[surfmanjoe]

What about the IQ comparison between DA16-50 at 40mm or DA40？Both of them are same F2.8，which one is better? ignoring their price, weight and build quality factor. Thanks.

[Marc Sabatella]

I'd start by checking out the Photozone reviews of each. I suspect you'll find IQ difference miniscule compared to those other considerations.

[Eagle_Friends]

the DA 40 is one of my favorite lens in my collection. I use it like 50% of the time compare to all my other lenses.

[Luca]

As youre shooting Pentax, you should get a prime - this is Pentax' speciality. 40mm is also an excellent FOV on a digital Pentax.

[NeverSatisfied]

You know, I started to think, "How can he even compare apples to oranges like that?", but I have to reconsider... The DA*16-50 was one of the first lenses I bought when I decided on the Pentax system, and I loved it! But now, if I want something wide, I usually grab the DA12-24, and the 16-50 has become pretty much an orphan. (The 12-24 plus DA*50-135 makes a pretty darn good two-lens travel kit on most of my trips!) Something like the 40 (or I might go for the 43) would actually have been a better choice, in the long run. (Of course LBA has been a factor as well!) So my two cents, I would also recommend the prime. Good luck in your choice.

P.S. Haven't owned the 40 so can't compare, but I will say that the 16-50 has better IQ than my Tamron 28-75, which is also highly regarded by many forum members. My only minor complaint with the 16-50 (which is to be expected) is distortion at the wide end. Helluva lot bigger and heavier than a 40, that's for sure! It is a good, useful, lens though.

[Talisker]

As youre shooting Pentax, you should get a prime - this is Pentax' speciality. 40mm is also an excellent FOV on a digital Pentax.

You should get what best suits your needs whatever you shoot with - small size/weight vs much lagrer but more flexibility.
Personally I don't understand 40mm as a focal length for a prime on APS-C - its nowhere land. How many 60mm primes were made for 35mm or are currently made for so-called 'full frame' beyond a few macros? A quick look suggests I usually take longer or wider so it's not suprising I can't see the attraction

[RonHendriks1966]

You should get what best suits your needs whatever you shoot with - small size/weight vs much lagrer but more flexibility.
Personally I don't understand 40mm as a focal length for a prime on APS-C - its nowhere land. How many 60mm primes were made for 35mm or are currently made for so-called 'full frame' beyond a few macros? A quick look suggests I usually take longer or wider so it's not suprising I can't see the attraction

I would say the 40mm pancake. Lovely lens and razersharp. Much better then the 16-50 zoom (I sold my copy of it because it never came out of the closet again).

Don't forget that there where some 58mm lenses made in the past for 35mm filmcamera's and they where used for portrait. So it isn't a bad idea at all. Voightlander still makes an 58mm lens http://www.voigtlaender.de/cms/voigtlaender/voigtlaender_cms.nsf/id/pa_fdih796l4f.html

The pancake is very good for walking around town with just that camera and small lens hanging around your neck. Portraits, use within studio and some works where you need the open apperteur.

I use it quit often aldo I have some other lenses for portrait.

[Marc Sabatella]

Personally I don't understand 40mm as a focal length for a prime on APS-C - its nowhere land. How many 60mm primes were made for 35mm or are currently made for so-called 'full frame' beyond a few macros? A quick look suggests I usually take longer or wider so it's not suprising I can't see the attraction

On the other hand, a quick look at my zoom usage shows it to be the single most common focal length for me. So it's going to be personal. I find it great for casual candids and "things" in general. Being a little narrower than "normal" helps cut out the clutter.

I suspect one reason this focal length wasn't more popular with film is because 50mm beat it to the punch as everyone's first lens. 50mm makes a good compromise focal length if you don't own a zoom, as virtually no one did when 50mm ruled - 60mm would indeed be longer than you'd want if it's your only lens. And since everyone already had a 50, no reason to get a 60 *also*. But if you've already got a zoom to cover wider stuff you don't necessarily need the same sort of compromise in your first prime. Instead, you can go for one that really does something important well. I think 40mm nails that for casual people shots for me.

[Rondec]

I love the DA 40 and wouldn't get rid of it, but I end up using my 16-50 a lot more. Just walking around, it goes from quite wide to short telephoto and is sharp throughout. The pros for the DA are its small size, super fast auto focus and sharpness corner to corner. The pros for the DA * are weather sealing, quiet auto focus (albiet slower), and the flexibility of being a zoom. Bokeh to me is a toss up -- both are pretty decent, although the DA may be just a little better from that standpoint. Colors and contrast are both good.

I really think that it comes down to the question of whether you are a zoom person or a prime person. That is something that only you can know, no one else can tell you.