Pentax-DA 18-135mm F3.5-5.6 Review

Weather Sealing

There is no doubt that the mention of "Weather Resistance" or "Weather Sealing" is an exciting quality in any interchangeable lens, something that Pentax users have come to expect rather than hope for in new lens designs by their brand of choice. In the event you stopped counting, there are 13 lenses in the Pentax lineup--not including the 645D/Z medium format system--to offer weather sealing. Pentax has a storied tradition in the digital photography era of offering proven weather sealed lenses and cameras (and now two external hotshoe flashes).

Schematic showing the individual weather seals (in red) of the DA 18-135 WR
lens mounted on a Pentax K-3 and its optional (also weather sealed) D-BG5 Battery Grip.

Understandably, there has been confusion as to what "weather sealing" amounts to, as that's a pretty open-ended (and exciting) term. With Pentax, you'll know if something is ready to brave Mother Nature (as long as you are!) thanks to specific designations in the product's official name. Note that for Pentax's camera bodies, this information is merely stated in the specifications rather than the name. The following list identifies Pentax's different grades/levels/tiers of weather sealing found throughout its product line:

  • WR - "Weather Resistant" - protected from water ingress
  • AW - "All Weather" - protected from water and dust ingress
  • DA* - a specific line of premium grade lenses that incorporate AW level dust and water resistance

It is critical to note that none are rated as submersible (despite a few intrepid Pentaxians purposefully dunking their cameras in pools) when it comes to water ingress protection, but rather water spray, light and heavy rain, snow, shower heads, hoses, faucets etc.  Zooming, especially extremely quickly, with the lens while wet may increase the chance of water ingress.

In our experience, we have not witnessed much of a practical difference between WR and DA*/AW. Both levels have proven excellent guardians against both water and dust, although our confidence is surely with DA*/AW when the tiny particles become a true nuisance.

Rubber Gasket on the Lens Mount

The lens mount of all weather resistant lenses are equipped with a rubber o-ring that causes a seal once compressed upon mounting the lens to a camera body. The lens mount, or the big massive hole in your digital imager, is undoubtedly the most dangerous location for a camera/lens combination when it comes to unwanted infiltration by dust and water.

We wish every lens came equipped with a rubber gasket even if it weren't weather sealed to minimize the intrusion of dust particles, but that would most likely be problematic because uninformed users might mistake that for their lens being waterfall-ready.

Regardless, below is that such circular guardian (in red) on a DA 18-135 WR's lens mount:

DA 18-135 WR Weather Sealing Gallery

*For a much larger resolution animated .gif, click on the above image. For a Behind the Scenes (BTS) of the above, click here.

Below is a gallery of the images taken with the DA 18-135 WR during inclement conditions, collected across the Pentax Forums' userbase.

Click on any image to enlarge it for a better view.

Photo by: CristiC, K-30, 78mm, 1/200s, F9, ISO 200

Photo by: mattb123, K-3, 135mm, 1/125s, F13, ISO 400

Photo by: StephenHampshire, K-5, 83mm, 1/500s, F6.3, ISO 160

Photo by: Zorglub, K-5, 24mm, 1/160s, F8, ISO 250

Photo by: mattb123, K-3, 135mm, 1/200s, F10, ISO 400

Photo by: lister6520, K-30, 31mm, 1/60s, F4.5, ISO 200

Photo by: ausmoose, K-30, 53mm, 1/125s, F8, ISO 400

Photo by: JustinThomason, K-30, 88mm, 1/100s, F5.6, ISO 400

Photo by: Zorglub, K-5, 53mm, 1/160s, F8, ISO 125

Photo by: StephenHampshire, K-5, 68mm, 1/160s, F6.3, ISO 2000

Photo by: CristiC, K-30, 36mm, 1/200s, F7.1, ISO 200

Photo by: lister6520, K-30, 18mm, 1/100s, F3.5, ISO 400

Photo by: mattb123, K-3, 53mm, 1/400s, F14, ISO 400

Photo by: StephenHampshire, K-5, 36mm, 1/400s, F6.3, ISO 1000

Photo by: Weldon Berger, K-30, 18mm, 1/1000s, F7.1, ISO 100

Photo by: Clarkey, K-5 IIs, 135mm, 1/320s, F8, ISO 1600

Photo by: lister6520, K-30, 18mm, 1/200s, F5.6, ISO 3200

Photo by: sealonsf, K-5, 18mm, 1/80s, F4.5, ISO 200


The weather sealing on the 18-135 is no gimmick or some mere marketing ploy. It works. The animated .gif above was one of the first things we did with the lens upon starting this review, and since then it hasn't so much as hiccuped for the rest of the testing we've done.

None of the above images will win any awards for sharpness or clarity. But more important than what is technically capable (don't you fret, we'll get to scrutinize and discuss a myriad of comparison tests and sample photos in the following pages), the above images demonstrate new opportunities afforded by a weather sealed camera-lens combination that otherwise would have been missed thanks to leaving your camera at home or in the bag.

Along the same vein, take a look at this image, taken with a K-3/HD 55-300 WR and from the weather sealing section of our in-depth review for that lens:

For those that haven't already seen that image - notice anything? Click here to take a closer look.

With the DA 18-135 WR, Pentax has given us yet another way to not be her.

On the next page we take a look at the built-in autofocus motor and how well she spins. PentaxForums +Pentax Forums @PentaxForums News | Reviews | Forum

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