Originally posted by Mountain Vision Here are some comparison images with the 12-24 and mounted on the KP and K-3II.
Very interesting look and size comparison. I can see one on my KP right now. It really is the same old story. It is not necessarily a matter of either/or between the new lens and the DA 12-24mm f/4, which is still as much a very fine performer as it ever was. If one does not need the f/2.8, and does not need having WR, the DA 12-24mm will be just fine. But in my case, I do have f/2.8 zoom lenses in the range of 17-135mm plus 200mm. I have them because I sometimes do need that f/2.8 aperture. Even though my KP performs remarkably well at higher ISO settings, there is still an advantage in shooting a low light scene hand-held at half the ISO setting, or to get higher shutter speeds for action. And the new lens appears to deliver even slightly better performance wide open at f/2.8 compared to the DA 12-24mm wide open at f/4.
In keeping with what I have experienced in this regard, getting this new lens makes sense if I wish to do the same in scenes using wider angles than the f/2.8 lenses I now have. In more well-lit scenes, my DA 20-40mm f/2.8-4 Limited or my DA 18-135mm will serve very well. I don't need to haul about my Sigma 17-50mm f/2.8 or Sigma 24-60mm f/2.8, or my DA* 50-135mm when I'll be shooting at apertures of around f/5.6-11, with no need for sharp edge performance beyond 70mm . Same with this new lens. Unless I'll need WR or for low light, I would still keep my DA 12-24mm for many other uses.
---------- Post added 02-02-19 at 06:52 PM ----------
Originally posted by Sandy Hancock I might be putting my DFA15-30 on the market soon.
This is smaller, lighter, takes filters, it's warmable, and it's a *real* Pentax
If I had a K-1 and DFA 15-30mm lens, and a KP, I would be entertaining the same consideration.
That said, UncleVanya has another thread- "What crop lens is most like the FA 31 on Full Frame?" The answer is- ain't none close. So here lies the greatest advantage for the K-1. APS-C lens design cannot practically match the FOV, aperture, and smaller size of this lens or the FA 43mm f/1.9 on a FF body. A 20mm lens of f/1.8 or a 28mm lens of f/1.9 would result in a huge, heavy, extremely costly product. For me, it is in these lenses, and the FA 35mm f/2, and perhaps an ultra wide fast prime, where a FF body especially beckons.