[pinholecam]

Frankly, I was not impressed when Pentax launched this lens in Oct2010.
I said to myself.
"18-135mm at f3.5-5.6? Bah! a glorified kit lens at a 'glorified' price.
Won't even touch one with a barge pole. "

Its been 6 months now, and many favorable comments/reviews/photos as well as briefly trying out the sample lens at the local service center made me accept it as a rather 'nice' zoom.

So it seemed that the Pentax Gods made jest of me when all of a sudden I found myself winning a mini local Pentax forum contest and was 'gifted' with the DA 18-135.
Since it was fated to try one out, I decided to make the best of it and write a review about the lens and share my experience with it.


Disclaimer : I have since sold the lens. This review comes after the sale as I did not want to be influencing demand in the local buy and sell marketplace with this review.
Why I sold it?
Read on....

[pinholecam]

SMC Pentax-DA 18-135mm F3.5-5.6 ED AL [IF] DC WR

Intro
======



The DA 18-135mm F3.5-5.6 DC WR is Pentax's answer to the walkabout zoom lens on the APS-C format sensor. The lens ranges from 18mm to cover wide views/landscapes to 135mm telephoto to cater for further subjects, portraits and close-up shots. It seemingly caters for the vast array of needs of the shooter who wants to rely primarily on a do-it-all lens. The focal length coverage is topped up by light weight, small size and weather sealing, all of which will come in useful on long treks, freaky weather on tour and dust/water/mud splash that can happen when shooting a motorbike/car X-country rally for example.


This lens uses the new DC autofocus motor which is touted to be faster and more silent than the previous SDM used by the older lenses like the DA*50-135/2.8.
It also features PENTAX Quick Shift focus system to allows instant on-the-fly switching from auto to manual focus.
Another nice icing on the cake is the 7 blade rounded aperture to help give a nice bokeh, not seen on lenses considered as 'commercial zooms'.


Specs
I won't go too much into the specs. These are everywhere on the internet via a web search. As such, I will just list the spec here for general reference only.

Straight from the Pentax site :
http://www.pentaximaging.com/product.aspx?id=smc%20PENTAX-DA%2018-135mm%20F3...=camera-lenses


* Optical Construction: 13 Elements in 11 Groups
* Diagonal Angle of View: 76-11.9 Degrees
* Maximum Aperture: F3.5-5.6
* Minimum Aperture: F22-38
* Aperture Blades: 7 (rounded)
* Mount Type: KAF3 Mount
* Minimum Focus Distance: 0.4m (1.31 ft)
* Maximum Magnification: 0.24x
* Filter Size: 62mm
* Lens Hood: PH-RBC62mm (included)
* Max Diameter x Length: 73mm x 76mm (2.9in x 3.0in)*
* Weight: 405g (14.3oz)
* Hood Weight: 24g (0.8oz)
* Optional Case: S80-120
* Hood Type: Bayonet
* Cap Type: Clip-On
* Image Circle: APS-C





Physical
The lens is nicely made. Barrel is plastic but feels quite sturdy, with a rubberised grip area on the zoom ring. The focus ring is placed before the zoom ring, which is a departure of the previous Pentax convention. It needs some getting used to, but to me it makes more sense for a rather small zoom as the user can continue to hold the camera near the body/lens area. I wish I had the 18-55mm kit or a Nikon 18-105 to photograph and better reference the size of this lens. Its certainly smaller than the latter. In fact its smaller than the Sony 18-135mm. What I can show is the 18-135 together with the A50/1.4 and Tamron 28-75/2.8



From left : A50/1.4; DA18-135/3.5-5.6; Tamron 28-75/2.8

As can be seen its a rather small lens for a zoom covering 18mm to 135mm. Just a bit bigger than say the 18-55mm kit if I had one to compare.



metal mount and rubberized seal

[pinholecam]

Performance

Now, the part that is interesting. How does this rather expensive zoom perform?

I wanted to see the real world performance of this lens. Its wide angle through to telephoto capability to 'support' a walk about.
Since I did not have much chance to go out to the local Grand Canyon, I took my favourite model downstairs telling the wife that I was buying bread from the local store.



18mm f3.5
wide open



18mm f3.5
wide open



18mm f5
Wide angle, close up capability while retaining very good OOF rendering with a bit of stopping down



53mm f4.5
wide open



53mm f5.6
Stopped down a little from wide open. Shallow DOF and nice OOF rendering with the very close focus capability (note the effect of the rounded aperture blades)



100mm f8
Long focal length of 100mm while stopping down to f8 for max sharpness and DOF plus close focusing capability. Background can easily be thrown out of focus!



135mm f5.6
Another demonstration of close up ability. 135mm and wide open at f5.6


What blew me away was the trick up its sleeve. The close focus of up to 40cm. That is even when it is at 135mm. A typical lens has a minimum focus roughly its focal length in cm. A typical 135mm would only focus to around 135cm. But with 40cm close focus, it provides the opportunity to get very close up for detail shots. Very useful in a walk about (smell the flowers, then photography them if you will). It also throws so much of the background out of focus to isolate the subject. Very 'macro lens like'.

[pinholecam]

I wanted to show off more of the lens, so I went for the local Start of Year (SOY) cosplay event held at Ngee Ann Polytechnic. It was also a chance for me to do some strobing/studio work.

The atmosphere was great. Friendly young folks who have put in lots of effort in their costumes.
For those unfamiliar with Cosplay, just think Comics/Sci-Fi Convention, only this time its for Japanese Manga(comics) and animation. Replace Superman with Ultraman and you get the idea.


40mm f8



100% crop straight JPEG unsharpened



18mm f7.1



100% crop straight JPEG unsharpened; To me this is damn good for all in one zoom at 18mm




18mm f8

---

Last edited by pinholecam; 04-12-2011 at 10:57 PM.

[pinholecam]

Here is a comparison of the close focus ability of the DA18-135mm at 135mm against a venerable K135/2.5. It seems to me that this is the best way to showcase the 'trick up its sleeve'



DA18-135 at 135mm f5.6, 40cm min focus distance



K135/2.5 at f2.5, 150cm min focus distance


The difference is significant.




Center sharpness
Now something more dry. Pixel peeping 100% crop for center sharpness. I'll be the first to admit that this is no rock solid test. I don't even have a test chart (nor will I bother to have one).
The setup is a simple table calendar, which of course is slightly slanted and may not be in perfect alignment to camera/sensor. One of the reasons why I won't do more than a center test.
I'm too lazy to do so many crops for the edges being my other reason.
Of course sharpening is set to '0' on the camera for this.


18mm


Original shot. I notice significant barrel distortion. Not sure if its real or because of the tilt of the calendar, though I suspect the former.




100% crop (center) 18mm f3.5



100% crop (center) 18mm f4



100% crop (center) 18mm f5.6



100% crop (center) 18mm f8

48mm
I was actually aiming for 50mm, but I guess 48mm is close enough....


48mm. Full shot. Notice that there is no more distortion




100% crop (center) 48mm f4.5




100% crop (center) 48mm f5.6




100% crop (center) 48mm f8

[pinholecam]

135mm



135mm. Full shot. Notice that there is no more distortion




100% crop (center) 135mm f5.6




100% crop (center) 135mm f8


Overall, sharpness is good on the lens even wide open. As with all lenses it gets better stopped down. To me what is important is that it is usable without a doubt at its largest aperture on all focal lengths.
If sharpening is applied to bring out the best for each shot, it will certainly be much better.

[pinholecam]

Final Thoughts
I guess everyone has their own conclusions for this lens at this point.
For me, I began as a bit of a skeptic, wanting to see what this lens was capable of. Happily, I must say, I'm very impressed.

The DA18-135mm is worth every cent of its price.
It is certainly NOT a commercial zoom, but a well made, well thought out and designed enthusiast lens.
It fits almost every criteria of a walk about lens. Small size; light weight; Weather sealing (esp. dust and water); focal length coverage that 'makes sense' on a tour/walk about; very close focusing, fast focus with the DC motor. One can always argue that 18-200mm is even more length, but to me I would not agree with the size, weight and seldom do I find 'dire need' at 200mm on a tour.
The other great feature is the close up ability, again on a tour, see the nice flowers, take a shot and run after the wife, no need to ask everyone to wait and change to a macro lens.
Those who can leave their missus and kid behind with that 200-500mm lens to hunt down that elusive Malayan Sea Eagle on a family tour can well disagree


The only point that it misses is aperture speed. Its a bit of a nit-pick, since this is a zoom. It would not be this price/size/weight if it was a fixed aperture lens. Couple this with a DA35/2.4 or Fa50/1.4 for low light and everything is solved.


Pentax knows its lens design and its a lens design philosophy that agrees with me a lot.
'Don't design them BIG if you can'
Ok.. I made this up... but Pentax do make them smaller
I can't emphasize enough of this. Compared to the equivalent offerings at 18-105mm and 18-135mm by other brands, the DA18-135 is smaller, which translates to being more portable and 'smarter by design' if you will.



Finally, why did I sell it if I like it?
I use mostly primes. I have an addiction to fast lenses. As such, I have three 135mm lenses and I already have trouble rotating use between them. Using a capable lens like the DA18-135mm, will also mean I reduce the use of my other primes within the focal length. The less I use those, the less 'return of investment' I get from my expensive primes. Top this up with the fact that each prime has its own fun factor, character and marvelous output, and the DA18-135mm has to go.

---

Last edited by pinholecam; 04-14-2011 at 10:10 PM.

[Adam]

Nice review! Wouldn't it fit better in there dedicated reviews section here: SMC Pentax-DA 18-135mm F3.5-5.6 ED AL [IF] DC WR Reviews - Pentax Lens Reviews & Pentax Lens Database ?

[pinholecam]

Nice review! Wouldn't it fit better in there dedicated reviews section here: SMC Pentax-DA 18-135mm F3.5-5.6 ED AL [IF] DC WR Reviews - Pentax Lens Reviews & Pentax Lens Database ?

Adam, Thanks.

I did not realize that my very long winded review would be able to fit the lens review page.
Do feel free to move it there if necessary.

[the swede]

Very nice review! I love this lens. I started this thread:

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/134615-pentax-...s-samples.html

[the swede]

Very nice review! I love this lens. I started this thread:

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/134615-pentax-...s-samples.html

Would love to see your pictures posted there!

[Spotmatic]

Nice review of a capable lens.

[kheldour]

Great review. I'm actually looking right now for a lens to replace my kit lens.
This one could be the one.

Again, thanks for the review.

[pinholecam]

Very nice review! I love this lens. I started this thread:

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/134615-pentax-...s-samples.html

Would love to see your pictures posted there!

Thanks. I'll put up some picture over there once I get a chance to sort through those I did not use in the review

Nice review of a capable lens.

Thanks. Yes, very nice lens indeed.

Great review. I'm actually looking right now for a lens to replace my kit lens.
This one could be the one.

Again, thanks for the review.

Hope the review helps you decide on the lens.





Review completed, BTW.

[pinholecam]

Some more sample images from the cosplay event