Quote: but they are not digital designs, it's still just plain old FA design with some added coatings...
True. I guess the question is, why is this distinction important? Does it in some way make the lens less usable on digital than they would be otherwise? Focus speed - now that's a distinction worth making.
Quote: Lens is a lens, no matter what. No matter what size of medium you put it on. The enlargement provided by lens remains constant!
This is true also, but has no real world relevance whatsoever. The amount of "enlarging" done by a lens is not what determines the appearance or quality of the picture. As I said before, what matters is the FOV and the resolution provided. A 5-50mm zoom lens designed for a P&S with a 6X "crop factor" might produce a much smaller image at 50mm than a 300mm lens designed for FF. But if the resolution of the sensors are the same, and the lens resolves well enough to take advantage of the senor resolution, you're not going to see any benefits whatsoever to the greater "magnification" the 300mm lens provided. It's simply a myth to assume you will. There is no way to tell in the example I just gave which system will in fact perform better with regard to any aspect of image quality (except of course high ISO noise, where you'd assume the larger sensor wins - but that has nothing to do with any difference between the lenses).
Now, one might wonder how *typical* it would be to have a shorter lens for a smaller format to have resolution to match the longer lens for the larger format. I don't have an answer for that, and I doubt you do either. What I can say is that I certainly don't see any reason to simply *assume* that the long lens for the large format will have more real resolution than the short lens for the small format - particularly when we are talking about the relative small differences between 35mm and APS-C as opposed to the relatively large differences between 35mm and a P&S.
Quote: look at FA35/2 is it big?
Not really, although it *is* bigger than any 50/2. But you're probably right - the *size* might not be as significant a factor at the 35mm focal length so much as the cost. AFAIK, 35/2's pretty much always cost much more than 50/2's.
Quote: what if one doesn't like compromises?!?
That's my point. 50mm *is* a compromise (between FOV, price, and size) that happened to make sense on 35mm film cameras. Why get so hung up on reproducing one aspect of that compromise (FOV) on APS-C? I mean, if it were the best possible focal length for some purpose, that would be worth reproducing. But it isn't really - it's just a decent focal length if you are trying to design a small cheap prime for someone who probably doesn't own any other lens in any other focal length. In today's world, there just aren't that many people fitting that description.
Quote: High ISO can deliver handholdable shots, but can't deliver narrow DOF that appertures of f2, f1.7, 1.4 and 1.2 could.... IMHO, you said it yourself
I did indeed. I also added that the need for speed was reduced, not eliminated, but that with reduced need comes reduced demand. In the absence of usable zoom lenses, and in a world where f/2 or better was needed to get handheld shots in even moderately low light at ISO 400, demand for such a fast 50 was *enormous*. Pentax sold a zillion of them because virtually every single person who bought a camera bought a fast fifty with it. I doubt Pentax would sell even 10% as many fast 35's to today's DSLR owners as they did to yesterday's 35mm SLR owners. That's got to factor in to any decisions on which lenses to produce.
Quote: Zooms are big!! and require more engineering, more moving parts, more things to break... I'd rather have bag full or primes, size of FA28, 35 and 50...
Hey, don't get me wrong, I'm not saying zooms are the answer for everyone. I prefer primes too most of the time. I'm just trying to be realistic about what the demand for these lenses really is. Primes are a much tougher sell in today's market than zooms are; that's just how it is. And with prime sales being down overall, it doesn't really surprise me that a lens manufacturer would concentrate on higher margin "specialty" primes as opposed to the more general purpose sorts of lenses they used to crank out and sell cheap on volume.
Basically, the way I see it is, Pentax is not stupid. If they thought there was a huge demand for primes with the specs you describe, and they could meet that demand at a price point that would sell in the sort of numbers necessary to turn a better profit than the lenses they are producing instead, they'd be there in a minute. Wouldn't anyone? I don't think we need any sort of conspiracy theories to explain why this isn't happening. I think it is as simple as I am saying - they aren't doign this because the demand probably isn't there for lenses that would probably cost what these lenses would have to cost to make money.