Originally posted by DSLRnovice A local store has this one fo $90US and some M 50s. The reviews on this site for the 1.4 are very good, but don't know how many are about FF quality.
I think I mentioned the A series. The thing is, the 50mm f1.4 and 50mm f1.7 both have long lineages, since the M series. There have been tweaks and updates, so the newer ones have more automation and features, possibly better lens coatings, but they will be in the same ballpark optically. I think the 50mm A series is optically very similar to the M series, but it has auto-aperture and I think that's worth it.
You can check detailed user reviews here:
Full Frame Prime Lenses between 42mm and 58mm | PentaxForums.com
Just find the lens and click it to see the user reviews to get a good idea.
I don't think any Pentax 50mm will
disappoint you, none of them are terrible. But some might be above and beyond
Originally posted by DSLRnovice Regarding the 28-105 WR, would it at 50mm be as good as the DFA 50/2.8 macro?
I don't have those lenses to do a test, but I don't think
any zoom lens will be as sharp as a macro prime. But its a question of what is acceptable. If you have higher standards for what is acceptable, you will have to pay more money to reach them. DA 50mm f1.8 is sharp enough for
a lot of people. But clearly a number of people are willing to pay 10x its price for more correction, better colours, nicer bokeh, faster aperture, WR, QS, better construction, faster AF, etc. etc.
Macro also has the advantage that you can use it for product photos, insect macro, and so on. Its good to have one macro prime in your kit. There are also older versions, like F and FA 50mm macro. Basically, there is no shortage of 50mm lenses and you will be hard pressed to find a bad Pentax 50mm
We had threads in the past of people comparing different 50mm lenses. By aperture f4 they are all so good almost nobody could guess which is which
Tl;dr: Get the A or F or FA series. f1.7 are a little cheaper. f1.4 are brighter, but might be a hair softer until f2.8. Macro are usually brutally sharp, but are bigger and have slower AF