Are there any Magic Lantern Guides, System Handbooks, or other publications for Pentax MF? There's just about any kind of book you can think of for Nikon, and I have many of them
Google comes up short, i´ll bet that something has been made back in the day. Then again, it´s a shutter, viewfinder and aperture so the table of content might cut it a little short for a book. Best bet is to use online forums.
The wonderful thing about those cameras, esp the P67, is that you DIDN'T need a guidebook. Just basic settings, choice of lenses, etc - no
silly bells & whistles beyond what a few pages of owner's manual or a brochure described. The reputations of specific lenses are best known
by simply asking current users. ... But I've never seen a guidebook for em.
There are PDF's of instruction manuals for Pentax 67 and 645 series cameras available on the web. Like Drew said the Pentax medium format cameras are very easy to use. I used to own the advanced 645 Nll and it was simply a joy to shoot.