The "you're kidding" was simply a bit of good-natured teasing on my part (feeling my oats at that point....
)
As for the in-and-out of focus... part of that, I know, is because some of the film elements had degenerated over the years, being of the old nitrate stock which required careful preservation (otherwise, it could do any of the following: combust, melt, become very grainy, or simply turn into dust; a good example of the last being when my then-wife was working at a movie theatre, and we came across a bunch of old silent film trailers up in the attic when cleaning it out... and -- dammit! -- because they hadn't been taken care of properly, they were either fused together or simply canisters of dust...)
Another part of that -- especially the scene where Mary Philbin's character unmasked him -- was, I think, meant to represent her shock... a near-syncope at having this walking corpse (as he would have appeared to her) approaching her.
And yes, Lon, Jr., was in both some very good films (High Noon, for instance, or The Wolf Man) and a lot of very bad ones....