Is intonation under slurs harder than detache
I find that my intonation is less accurate when I play slurred notes than when I play them separately at the same speed. Is this normal? What might be the cause.
a good way to practice passages where intonation is a problem is to play all of the notes slowly and staccato so you can really listen to make sure everything is in tune. it's easy to overlook accuracy when the notes are slurred so removing the slurs when you practice keeps your intonation honest.
Changing the bow pressure will change the pitch. If your ears (or the listener's ears) are sensitive enough they might detect the change. Identical fingering but with less pressure near the tip than the frog might be detectable.
It might be that you are concerned about keeping your bow moving continuously and therefore having to think of multiple things at once is making it harder to focus on intonation. If that's the case, practice that bit slowly and break it up into small and manageable goals. If you play fewer notes at a time you may find it easier to train your fingers.
In faster slurred phrases, the fingertip may not sink into the string so much. I find that in trills, for example, I may want to aim the trilling finger a little further than usual.
Try separating each note (still all in one bow), stopping between each note to prepare the next finger. Once you master this you will see an improvement with your slurring.
All good points! Violin intonation is a more delicate matter than I imagined. So many factors.