Originally posted by causey
You, Brutus? You, the passionate advocate of the DA 40mm? I bet you'll regret it in a couple of months. Regret made me buy it a second time.

Don't worry, I also bought a 50mm to replace it.
The DA 40 is a *magnificent* lens, but so is the FA 50. In fact what happened was I was able to sell one to buy the other.
This is why I buy things used... I'm sure I'll see a 40 again. If Pentax makes an ASPC evil, there's no sweeter combination I could think of than the DA 40 + on a compact digital.
The kit is *not* the 40. They might be indistinguishable at f8, but the DA 40 is pretty spectacular at f2.8-f4 (where the kit either sucks, or can't do). However, what I realized is that when I need a normal, I tend to stop down to f5.6 and just fire away. Because of this, I wasn't really using the 40 to it's potential. And before the 40, I owned the FA 50... and like you, I began to regret selling (just it was the 50).
Unlike a lot of people... I really like 50mm on aspc. It's a *little* short for portraits, but at the same time, 1/2 the price of traditional portrait lenses.
If I had all the money in the world, I'd own the whole DA ltd. line up. However, since I primarily use fast primes in that range for portraits, I found that the FA 50 was a better focal length for me, and the speed didn't hurt, either. I didn't have enough money to buy a 50 on top of owning the 40, so I swapped.
If I decided I didn't want the 50 any more, I'd likely sell it for the 40. But I need one fast prime for portraits, and my 70-210 only works for low-DOF stuff if I have a lot of space.
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I was also advocating the DA 40 as a reasonable alternative to the FA 43... but that limited thing is a whole other matter. It took me some time to realize it does not need to say "limited" on the barrel for it to be a top-notch lens... and I really think that the 50 1.4 is a top notch lens.
What I'm actually lusting for is a DA ltd. version of the DA* 55.