As we all know, this lens received rather poor rating and adverse comments at the PhotoZone and then the official early samples posted by Ned Bunnell did look bad either.
But then stupid fanboys of Pentax like me are actually irrational ;->, I went bought this lens regardless of the poor reputation of this lens all over the Internet! :-o
This time, I am going to write a practical review on the lens, with more real-life photos of mine shown, for what this lens can deliver, on a K-5. You will see how "poor" this lens could be!~
First of all, still some comments of mine in words. As you can see from the above modelling photo, this lens is really compact and lightweight. It has an internal focusing mechanism such that the length of the lens will not change during focusing. And of course, the front element will not rotate.
I am much impressed with the build quality of this lens, which is the best amongst all DA Pentax standard zoom lenses that I have ever used, I would say. Even the bundled lens hood is better built than most of other Pentax', with matted lining inside and the rugged texture outside which contributes to a solid feeling. At the beginning, maybe owing to the weather sealing, when the lens was first opened brand new out of the box, it is very tight to zoom. But then after the first few days of use, the friction and resistance became just right provided that it is not zoomed too fast and too quickly otherwise higher resistance can still be found.
Speaking of the DC motor and its AF performance on K-5, it is fast, moderately accurate and silent although it is not completely silent and some very small sound can still be heard in really silent environments (ditto for the new Canon STM, which I also have). Under the Live View mode and with this DC lens, the LV CDAF is obviously faster than with other conventional type Pentax AF lenses.
Now, let's come to the IQ part, this lens is quite sharp in the image centre throughout the whole zoom range and from wide-opened, here are some various samples (Click to download in Large size, EXIF preserved):-
(18mm, f/3.5)
(18mm, f/5.6)
(18mm, f/6.7)
(21mm, f/4)
(21mm, f/8)
(28mm, f/4)
(36mm, f/4.5)
(36mm, f/6.7)
(36mm, f/8)
(40mm, f/7.1)
(53mm, f/6.3)
(100 mm, f/5.6)
(135mm, f/5.6)
It can be noted that the extreme corner softness is only existent at the widest side at 18mm. From 21mm and onwards, the effect is considerably eliminated and is not that noticeable. Distortion is significantly decreased, too.
In general, images produced are with good colours and contrast. Resolution is high throughout the frame except at the extreme focal ends, i.e., 18mm and 135mm. I do note that my lens' optics are perfectly centred by judging from the vignetting pattern, nevertheless. Maybe I am just lucky enough.
The flare resistance is superb. Look at this:-
The bokeh of this lens is not bad, look at these two (and also some of the above samples with a blurred background):-
Round bokeh of highlights can be seen.
Btw, why to use Live View with a DSLR? (I can see many DSLR beginners have been doing this!) Why not just use a K-01 if so?! :-o
There is one minor problem of this lens (or maybe the Pentax DSLR system in general), it is that it has a slight underexposure tendency, a +0.3/0.5 exposure compensation would usually cure it.
Besides, the Pentax SR system for tele-lens is proven to be ineffective, once again. I have got quite some blurred photos when shot at 135mm, just because the lens speed is slow but SR didn't help:-
All in all, I am quite satisfied with my copy of the DA18-135. It seems that my lens has far better performance than what is shown in the various measurbation tests and I do believe that it is a lens that performs well in real world but not so for measurbations. This maybe owing to the inconsistency quality control (or lenses are actually classified into different quality classes and batches - mine was purchased separately). The other possibility is that the optical design of this lens is not optimised for close range objects, where a test chart is placed and shot.
At the end of the day, this travelling zoom will not give you stellar optic quality which primes could give which is well expected, After all, let's see if my "favourable" review this time could retrieve the confidence of some potential buyers of this lens and maybe also for Pentax the brand as well! ;-D
Related:-
Interview with the Optical Engineer/Designer of the DA 18-135 Lens
Logging you in...
Guest · 657 weeks ago
Jazjohal · 657 weeks ago
RiceHigh 110p · 657 weeks ago
John · 657 weeks ago
But from the price perspective as well as from the weight/encumbrance you might have expected more.
Quality wise the Pentax 18-250 might even offer more, plus an extended range.
Bob · 657 weeks ago
dave9t5 · 657 weeks ago
I also bought this lens (despite PF's -ve review) after seeing users samples on the Pentax Forums. The sharp, contrasty, colourful character of this lens was obvious from those real-life images.
Although I have great respect for Klaus and PF, there are a number of flaws with their testing procedures and interpretations. A person really has to read between the lines on their results. For one, they never properly establish a base-line on a given system so their standards are always shifting. For another, they started off years ago testing (usually higher-end) full-frame optics on APS-C bodies so they got a false sense of what was "good". An average full-frame optic on film often had relatively soft to weak corners but were still "acceptable" on film. But since they started off testing those better FF optics on APS-C, they mostly tested very good on the cropped format. This became one of PF's false baselines. Another problem is that their "border "resolution point is so far to the corner that it's irrlevant in real-life. I've never had a subject in a photo where they place their border point. Their "extreme" point is even more ridiculous (it was only added because they could not otherwise get any useful separation between full-frame optics on APS-C). But between the center and border points (such as the rule-of-thirds point), there is zero data recorded. Just a big gap in the data. So, if the border result on PF's test is poor, you don't know if it's really poor across much of the frame or if it's sharp across the frame but then drops off very close to the corners (as many MTF curves show). So usually, only pay attention to PF's center resolution results.
So looking at PF's DA 18-135 test, it was easy to see that the center resolution was Excellent. This indicated to me that it would still be quite high across most of the frame that I care about. It was also easy to see that both the center and corners were usually better than the DA 18-55x lens tests, which are actually a pretty good series of zoom lenses. The other knock against the DA 18-135 was it's price, but Klaus was comparing it to CanonNikon models which were much larger, much more plastic and didn't include hoods.
In practice, my DA18-135 has been pretty good. My only compaint is that it back-focuses at wide-angle at middle distances. My DA14/2.8 had the same problem. I believe its because the focus throw on these lenses from around 2~3m to infinity is so very very short that the AF system just cannot resolve the focus movement small enough. Thus, alot of images of subject at 3m is focussed to infinity.
ricoh.pentax · 657 weeks ago
gonna wait for 50mm 1.8 review from you.
Richard · 657 weeks ago
Philip · 657 weeks ago
RiceHigh 110p · 656 weeks ago
Raffwal · 656 weeks ago
But perhaps after all I should give it a try...
jaco K-x · 656 weeks ago
Michael · 632 weeks ago
weddings & PR photography. I your opinions which would you better recommend?
RiceHigh 110p · 632 weeks ago
Simon T · 619 weeks ago
I do take lens reviews with some caution samples do vary no question, and yes some testers might have suspect methods too. In this range you expect compromises such as distortion and nobody expects tack sharp 100% across the frame wide open at all focal lengths. But you would expect pretty sharp images on most of the frame without stopping down loads. And here the Pentax is poor.
Straight off the bat 18mm is 18-55mm quality which is ok but not really that good (the 18-55mm is a weak kit lens IMO) You get some quite massive levels of CA and PF which is well beyond acceptable by anyone's standard, and tele end it's pretty bad not just extreme corners but outside the central area (which isn't even that sharp anyway) so welcome to stop it down loads time.
If anyone doubts the mediocre optics of the Pentax 18-135mm have a look here and you can see many samples at big sizes for yourself, including a few pages in the PF graveyard which shows a ridiculous level of PF issues.
http://www.pixel-peeper.com/lenses/?lens=13182&am...
IMO having used all of these lenses from Pentax, Canon, Nikon and Sony..the Pentax is by far the weakest lens out of it's 3 rivals. I agree a lens is more than sharpness and that we "want to love" a lens like this for it's convenience and useful range (and will accept some compromises too). Reality is if Pentax did a MkII 18-135mm and sorted out most of the obvious issues, ebay would be flooded with copies of the mark I it's just not as good as it should be.
Padmakar Srivastava · 501 weeks ago