Is it better to lecture with a board or a document camera? I will be teaching my first class this fall. The course will be an undergraduate engineering course, so there will be some derivations and other math.
I am trying to decide if I should present with a white board, or with a document camera &amp; projector.
Most people in this SE can probably speculate on which is better, and for what reason.
I could present so very elaborate arguments also, one for each side. However, elaborate theories are not what I am interested in.
Has there been any published research to show that one is better for student learning than another?


Edit:
There is a question of what a document camera is. There is a wikipedia page about it.
Just to summarize what it is, when lecturing, instead of writing on a black board, you write on a normal piece of paper. A camera looks at the paper as you write, and projects it with the same sort of projector you would use for power point. Here is what they look like: 
When lecturing with these, generally the professor will sit behind the desk, and talk as normal, just write everything on paper and the students can see it. It is similar to using transparencies, like my physics professors used in the 90's.
A nice comment by @Alchimista

I've personally found teacher writing on board more interesting than those projecting. Is matter of flow, which is more natural in the first case. It seems to me that projecting was invented to communicate time effectively without omissions, and resembles more a briefing than teaching. Obviously projected slide can be used in parallel, when complicated graphics plays a role. I won't draw the schematic of an eye if I can show a nice figure of it, for instance.

This agrees well with my assessment; as a student I prefer instructors who use the blackboard. However, teaching with a doc-cam is much easier to learn than writing on a black board. I would speculate that because the interaction between professor and student is stronger using a board, that it is more effective. I assume that there has been some outcome bases assessment of this by someone, and that they published at least an abstract. I posted this here because (1) I want make a choice based on something more solid than my feelings, and (2) it might help others to teach more effectively.
The issue of how technology effects communication and learning is definitely of interest, from a linguistics perspective or from an educational perspective.  Most importantly, at the chalkboard it is easy to point.  A document camera allows pointing, but it is awkward.  Tablets make pointing very hard (I learned this the hard way).

This is not at all my area, and I have not vetted the following papers.  They look interesting, and perhaps give you a start in accessing the literature.  Mostly I found studies of tablets, but did find one discussing the advantages of a document camera for some students with disabilities.


Maclaren, Peter, David Wilson, and Sergiy Klymchuk. "I see what you are doing: Student views on lecturer use of Tablet PCs in the engineering mathematics classroom." Australasian Journal of Educational Technology 33.2 (2017).
Maclaren, Peter, David I. Wilson, and Sergiy Klymchuk. "Making the point: the place of gesture and annotation in teaching STEM subjects using pen-enabled Tablet PCs." Teaching Mathematics and its Applications: An International Journal of the IMA 37.1 (2017): 17-36.
Williams, Jocasta, and M. F. Fardon. "Lecture recordings: extending access for students with disabilities." ALT-C. 2007.