[GeneV]

If I'm really looking for compact and light in this range, I carry the 20mm and the 40mm limiteds. Not weatherproof, but on a small body, it is a terrific combo with both speed and light weight. On a trip four years ago to Spain, those two on a Kx were the vast majority of my shots. Perhaps that does say something about the usefulness of that range as a zoom.

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Last edited by GeneV; 01-05-2015 at 07:39 AM.

[david94903]

I spend most of my time towards the 16mm range on my 16-50mm lens. So based on needing a physically smaller lens size, I ended up purchasing a HD 15mm f/4 Limited to be my new daily driver. I love the lense, sharp, great color, small size. The only thing that'd make it better would be if it went to f/2.8. But then it wouldn't be small anymore. Oh! And weather sealing.

[Rondec]

The 16-50 is a very nice lens. Biggest negatives are flare resistance and fringing, but it is such a handy range to have, particularly the 16mm. The only lens I could see substituting for it would be the 16-85, because I shoot a lot of landscape and having the wide side available is awfully handy. If you can deal with the smaller range and a little slower aperture, the 20-40 does look like a nice lens as well.

[Stoogie]

I own the 16-50, and have tried the 20-40, and I'd take the DA* for the constant aperture alone (it's a real pain when you've got to change settings every time you zoom in). Additionally, the 16-50 is longer, wider, apparently better sealed, and isn't really that much bigger. The 16-50 does fringe a lot, but if you can stop down a bit that cleans up pretty quick, and if you can't it's fixable in post. It isn't wonderfully sharp wide open, but sharpness isn't everything, and other than that the lens takes amazing images. Once you stop it down to f4 or so you'll have to soften up your portraits a bit to hide all those pores. That being said, the 20-40 looks great, is a bit more inconspicuous, comes in silver (if you want to negate said stealth advantage) and has a DC motor rather than SDM (though the SDM issues have apparently been fixed now). Overall though, I'd say the 16-50 is the more versatile lens.

[emalvick]

Short of the WR, I chose the Tamron 17-50 because of its size vs. the Pentax and Sigma offerings. I've used it in wet situations and haven't had problems. I've used the primes in wet situations too without issues. When the weather is questionable, I'm not even trusting my WR lenses. They aren't necessarily water proof.

Otherwise, It all just depends on what you anticipate shooting:

If you got the 20-40, would you need other lenses to make up for a more limited focal range?

You mentioned you considered the 15 mm. It sounds like that might have you lean towards the 16-50. However, unless you really shoot that wide often, stitching together panoramas work well too. I recently got both the 15 mm and 21 mm. I've not used the 15 mm much, yet. I like shooting wide (I shot a lot of 17 mm shots with my Tamron), but I like the 21 mm and can make it work for most situations. The 15 mm gets used about as often as I used to use a 10-24 mm zoom I have. It's great when the situation calls, but it doesn't call often.

Primes and Limiteds are great options for size, but they don't have the WR, and they can be frustrating to switch out if you need that (again depends on your shooting).

Last, have you considered a 18-135. I know it isn't as high end as the 16-50 or 20-40, but it is WR, versatile, and not much worse than a 16-50. Another thread even shows examples where one could say the 18-135 is mostly as capable as the 16-50. You do lose the speed, however.

Speed and size are always a trade off.

[john5100]

I love my DA* 16-50mm. It's my most used lens but the Sigma 18-35mm F1.8 looks terrific also.


Robin and Justin Wedding by John Rudolph Photography, on Flickr

[starbase218]

Between these two, for landscape shooting? Definitely the 16-50. The 20-40 may be a great lens: small, light, excellent build quality, DC autofocus and all that. But if I'm out shooting landscapes, I want decent wide-angle. That's the 16mm of the 16-50, which you simply don't have in the 20-40. So if it can't do that, what's the point?

And, yeah, at 16mm and f/2.8 it's not the best performer. But stop down to f/5.6 or smaller and it's great once again.

edit: or.... get the brand-new 16-85. Also WR, 16mm, DC autofocus, and early results look good.

[Dice]

Between these two, for landscape shooting? Definitely the 16-50. The 20-40 may be a great lens: small, light, excellent build quality, DC autofocus and all that. But if I'm out shooting landscapes, I want decent wide-angle. That's the 16mm of the 16-50, which you simply don't have in the 20-40. So if it can't do that, what's the point?

That's a good point for the OP. Check to see how often your shots are at 18? Did you wish you could go wider. I had the DA15, 21, 35. And I found that most of my landscapes were at 21. only used the 15 for more dramatic affect and that wasn't very often. I ended up selling them all. If PR comes out with a short range WR wide angle zoom I might consider it. Anyway something for the OP to consider.