The field is there; we didn't "construct it". — Janus

That-s what you see. A field. The other three guys see something more. You might think your view is detached of observers, but it's still a view. That's the human being condition. We all want our views to be objective. But all we have are views. Worldviews. For different people or groups the views can diverge. One's objectivity is the others fantasy.

So if we sent 1 photon at a time at the slits and try to detect which slit they go through it would collapse the wave function whether or not a person checks the hard drive of results to compare against the background pattern? — TiredThinker

Strictly following the axioms of QM, no. Only when an observer measures the one photon, be it directly or via memory disks, the wave function collapses. As hard to digest this might sound, a proponent of observer induced collapse can always keep this up. Strange stuff like the many worlds interpretation (to preserve unitarity of the evolution of the wave function, relocating non-unitarity merely to the branching points where the wave function splits in the states that were superimposed before a measurement, although it looks as if unitarity is maintained), and decoherence (which only seems to solve the problem of wave function collapse) are invented to solve the measurement (collapse) problem.

But even the friend of Wigner's friend who observes a person looking at Schrödingers can, can always say that it is him or her that causes collapse, no matter what the guy observing the cat directly, or the guy that observes this guy feels or thinks. Only in a theory with non-local hidden variables, the situation can be interpreted as a real, physical collapse, independent of observers. So let's hope they are discovered.

If the wavelength is large though, there will be more free electrons (if there are more than one). If the wavefunction of the electron extends over the whole material in question, you will make a better chance with large wavelengths.

It is not about atoms. Why can't a single free electron interact with radio waves or infrared radiation in the apparatus?
2h — SolarWind

I can interact. Why shouldn't it?