Backwards step? Perhaps but tempting

[cdd29]

Hope this is the right group (if not please move), but long story short a Mamiya 645DF, Leaf 22 digital back & a few lenses have popped up locally for sale. I've always been fascinated with medium format & had the pleasure of using a Pentax 645z for awhile. For reference my current gear includes a Pentax K-1ii & Sony A7R3 and I do have access to a Fuji GFX 100s.

I do primariy landscape & night photography (cityscapes, some light painting), static still life studio stuff & occasionally some portraits, so I usually don't require a fast camera. I'm very tempted to grab this, if the numbers work & if this actually makes sense...

The two things that draw me to this are
1) more of a 'full frame' medium format vs. 'cropped' medium format of current Pentax & Fuji offerings and more improtantly,
2) CCD sensor (22mp). I've often heard people say they like what comes out of a CCD sensor color wise over a CMOS sensor, looking at people that have used both the Pentax 645D (40mp CCD) & 645z (51mp CMOS) and my personal experience with a Nikon D-70 (if I remember correctly) & it's CCD.

I know this is a 15+ year old set up and much slower in about every aspect of a newer camera, but for what it would be used for that wouldn't be a problem. Just trying to figure out if it would a worthwhile move. Plus, most would probably agree that CMOS tech has surpassed CCD in most aspects (CCD's are still used, though primarily astro cams for what I've read.) There's not much to go on as far as articles, especially looking at low light performance & dynamic range, which I would bet wouldn't be as great as I'm hoping. Thoughts from people that have used a similar set up?