I read your Original Post last night just before I fell asleep, but I wasn't sure what to reply.
I've owned every lens you mentioned.
Keep in mind that my latest body is the K-5 IIs, so I can't speak about performance on the K-1 or any other more recent bodies.
My first thought is you don't need the FA35/2 - especially if you're keeping the FA31. I owned two copies of the FA35 concurrently, so I really wanted to love it. I ended up selling both because I couldn't get adequate IQ wider than f/2.5. You could re-aquire one easily enough if you later regretted it, or you could get it in DA35/2.4 guise instead. In fact, I've long argued that the DA35/2.4 (I've used one) is better anyway - it delivers nice round bokeh circles wide-open at the IQ sweet spot.
Originally posted by Pentax Syntax Don’t toss the 24-90 FA if you have a good copy. It’s light weight and optical qualities make it a keeper. The 24 wide end is hard to duplicate with any of the modern zooms except the heavy 24-70 2.8. The FA 35 is a great lens but duplicated by what you have. Just my two cents.
This was my next thought. If you have a good copy of the FA24-90
count yourself lucky! It was my first "non-kit" lens and I was rather fond of the travel images it produced. Many people apparently have bad copies of this lens - mine has frequent AF problems and developed optical issues after its fall from my cursed old green Canon backpack (the horrible design unzipped by itself while wearing it, and the FA24-90 was its unwitting victim)!
I may be romanticizing this one a bit, but I still have great shots from it.
As for the rest:
I trimmed my kit down to "only" 12-16 key lenses (plus a few of Pentax' great, cheaper lenses like the F24-50/4):
I sold the 3 amigos
, and effectively replaced them with the FA*24, FA*85, and F*300. As great as the FA Ltds are, I've been fine without them. The FA*85 and F*300 are now my favorite lenses. The FA Ltds are still amazing for their size, and outstanding in their own right. But somehow these widely-spaced F/FA* focal lengths suit me, and sometimes I carry only these three lenses.
Oddly enough, I don't have a single prime between 29mm and 84mm anymore (except for the A50/1.7, which I've lent out). It seemed that I didn't get enough interesting shots between these focal lengths. Of course this range includes
all 3 FA Ltds. They're
all wonderful, but
they weren't doing enough for me. I think if I ever need primes in this range again I'll know it, and they're readily available. I suppose if I get a K-1 I'll be content with a single ~24-80/2.8 zoom to cover this.
I
really liked the FA20-35/4, but managed to let go of it when I got the FA20. I don't think I regret this either. I still have faster FA20/*24/28 lenses, plus the DA* zoom.
The FA*24 has become an essential part of my kit. The fast aperture makes a big difference to me, allowing me to leave behind the FA20, FA28, DA*16-50, and (often) even the DA10-17. But I confess it's tricky to wrest what I want out of it sometimes. Like the fine FA31, it can take extra work to avoid getting ~ordinary looking images from it.
TLDR; What I actually
did is sell the FA35, the FA20-35, and ~lost the FA24-90 to an accident (without replacing it). I kept the FA20 and acquired an FA*24.