Just to follow up on this: as mentioned, I had tested the M 2/85mm vs the 645 A 2.8/75mm, where the latter won. I now have a Takumar SMC 1.8/85mm (the desirable 6/6 construction unlike later models, including the M, which have 5/4), and while I need to compensate by at least 2 EV (which the 645 lens does not require), this lens has just about the edge on the 645 in terms of sharpness. Interestingly, the rendering is different, cooler in case of the Takumar. I'm not sure whether it needs correction or compensation. It does have something natural about it which I may prefer. Still in the early stages of testing, but the Takumar does have something going for it. I just wish it did not need to be compensated by 2 EV.

Late reply, but to add for reference purposes:

I have the HG-115C hard case, which came in a 645 A 2.8/58mm box. However, the lens that came in it was the 2.8/75mm.... The hard case is for the 55mm, though.

The HG-115 fits the 645 LS 4/135mm lens, which is not one of the most common ones.

The S90-140 soft case is for the DA 4/16-45mm lens, the aps-c one, but perhaps it was a case of double duty. I would not know of any 645 lens, however, that would fit it, that have not have their own soft case already.

Best
W

ThinkTank's Retrospective series (10, 20, 30) are deliberately npn-camera-looking bags.
And pretty

Lovely photos on the link in ypur earlier post.
Sometimes I'd like a larger format film camera, not real LF (I know my limitations), but say 6x9 or 6x17.
Truth is, I've got enough with my 645N, especially since my scanner (Screen Cezanne) is out of this world.
Truth is, there are too few hours in the day.

And the 45-85mm is not even the best in the series, although possibly the best zoom in the 645 line-up. (I have been told that the 67 55-110mm on the 645D is even better than this lens. It is also quite a bit heavier, and all manual.) It did destroy my firm belief that primes were always better, although I'm sure that theoretically they should be better, and they could be, if so designed. And that's probably also the theoretical case for 135mm lenses vs 645 ones, to be fair.

Good advice I think. I'm dreaming of a silver christmas—imprinted 31mm. I understand the quest, but these macro tubes may well be the solution.

You misread me. The perceived final quality of my 645 lenses was on the K-x, NOT on medium format. The comparison was direct, no subjective perception; and the M-lenses lost by a considerable margin. Try the 645 120mm, you'll be astonished.

Hence it is a myth, but the main point is not to generalize. I'm sure some FA lenses on 135 will beat 645 ones on a small dslr.

the 1.9/83mm came first, but in 85mm FL the 1.8 preceded the 1.9/85mm. See link

This is a myth, or more precisely, a generalization. In case of the Pentax 645 lenses untrue for many of them, as I can report out of personal experience. I posted above for the 645 3.5/35mm A-version, which produces incredible results. The 120mm is even sharper. The 150mm is not a slouch either. The 645 FA 200mm is certainly better than the M 4/200mm. The 75mm better than the M 2/85mm although not of the same quality as the afore-mentioned lenses.
The same can be true for 67 lenses, among which the 55mm and 55-100 zoom are outstanding.
This is not to say that some 35mm format lenses will not better some 645 lenses, and the FA limited series may beat the 645 lenses (I cannot tell, I do not own any), but not necessarily in resolution.
true enough. And with a medium format camera, I move slower too. Carrying these large lenses around is self-defeating unless you also carry the camera for it.

Yea, I shot for many years with the M 2.8/35mm and 2/85mm. Great travel set.
Sold both, and my beloved KX (but tempted sometimes to buy it back).

Still, having invested in the 645 system—which I love—I find I have less use for the equivalent of the 35mm (which is 55mm). A change apparently in my needs, nothing to do with the lenses I have.

But I still bought the 1.8/85mm today and cannot wait to see it (I haven't received it yet). My experiences with the (early) 1.4/50mm Takumar were such that I could not resist. And in anticipation of a FF Pentax, I should have the 31mm too, but pending lottery results, may settle for either 30mm or (more likely) a 35mm Takumar. Yes, they are not autofocus. If I really need that, I'll use the 16-45mm DA on my K-x.

The 645 can be heavy, I need something for daily carry. This 1.8/85mm will do the trick.

There is a distinction between the 85mms, and the 1.9 is not the earlier version, but the later Takumar one. Ultimately, though, IQ depends on your lens and on your lens/camera fit. And above all, your eye.