[audiobomber]

Photozone value system does no justice to this lens. It just does not place a weightage/value on size/portability, light weight, silent/ fast AF, very close focus, rounded aperture for bokeh and WR in real usage situations.

Completely agree, PZ evaluations lack soul. Just the numbers please! Colour and contrast are rarely mentioned. Klaus and Pentax seem to have differing views on what's important in photography. This isn't the first Pentax lens to be panned on PZ.

I've only had the 18-135 for a couple of days and haven't given it a real workout. I took a couple of shots in freezing rain yesterday, which I think is worth mentioning.
So far I like it a lot better than the 18-250 that I handed off to my wife. Mechanically, it is a dream (AF, WR, no creep, solid build). PF is better controlled than the older superzoom, flare and distortion are lower. IOW, the things that bothered me most about the 18-250 are improved.

One of the main uses I intended for the 18-250 was event photography with camera bracket, cord, flash and zoom lens. The range was great, but the thing couldn't focus worth a damn in dim light. Even with AF assist, it was literally unusable. I tried the 18-135 for a few minutes and it locked instantly, every time. Zt-Zt, done.

I can still return the 18-135, but so far I don't see why I should, the photos look good enough. If I want better quality, I have other lenses. Nevertheless, I will test vs the 18-250 to see what I find.

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Last edited by audiobomber; 04-17-2011 at 07:27 AM.

[GeneV]

Well, I'll show my low standards by answering Falk's question about printing that snowy landscape: Yes, I would print it at A4, and 99% of the people who saw it would say "fantastic," because they don't care about the sharpness of the snow in the corners. They care about the sharp center and the gorgeous color and contrast. That does not mean that this or any other superzoom would be my lens of choice anyway for a poster-sized print of a landscape.

There is something strange going on with that photo anyway. Again, I may be showing my ignorance (and there is much to show) but why are all of the foreground highlights in the snow slightly elongated and pointing toward the center of the photo? When viewed at higher magnification, it almost looks as though the lens zoomed ever so slightly while exposing.

I think it would be a great point of reference if Photozone would retest the ubiquitous 18-55 using the K5 and whatever methods are in use today. A full review is not necessary, but just a comparison of resolution.

[hyyz]

Klaus and Pentax seem to have differing views on what's important in photography.

Totally agree. PZ makes a big deal of corner/extreme resolutions (even for F1.4 lenses like 85mm/1.4, etc.). What's more important, pleasing to your eyes or pleasing in testing chart?

[dasuhu]

I don't know why everyone is castigating Klaus so much. I don't believe very many people base their lens buying decisions exclusively on the cold, hard numbers on photozone. People who appreciate the MTF numbers are probably not parviscient about the other factors that make a good lens; hence they will also read about user experiences with the lens for factors that are not easily quantified.

The stars are arbitrary and capricious on that site, just like the user review point rankings on this site. I appreciate what Klaus is attempting to do, provide an objective benchmark on some of the many characteristics that define a lens. People usually balance those factors with what average users are saying and the photos they post of real-world applications. Somewhere between the cold numbers and opinions of owners of the lens likely lies the truth.

[Spotmatic]

Totally agree on this.
Super zooms are there for the purpose of convenience, versatility in one package.
The 18-135mm brings with it small size, light weight, silent and fast AF, very close focus and WR. If they were all round perfect, no one would be using primes.

Having used it. I'd not bat an eye lid recommending it to someone who wants this as a walkabout/travel lens.



Photozone value system does no justice to this lens. It just does not place a weightage/value on size/portability, light weight, silent/ fast AF, very close focus, rounded aperture for bokeh and WR in real usage situations.

+1 The lens tested may have been a poor sample. The only test that matters is yours. I never buy any new lens w/o a return option.

[falconeye]

Well, I'll show my low standards by answering Falk's question about printing that snowy landscape: Yes, I would print it at A4, and 99% of the people who saw it would say "fantastic," because they don't care about the sharpness of the snow in the corners. They care about the sharp center and the gorgeous color and contrast. That does not mean that this or any other superzoom would be my lens of choice anyway for a poster-sized print of a landscape

I agree that the center and colors are fine. Depending on the subject, that may be good enough to print indeed. For a landscape, I'd still say it is critical though.

There is something strange going on with that photo anyway. Again, I may be showing my ignorance (and there is much to show) but why are all of the foreground highlights in the snow slightly elongated and pointing toward the center of the photo? When viewed at higher magnification, it almost looks as though the lens zoomed ever so slightly while exposing.

The "like he zoomed" effect is due to the difference in meridonial and sagittal resolution for this lens (you may want to read about here or google the terms). While the sagittal resolution is as good as it gets for a lens of this class, the meridonial resolution sucks. The "startrail"-looking trail from a reflection dot in the snow is 12px long.

This means that the meridonial corner resolution for this lens is only 3264/12 or 270 LW/PH. A blur average with the (good) sagittal resolution yields less than 400 LW/PH, much worse than the published figure of 2000 LW/PH at this focal length and f-stop.

Klaus doesn't capture the full extend of the low resolution because he uses edge blur where boxes are NOT oriented sagittally/meridonially (like they should). He then sees 1/SQRT(2) of the better resolution which is a far too optimistic measure.

Any lens with a meridonial corner resolution at f/8 of only 270 LW/PH should be either verified be defect or be withdrawn from the market. This is what Klaus is in the process of talking about with Pentax.

I think it would be a great point of reference if Photozone would retest the ubiquitous 18-55 using the K5 and whatever methods are in use today. A full review is not necessary, but just a comparison of resolution.

I agree that Klaus needs a common point of reference.

But the best performing lens is the best possible common point of reference then, i.e., the FA 31 Ltd.

[GeneV]

I agree that the center and colors are fine. Depending on the subject, that may be good enough to print indeed. For a landscape, I'd still say it is critical though.


The "like he zoomed" effect is due to the difference in meridonial and sagittal resolution for this lens (you may want to read about here or google the terms). While the sagittal resolution is as good as it gets for a lens of this class, the meridonial resolution sucks. The "startrail"-looking trail from a reflection dot in the snow is 12px long.

This means that the meridonial corner resolution for this lens is only 3264/12 or 270 LW/PH. A blur average with the (good) sagittal resolution yields 485 LW/PH, much worse than the published figure of 2000 LW/PH at this focal length and f-stop.

Klaus doesn't capture the full extend of the low resolution because he uses edge blur where boxes are NOT oriented sagittally/meridonially (like they should). He then sees 1/SQRT(2) of the better resolution which is a far too optimistic measure.

Any lens with a meridonial corner resolution at f/8 of only 270 LW/PH should be either verified be defect or be withdrawn from the market. This is what Klaus is in the process of talking about with Pentax.

I agree that Klaus needs a common point of reference.

But the best performing lens is the best possible common point of reference then, i.e., the FA 31 Ltd.

Thanks for some excellent information. Perhaps I have been fortunate in my lens choices, but I have been making prints and looking at them for 40 years and had not seen astigmatism produce quite that effect, with clearly defined but elongated highlights. I am not an engineer, and I may not be looking at the right subject, but it usually appears to me to look like the light radiating from a star. It is not desirable in any case.

On the point of reference, perhaps the FA31 should be included as well because of its excellent performance, but for most of the users of a review, the most frequently owned lens, i.e. the kit lens, would be most useful. This would allow users to compare theory to experience, with something in their own bag. The FA31 is just too expensive for many enthusiasts who might read this review.

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Last edited by GeneV; 04-18-2011 at 06:38 AM.

[GeneV]

I don't know why everyone is castigating Klaus so much. I don't believe very many people base their lens buying decisions exclusively on the cold, hard numbers on photozone. People who appreciate the MTF numbers are probably not parviscient about the other factors that make a good lens; hence they will also read about user experiences with the lens for factors that are not easily quantified.

The stars are arbitrary and capricious on that site, just like the user review point rankings on this site. I appreciate what Klaus is attempting to do, provide an objective benchmark on some of the many characteristics that define a lens. People usually balance those factors with what average users are saying and the photos they post of real-world applications. Somewhere between the cold numbers and opinions of owners of the lens likely lies the truth.

Funny, but I don't really read people castigating Klaus. I think they are just saying that corner resolution is not everything. Everyone's mileage may vary.

[audiobomber]

Funny, but I don't really read people castigating Klaus. I think they are just saying that corner resolution is not everything. Everyone's mileage may vary.

Klaus has been fairly critical of several Pentax lenses that some shooters love, therefore they disagree with his evaluations. I believe it's because he has different expectations than many Pentax shooters. I see similar arguments in audio, where objectivists and subjectivists frequently clash over measurements vs listening. I like the look of 18-135 photos and I love the mechanics and operation of the lens. Some wouldn't touch it with a barge pole, oh well, that's life.

[GeneV]

Klaus has been fairly critical of several Pentax lenses that some shooters love, therefore they disagree with his evaluations. I believe it's because he has different expectations than many Pentax shooters. I see similar arguments in audio, where objectivists and subjectivists frequently clash over measurements vs listening. I like the look of 18-135 photos and I love the mechanics and operation of the lens. Some wouldn't touch it with a barge pole, oh well, that's life.

As a long-time tube fan, I get what you are saying.

[Ivor K Ecks]

I simply cannot agree with Klaus's evaluation of this lens
It is certainly better than the 18-55 kits lens and he gave that 2.5 stars.
There are certainly very few lenses that have a silent motor drive and WR that are cheap, in fact most of them are expensive.

Some sample shots from this lens that should be avoided.





And for those who want a full size image

http://PDIphotos.zenfolio.com/img/s3/v26/p447878257.jpg

[GeneV]

Ivor, just so we know how to evaluate the resolution numbers and the images together, would you mind letting us know the focal length and aperture information for those excellent images?

[Winder]

I think part of the problem is Pentax QC. It is entirely possible that some people have really excellent copies of this lens and that others have really bad copies.

I tried 2 copies of the DA*55mm before going with the Sigma 50mm f/1.4.

[Aristophanes]

On the point of reference, perhaps the FA31 should be included as well because of its excellent performance, but for most of the users of a review, the most frequently owned lens, i.e. the kit lens, would be most useful. This would allow users to compare theory to experience, with something in their own bag. The FA31 is just too expensive for many enthusiasts who might read this review.

The point of reference maybe should be Nikon's 18-135.

The Nikon has been around awhile so is a "settled" design, but it, too, has similar flaws, although the Pentax PZ test is clearly way off norms by a long shot.

Nikkor DX kit lens group test: 18-55mm vs 18-70mm vs 18-135mm vs 18-200mm VR Cameralabs verdict

18-135mm AF-S DX Lens Review by Thom Hogan

Clearly as a "long kit zoom" the 18-135 is a compromised design from any manufacturer as were the 28-200's they replicate for 35mm.

We are probably not arguing the merits of the 18-135 design itself which is obviously challenging, but why the Pentax version is so off the rails from the single PZ test.

[GeneV]

The point of reference maybe should be Nikon's 18-135.

The Nikon has been around awhile so is a "settled" design, but it, too, has similar flaws, although the Pentax PZ test is clearly way off norms by a long shot.

Nikkor DX kit lens group test: 18-55mm vs 18-70mm vs 18-135mm vs 18-200mm VR Cameralabs verdict

18-135mm AF-S DX Lens Review by Thom Hogan

Clearly as a "long kit zoom" the 18-135 is a compromised design from any manufacturer as were the 28-200's they replicate for 35mm.

We are probably not arguing the merits of the 18-135 design itself which is obviously challenging, but why the Pentax version is so off the rails from the single PZ test.

Maybe, but it is not a point of reference for most Pentax users to use in comparing resolution figures from one Pentax lens that one owns (tested on a K10) to another that has been recently tested on a K5.