[c_kamb]

I use K-3II and 16-85 all the time for hiking and I hike a lot. Weight is not a problem if it's attached to the bakcpack straps.

[WPRESTO]

Good many recommendations for the 16~85mm (the extra WA is very useful) or 18~135mm (extra tele reach is useful). Bulkier, but if you want more long-end reach a used Sigma 18~250mm could be a bargain zoom, as it was discontinued when replaced by an 18~300mm version.

If you want inexpensive + compact/light + excellent IQ, consider an FA 50mm f1.7. A good clean example can be had for $100 or less.

[Kozlok]

I too recommend the 16-85. I also really like the Blackrapid straps. Either the Sport if you are not using a pack, or the Backpack model to attach to your backpack.

The 16-86 is $530. If budget is a concern and you do not need WR, the first-generation Sigma 17-70 2.8-4.5 is 98% as good as the Pentax and available used for around $150. I’d get the Pentax just for WR though. You can keep shooting in the rain that way.

[08amczb]

DA16-85 or DA18-135 is good. The 18-135 has more reach and it's smaller and lighter. The 16-85 is wider, and has a somewhat better IQ.
I have only the DA18-135, but I use it for skiing and travelling where I like the long end of it, and I solve the wider shots with panoramas.
The DA20-40 has much better IQ, but it has a very limited zoom range, although these are the most useful focal lengths on APS-C. I don't have this lens, because I covered the range with faster primes.
My goto primes are FA*24, FA31Ltd and FA43ltd, these are small, fast and covers my needs. I like my primes more, than my zooms. The FA*24 is perfect indoors lens and the FA43ltd is perfect outdoors lens.
Consider your budget and consider buying used lenses.

[AyeYo]

16-85 is the obvious choice if it's in your budget and image quality is the most important factor to you.

I didn't see you mention what type of hiking you do, whether casual through the woods or mountain scrambling. Personally, I just bring the 18-50 kit lens when hiking. It weighs nothing, the hood is flush-mount to make it even smaller, the IQ is perfectly tolerable given the other advantages, it has WR, the focal range is great if you're not trying to shoot small or distant animals, and, most important to me, when I inevitably slip on a rock while scrambling and smash it - I won't have to cry over it and hold a memorial service. The 18-135 looks like another good cheap option if you want the reach to be able to better get distant or smaller animals.

[mapguy]

16-85 is the obvious choice if it's in your budget and image quality is the most important factor to you.

I didn't see you mention what type of hiking you do, whether casual through the woods or mountain scrambling. Personally, I just bring the 18-50 kit lens when hiking. It weighs nothing, the hood is flush-mount to make it even smaller, the IQ is perfectly tolerable given the other advantages, it has WR, the focal range is great if you're not trying to shoot small or distant animals, and, most important to me, when I inevitably slip on a rock while scrambling and smash it - I won't have to cry over it and hold a memorial service. The 18-135 looks like another good cheap option if you want the reach to be able to better get distant or smaller animals.

Thanks for all the replies....

Im way behind what Pentax is offering now, I am way behind the times, but love all my old Pentax prime lenses that still work, just looking to add a few new ones.

I should have been more specific, I'm just doing day or weekend hikes, but am trying for keeping things small and light if I can. But part of it was to find a lens that I keep on the k3-II all the time.

Im not giving up the 80-200 f2.8 or the 300mm f4.5 anytime soon, just have nothing new and AF to keep on the camera when I'm not shooting spots stuff.

[UncleVanya]

Thanks for all the replies....

Im way behind what Pentax is offering now, I am way behind the times, but love all my old Pentax prime lenses that still work, just looking to add a few new ones.

I should have been more specific, I'm just doing day or weekend hikes, but am trying for keeping things small and light if I can. But part of it was to find a lens that I keep on the k3-II all the time.

Im not giving up the 80-200 f2.8 or the 300mm f4.5 anytime soon, just have nothing new and AF to keep on the camera when I'm not shooting spots stuff.

With this in mind...

Smallest lightest lens that is a zoom is likely 18-50 (not 18-55). Reviewed on this site, can't post the link at the moment.

Most versatile and not too heavy (subjective) are the 18-135 and 16-85 lenses.

There are many other options. Do all lenses exist, 18-250, 18-270, etc. But these get heavy.

[ThorSanchez]

Thanks for all the replies....

Im way behind what Pentax is offering now, I am way behind the times, but love all my old Pentax prime lenses that still work, just looking to add a few new ones.

I should have been more specific, I'm just doing day or weekend hikes, but am trying for keeping things small and light if I can. But part of it was to find a lens that I keep on the k3-II all the time.

Im not giving up the 80-200 f2.8 or the 300mm f4.5 anytime soon, just have nothing new and AF to keep on the camera when I'm not shooting spots stuff.

I'm a big fan of the DA15 and either DA40 or 40XS as a very lightweight/small size kit.


The only thing it is missing is weather resistance. I've never understood why Pentax hasn't come up with any WR versions of their small limited primes. Even with small weight/size increases something like a DA15 WR would be great. I suppose they think that's covered with the 20-40.

[UncleVanya]

I should have been more specific, I'm just doing day or weekend hikes, but am trying for keeping things small and light if I can. But part of it was to find a lens that I keep on the k3-II all the time.

One more time into the breach!

It sounds like you want a good walkabout zoom that you can use as a general purpose tool as well as for day hikes. You want something light and reasonably portable.

I suggest the 16-85 or 18-135 unless you feel these are too big and too heavy. If they are then the choices really are: 18-50, 20-40 limited, 18-55 (many versions). Of the first two the 18-135 is lighter (slightly) and smaller. It has a reputation for lacking border sharpness over about 70mm, but the center sharpness is excellent through the entire range. So if you are using typical framing with telephoto you can get good sharp pictures of your subject even at the telephoto end. The 16-85 is very sharp - rivaling the 16-50 DA* lens in all but aperture speed. The 18-50 seems an improvement over the 18-55 versions, it is also the lightest and smallest of these. The 20-40 isn't as light as the 18-50, has a shorter range, but it is also a limited lens and offers f/2.8 on the short end and only f/4 on the long end.

Personally for an all arounder I'd be going for one of the first two - unless you know you don't need so long of a range. If you can live with it the 18-50 or 20-40 would be a nice light option.

If you can live with a Prime lens then the DA 35 macro is a good contender for the best single all around lens since it offers the normal lens perspective with full macro capabilities.

[normhead]

To me it's simple 16-85 if you have the money, and can carry the 55-300 for longer focal lengths, or 18-135 if you don't. AT 16mm the 16-85 is more specialized, the 18-135 is more general purpose. The difference in price reflects the difference in quality.

[SteveinSLC]

If you wanted to carry two lenses, one more option:

20-40 and the
DFA 28-105

Both very high quality and on APS-C coverage from 20-147.

[Des]

Like most other posters, I've got a number of lenses that might come with me on a walk: in zooms, DA 12-24, DA 20-40, DA 18-135, DA-L 55-300, DA 55-300 PLM, and in primes 35, 43, 50, 77, 100, 300, 400. I take different combinations on different walks, depending on the conditions, what I feel like shooting or what I expect to find. Birds and wildlife are high in my priorities, so I nearly always take a telephoto lens. Even the versatile and capable 18-135 often isn't long enough for birds. Sometimes I just go with a prime or two (35 and 300, or the 50 macro, or the 100 macro), and you certainly see things differently that way. And some of these primes are so good that they can just make something happen - the 77 and the 100 particularly. But much of the time it's just too limiting (for me anyway). So my default combination is DA 18-135 and DA 55-300 PLM. That covers most things at a total of about 900g, with WR. The 20-40 + 55-300 combination works very well too (the IQ on the 20-40 is in prime territory), and shaves about 200g - but it means more lens changes, and I miss the wide angle. I have used the DA 12-24 + 55-300 combination too - the 12-24 is about the same weight as 18-135, and is bulkier and not WR, but satisfies my craving for UWA.

So my points out of this experience are:
- Primes bring a different shooting mindset. You have to be prepared to miss a lot of shots with a prime-only or prime-oriented kit, in the hope of getting a handful of special ones. The quality of zooms has improved a lot in recent years, so a zoom doesn't involve the same degree of compromise it once did.
- WR is peace of mind. For hiking, it should be a priority, unless it's sure to be dry.
- If you prioritize WR, the choice becomes simpler. Third-party lenses are ruled out. Skip the kit lenses unless the budget is really tight. Amongst zooms, that leaves DA*16-50 f2.8, DA*50-135 f2.8, DA 20-40 Ltd, DA 16-85, DA 18-135, DFA 28-105, DA 55-300 (screwdriven WR version or PLM), DA*60-250 f4, DFA 150-450 and the DFA f2.8 zoom trio. For hiking, most people would forgo the extra weight and bulk of an f2.8 lens, and the DFA 150-450 is a 2kg beast. Amongst primes, WR options are limited: DA*55, DFA 100 macro (a wonderful lens for general use as well as macro), DA*200 f2.8, DA*300 f4, DA 560.
- Out of those WR choices, the options in the wide to normal range (on APS-C) are 20-40, 16-85 and 18-135. You've heard the arguments for one or the other of these. They are all good lenses. All have modern coatings (good flare resistance), quiet AF and QS. For prime-like IQ, a little more speed, and a little pixie dust in a light-weight package, the 20-40. For the extra width, a useful range and better corner-to-corner sharpness (with a little more weight and bulk), the 16-85. For the do-it-all lens (and a lower price), with surprisingly good resolution, the 18-135. You can't really go wrong.
- If you shoot birds or other wildlife, definitely get one of the 55-300 WR lenses. The PLM is fast-focusing, quiet and has better rendering. The screw-driven lens is noisy but just as sharp, about one-third to one-half stop faster, and a bargain buy now. These won't displace the wonderful F*300 f4.5 - there's a place for both in your kit.
- I love my K-3, but I find the lighter weight and flippy screen of the K-S2 often make it a better option for hikes. It's worth considering. Or a K-70 or K-P.

[Sandy Hancock]

I don't own either the 16-85 or 18-135, but given its smaller size and bigger range I would suggest the latter, with the DA15 Limited in a plastic bag in an accessible pocket of your rucksack.

Personally, I'd take my DA*16-50 and DA*50-135.

If you wanted to carry two lenses, one more option:

20-40 and the
DFA 28-105

Both very high quality and on APS-C coverage from 20-147.

Correction: from 20-105
Focal length works the same regardless of the image circle size

[mikesbike]

The old pancake from the film days was probably a 40mm f/2.8 lens. The closest to that experience would be the DA 21mm f/3.2 Limited, which would actually provide a more versatile and wider field of view, without being overly wide. But it does not offer WR and of course you are asking regarding a zoom lens. Normally, for general shooting, I would say the DA 18-135mm. It is a very good choice for excellent zoom range for both landscape and an opportunistic wildlife shot. It is amazingly compact, yet very well built. But if you want to emphasize edge-to-edge sharpness at all apertures across its zoom range, and a wider FOV, mainly for landscape shots, it would be the DA 16-85mm . It is not as compact as the 18-135mm lens. Both offer very good construction with WR.

[dms]

You don't mention what FL/FL range you seem to like, the Pentax pancake lens on film (I think you said you liked) would be the 40 mm FL, which is about 26 or 27 mm on K-3 (for same field of view). So if you want a zoom (I don't like zoom for outdoors hiking, but that is likely a minority view) I would suggest the 28-70mm FA f/4 lens. (I have mentioned this lens often, and I have two of them, which I use a lot at f/5.6.) It is incredibly low in price (~$ 40 used), and optically very good, and light weight, and AF seems to work fine. Build quality is not great, but it works OK. It has aperture ring and a distance scale--the latter is very important IMO.