When compared to in-person lessons, teachers and students will have to deal with limitations of what they can see through a camera. It is very important to frame yourself and your instrument to get the most benefit out of your lesson experience. Depending on the instrument and available devices, your method of framing yourself and your instrument will vary slightly.
Students should ensure that their best camera angle captures themselves (above the waist) and their instrument. Since you are more likely to be performing your assignments repeatedly, it is crucial that the camera placement can capture the information that is important for teachers. Even your facial expressions and body language provide your teacher valuable insight on how you are handling the difficulty of your assignments.
For voice and smaller instruments, ensure that your teacher can judge your posture and hand placement from your chosen camera angle. Avoid being too close or too far from the camera.
For students who play on larger instruments, such as a full-size acoustic piano or drum kit, try to fit as much of the instrument in your camera angle and focus more on the hands. If your piano has a ledge along the sides, you can lean your phone or tablet on that ledge and get a good angle of the wrist and finger positions (as shown in this article) If you can raise the camera a bit higher, you can also get a good view of all the keys for your teacher to see. Drum students may want to use a USB webcam or some type of phone/tablet stand to get the full angle of drum kit. Some good examples of drum kit angles can be observed in the video below by professional drummer Benny Greb.
Teachers who take a more observational and reactive approach to online lessons may only need to frame themselves with their instrument when required to demonstrate something on their instrument, such as proper hand placement or finger technique.
For voice and relatively smaller instruments, such as a guitar or violin, framing yourself from the torso up should be sufficient. This way, your student can see your posture with the instrument and the placement of both hands.
For those who use larger instruments, such as an acoustic piano or drum kit, you may want to focus on the instrument itself. For example, a camera placed above or to the side of a piano should capture the length of the keys and the general hand placement or posture. For a drum kit, a camera placed behind and over the shoulder of the drummer will allow all the drums and cymbals to be present in the capture frame. Experiment with your device placement to get the most comprehensive view for your student without sacrificing ergonomics, and take advantage of multiple cameras if possible.