[UncleVanya]

The 18-135 is a better lens than it reviews as. There’s an entire thread (currently 247 pages) devoted to images made with it:
DA 18-135 WR, Show us what it can do - PentaxForums.com

The optical limits review shows the details on resolution. Bear in mind these results aren’t on the most modern sensor but you would expect the text to be the same. At wide angle, stopping down is very effective at improving corners:
Pentax SMC-DA 18-135mm f/3.5-5.6 ED AL [IF] WR - Review / Lens Test

I’ve used mine on the K-3 and K-50 primarily. It’s been a real winner. At 20-24mm it is very nice indeed. At 70-85 it makes great portraits with the right background. At 135 you can get shots that the 16-85 can only get by cropping.

Speaking of cropping, the comparison in the da 16-85 review they compared the 85 cropped to the 135 end of the 18-135 and the results may surprise you:
Pentax 16-85mm First Impressions Review - Hands-On Tests | PentaxForums.com

My KP arrives today. I plan to use it both with my 18-135 and 20-40 lenses at various times. If I was in your shoes the two lenses I’d consider for hiking would be the 16-85 and 18-135. Of these I’m pretty sure I’d go with the 18-135. It is lighter, cheaper, and longer. The extra wide 16-85 is not a bad alternative however. It’s a bit heavier but offers wide angle shots to rival the more expensive 16-50 f2.8. Here’s the optical limits report on it. You can see it’s more even at the long end, but at 85 the 18-135 has only just started to wane on the outer edges:
Pentax HD DA 16-85mm f/3.5-5.6 ED DC WR - Review / Test Report - Analysis

[jgnfld]

My standard hiking/boating kit is a 16-85 and a 55-300PLM using a KP (also have a K-70 body). I own a 17-50 f2.8 Sigma, but I just cannot warm to how my copy renders landscapes here. I use it for special situations indoors and about town/docks esp. at night where the extra f-stops are helpful. (Plus it really does rain a lot here!) OTOH, my copy of the 16-85 just plain renders my landscape scenes beautifully. One issue with the 16-85 (as well as the 55-300PLM) where I shoot is that Newfoundland is often a very dark environment even during daylight hours what with thick cloud layers and, for much of the year, a low sun angle even at noon. Plus much of the terrain is under dense forest cover. With a KP, this is simply not a problem, however. In fact having a KP is one of the reasons to rely so heavily on this pair of lenses. They really work with each other well. In this regard, my old K-50 (now gone to a friend along with kit lens and an old screw drive SMC 50-300) could get pushed severely by having to use high ISO many days.

I also often put my 40mm Ltd. in a small sock and carry it in a pocket. Adds no weight, really, and my copy really does render golden hour scenes beautifully.

Last but not least, if I think there will be macro shots, I do carry a 100mm WR macro, but in such cases we are talking of more dedicated photo expeditions, not hiking/sailing with a camera along.

Have some other lenses--the DA70 is a new acquisition I am starting to really like--but none in general, everyday use.

[JensE]

Last but not least, if I think there will be macro shots, I do carry a 100mm WR macro, but in such cases we are talking of more dedicated photo expeditions, not hiking/sailing with a camera along.

The 55-300mm PLM is part of my "extended hiking/kayaking" kit, together with a matching 3DPT marumi achromat, it's really an adequate substitute for a dedicated macro lens.

[ramseybuckeye]

I have a KP, I had A Sigma 17-50 and DA 18-135, I bought the Sigma for when I needed a faster lens. A year and a half ago we were planning a trip to London in October. I decided that I wanted a faster lens that was also weather sealed, so I ended up buying a DA20-40. It was great since there were overcast and rainy days and also some night walks. Anyway I loved the 20-40 so much I never used the 17-50 again, so I sold it. The 20-40 is so much better I really don't miss the 17-19 and 41-50 range. I still have the 18-135 and although I don't use it as much as I used to, it not a bad lens for landscapes or general purpose, the 20-40 and 55-300 PLM are both better in my opinion. I've read that the 16-85 is quite good too. The 20-40 and 55-300 PLM are usually with me, unless I go with one lens, then it is either of those two or the DA*300, depending on where I am walking. The 20-40 feels and looks like it was designed for the KP.

[timb64]

I am very happy with my two lens kit of 16-85 and 55-300 PLM on my KP,WR,covering a wide range of FL and good IQ.

[gatorguy]

I am very happy with my two lens kit of 16-85 and 55-300 PLM on my KP,WR,covering a wide range of FL and good IQ.

That makes a great landscape/field combo IMHO, and doesn't require a mortgage. Good choices.

[Ronald Oakes]

I am really pleased with my 16-85 and 55-300 PLM combo. It is hard to beat on a trip or when going on a hike, and it is great to know that they are both weather sealed. .

This is what I use with my KP and couldn't be happier !

[3by2]

The KP and the 20-40 look great together. It's also a light lens, a lot lighter than something like the 18-135, which I instantly didn't like. The 20-40 lives on my KP now, it's a camera well suited in design to the ltd's, however these are, as ever, all personal choices.

[DeadJohn]

The 16-85 and 18-135 are both good lenses. Decide whether the 16mm wide end or 135mm telephoto end is more important for your photography.


The 16-85 has better image quality of the 2 lenses, but the 18-135 is not bad. Don't fear the corner sharpness of the 18-135 for landscapes. You'll likely use f/8 or smaller to get good depth of field and the corners sharpen up nicely with those settings.

The 18-135 is lighter and smaller than the 16-85. Both lenses are IMO small enough for hiking.

[angerdan]

Anyway, I will need a replacement to the 18-50 and 18-250, with the following requirements :

• Focal length versatility : should be able to do wide angle and telephoto
• WR
• Light or at least not front-heavy would be good to have
• Silent focusing would be nice but definitely not needed
• Fast aperture is definitely not needed

Other suggestions?

HD D FA 28-105mm offers the best image quality besides the D FA 24-70mm. And it's more lightweight than the DA 16-85mm.
Weather Sealed Lenses | PentaxForums.com

By front-heavy, I mean that the camera has a tendency to tilt toward the ground when the strap is around my neck.

You could just switch to an shoulder strap. Great improvemet for handling and carrying as well.
BlackRapid Sport X Coyote Camera Sling - BLACKRAPID

[tibbitts]

I have the Sigma 17-50 and the Pentax 16-85. They're both very good when properly focused, although it was a struggle for me getting a half-decent copy of the 16-85 buying new. I bought a used 17-50 here and it's been fine. My 17-50 does have an annoying little looseness in MF that's about 1/10th as bad as the 16-85 jumpy focus (a feature on all the many copies I tried.) I do really enjoy the brighter image on the 17-50 and can use MF with it, but find MF impossible without live view on the dim 16-85. Both have some AF issues on all my bodies. I almost don't care with the 17-50 because I can use MF without live view. Also the 16-85 occasionally loses the ability to AF at all - it tries but won't lock. Eventually it gets going again, as soon the the picture opportunity vanishes (It seems to have a special sensor for that.) So if I was in a situation when I couldn't wait for the lens to decide how it was feeling about AF at any given moment (like one time on a boat tour), I'd go with the Sigma.

[UncleVanya]

HD D FA 28-105mm offers the best image quality besides the D FA 24-70mm. And it's more lightweight than the DA 16-85mm.
Weather Sealed Lenses | PentaxForums.com

However it has almost no wide angle on crop. Using this lens on crop is the same as using the FA 43 Limited on the K-1 as far as the maximum width...

28-105 on KP: APS-C: 53-15.5 ° / 46-13 °
FA 43 on K1: Full frame: 53 ° / 45 °

The OP asked specifically for wide angle:

It will be used when lens switching will not be possible (like hiking with family) and bad weather when wide angle might be desired. About kind of shots on a hike, I like to use wide angle and also telephoto shots, often on the same scene.

I don't think the 28-105 has anything wrong with it. It is a great lens on FF and a great option for a crop shooter who wants barely wide to modest tele with high IQ images.

[mikesbike]

I have found the silent AF of my DA 18-135mm has been reliably faster, more sure and accurate than that of most of my many other lenses, used with numerous camera bodies over the years. Another plus for this lens. The AF of my DA 20-40mm Ltd, which I've used almost exclusively on my KP, has been very good also, though perhaps not quite as quick as that of my DA 18-135mm.

[Bertrand3000]

Thank you all for your answer.

It looks like that if I really want a single lens for a trip, the 18-135 is the one who fits the most.

But we do not buy DSLR cameras to use a single lens on them. Many people mentioned the 16-85 to be paired with the 55-300 PLM I already have. It looks like a deadly combo.


I am a bit worried about quality issue mentioned here and also somewhere else on pentaxforums about some 16-85's, but perhaps it is not worse than with any other lens? Would buying an used 16-85 be mostly safe?

[angerdan]

Many people mentioned the 16-85 to be paired with the 55-300 PLM I already have. It looks like a deadly combo.

I'd bet on this!
HD Pentax-DA 16-85mm F3.5-5.6 Review - Conclusion | PentaxForums.com Reviews
Weather Sealed Zoom Lenses | PentaxForums.com