Originally posted by Rondec Macro lenses are all good, because of their flat field, right? I mean the DA 35 macro, 50 macro and the DFA 100 macro are all highly regarded lenses. But the DFA 50 macro is only an f2.8 lens, which could be a negative for some folks. You had mentioned earlier having lenses that do everything well, but typically, lenses that are good at portraits are not necessarily great for landscapes.
Most 50mm lenses will be decent at f2.8, but the question is how they do at apertures wider than that.
In the case of the present Pentax system, the 50mm choices in AF for new equipment is an f/2.8 macro and an f/1.4 that was designed in the late 1980s, or very early 1990s and which is, at best, less than stellar (mine is abysmal wide open, and this is after a repair for optical issues).
The DA doesn't cover the full frame (at least mine didn't), and I found it had pretty rough bokeh.
It's all well and good to say these lenses exist, and therefore we should be falling all over ourselves with gratitude, but a 1.4 lens that is so soft as to be unusable wide open is practically useless, as is a lens that is reasonably sharp wide open but doesn't cover the frame.
My A50/1.2 is significantly better wide open than my FA50/1.4. If I didn't want to have autofocus from time to time, I would be happy with the A series lens.
Then again, if I didn't want to get from point A to point B in a reasonable amount of time, I would probably be happy with a burro.