knowing mad best guitarists, I mostly just play in my basement as is my lifestyle but you don’t need the exact right guitar and sound for playing live, that’s quite exaggerated by gear companies. Sure there’s specific sounds from specific instruments and amps and effects and what not but a lot of it is marketing.
Some guitarists use digital wizardry to retune their guitars, is that still a thing I don’t know I will google it now and get back to you all.
Polyphonic pitch-shifting pedals are “a thing” in that they exist and you can use them in a performance. I imagine such a thing might be useful if you need to instantaneously change the tuning in the middle of a song, or mess around with large intervals (e.g., you could retune every string up or down an entire octave, and maybe mix that with your original signal), and other effects.
Thanks for getting back to us all I did google but still wasn’t sure. I just remember some guitarist saying he used a digital pickup, tuned EADGBE like a normal human and just retuned digitally to do open tunings and all sorts. This was 20 years ago too.
I played his guitar it was a strat with the extra pickup added afterwards, but it wasn’t plugged in, I was just making sure it was in tune normally.
Perhaps I’m misunderstanding, but a Drop D tuning is standard tuning with the lowest string dropped to D, not an Open E tuning with the lowest string dropped to D, which is what your first two sentences would effect.
If you tune to drop D and you put a capo on the guitar at the second fret it’s in Drop E.
Starting in concert tuning if you capo the 5 thinner strings at the second fret you end up in Drop E as well.
But when you play in drop E, psychologically, you are still playing in “Drop D”, with all relationships preserved.
Yes. Sorry – it’s a little hard to tell if you’re addressing me or another point made in the thread. All that is correct. But I’m confused by the post I replied to. If you start in Open D and capo five of the strings at the second fret, you’re not in Drop D, actually or psychologically. You’re in this tuning: D B E G# B E, some sort of E/D tuning. For Drop D, you would have to start in Standard D, not Open D tuning, and capo five strings at the second fret. Then you are, as you say, in Drop E or psychologically Drop D. You start from standard tuning, not open tuning.
Or is their another type of drop tuning that starts with open tuning that I’m not aware of? The whole point of Drop D is that the lowest and third lowest string are an octave apart. You get that in open tuning automatically.
The “open D” I just ignored. I think they were confused, although they can answer for that.
In talking about these things by post there can be a lot of terminology drift and errors. It happens to me. To me when I am in drop D, no matter what fret the capo is on I just think “Drop D” Speculating about the actual key is not productive for me, just confusing. (It only happens on threads.)
The decision to use a capo is having to do with pitch and tone, of an already tuned guitar, and about a song that is finished. The decision to play in an open tuning, D or G, or whatever, is more when the song is written, before you ever think about the key.
Yeah, that’s pretty normal and I account for that. Like I said, I’m not a guitarist, but when I’m capo’ed up, I still think of them as D, E, A, G, etc. chords, just with a capo at a certain fret. Or, more often, when I’m tuned to Eb, I still think in terms of E. Unless I’m playing keyboards (which is what I normally play). The band I used to play in was always tuned to Eb, except for one song, so reading a guitarist’s hands while I’m learning a song on the keys always required an extra step to remember it’s a half step down from what it looks like. Same calculations when following someone capo’ed.
I suspect he is referring to professional musicians who make enough money to be able to have various guitars with specific tunings and setups just sitting around on stage waiting to be played. Just for one song sometimes.
I stumbled across this guy experimenting to figure out what George was probably using…but George has a whole band behind him if he needs them.
I don’t have perfect pitch (though good relative pitch), so this is interesting. How does perfect pitch work for you? When you hear a note, how do you know what pitch it is? Do you visualize it as a key on a piano, or a fretted string on a guitar, for example? Or do you just somehow recognize that it’s a (for example) F#, without reference to any particular instrument?
I hear it as the note that it is without reference to a particular instrument. It’s handy for some things, but makes capos problematic. Relative pitch is much more important.
I don’t have perfect pitch; I don’t even have very good relative pitch, but my understanding is people with perfect pitch perceive a note’s quality without any need to relate it to anything else (another note or a particular instrument), just as you can perceive a particular color all by itself. Imagine someone asking you, “When you see the color red, how do you know it’s red? Don’t you need to see other differently colored objects to compare it to? Do you visualize it as a fire hydrant or a cherry or something?”
^^ Exactly. And using a capo is like saying “If red is now orange-yellow, what color will purple be?”
It also depends on how tied you are to the names of the chord shapes. I think I look at the guitar neck as a whole, even with a capo, so when playing a D shape on a third fret capo, I can easily see that I’m playing an F chord.