Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
next PZ lens test report: Pentax DA 18-135mm f/3.5-5.6 WR
#1
Avoid ...



[url="http://www.opticallimits.com/pentax/597-pentax_18135_3556"]http://www.opticallimits.com/pentax/597-pentax_18135_3556[/url]
#2
[quote name='Klaus' timestamp='1302954835' post='7677']

Avoid ...



[url="http://www.opticallimits.com/pentax/597-pentax_18135_3556"]http://www.opticallimits.com/pentax/597-pentax_18135_3556[/url]

[/quote]



A couple of comments:



Optical Rating: The DA18-135 is an optical doppelganger of the [url="http://www.opticallimits.com/canon-eos/462-canon_18135_3556is?start=1"]Canon EF-S 18-135mm[/url], but the latter gets an extra +0.5 stars.



Not to mention the Canon benefits slightly from a smaller sensor size.



Further, the DA 18-135 is pretty tiny at 73mm length while the EF-S is 101mm, so the optical rating should be tempered a bit by the size...some concession can be made to trade-off for portability.



Price/Performance Rating: The DA 18-135 is only USD49 more than the EF-S 18-135 (according to the B&H ad beside the ratings), but the DA 18-135 includes the 2-pc hood (retail $60 value, FWIW), weather seals and metal body. Yet the Canon gets +1.5 stars. Sorry that the Europeans are getting shafted on the pricing, but the Price/Performance rating would be more fair with regional conditions (although they were mentioned at the beginning of the article, anyone jumping to the rating/conclusion would not get that).



That said, it's still only a mediocre lens, but the rating and "Avoid!" warning seem a bit harsh.



Also, I wonder how much the K-5 body will show up lens uneveness. As noted in the Canon review "...it's really surprising to see that this lens is bundled with the EOS 7D which is even more demanding in terms of required lens quality than the EOS 50D used for this test.".
#3
Hi Dave,



the Canon 18-135mm is available for 340$ (whitebox) and B&H. The Pentax goes for 500$ there. So the pricing difference is not just a European thing.

The Pentax lens has a rather massive field curvature issue at 18mm (as mentioned in the review). The charts look much better than the actual quality at this setting.

The Canon is the better lens of the two. And both are beaten by the corresponding Nikkor.



I think the rating is valid as well as fair.



Klaus





[quote name='dave9t5' timestamp='1302966962' post='7679']

A couple of comments:



Optical Rating: The DA18-135 is an optical doppelganger of the [url="http://www.opticallimits.com/canon-eos/462-canon_18135_3556is?start=1"]Canon EF-S 18-135mm[/url], but the latter gets an extra +0.5 stars.



Not to mention the Canon benefits slightly from a smaller sensor size.



Further, the DA 18-135 is pretty tiny at 73mm length while the EF-S is 101mm, so the optical rating should be tempered a bit by the size...some concession can be made to trade-off for portability.



Price/Performance Rating: The DA 18-135 is only USD49 more than the EF-S 18-135 (according to the B&H ad beside the ratings), but the DA 18-135 includes the 2-pc hood (retail $60 value, FWIW), weather seals and metal body. Yet the Canon gets +1.5 stars. Sorry that the Europeans are getting shafted on the pricing, but the Price/Performance rating would be more fair with regional conditions (although they were mentioned at the beginning of the article, anyone jumping to the rating/conclusion would not get that).



That said, it's still only a mediocre lens, but the rating and "Avoid!" warning seem a bit harsh.



Also, I wonder how much the K-5 body will show up lens uneveness. As noted in the Canon review "...it's really surprising to see that this lens is bundled with the EOS 7D which is even more demanding in terms of required lens quality than the EOS 50D used for this test.".

[/quote]
#4
[quote name='Klaus' timestamp='1302954835' post='7677']

Avoid ...



[url="http://www.opticallimits.com/pentax/597-pentax_18135_3556"]http://www.photozone...ntax_18135_3556[/url]

[/quote]



Hi Klaus,



Thanks for the work. Would have been nice to see some real world samples for the 135 setting (in particular architecture!). For the Pentax 50-200 you have some samples which show that the criticism you work out in formal testing is significant for real world shooting. While I trust you that this is the case here as well, it is always nice to see it with your own eyes <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='Smile' />



Have a good sunday.

Joachim
enjoy
#5
Klaus,



Thanks for the review. It is interesting that the DA 18-135 has received praise elsewhere. My guess is that typically people only look at a large middle section of photos to evaluate sharpness, which may explain why your review contrasts with user's perceptions. Users have complained that it is soft at the long end, so the extreme corner sharpness aligns there. I understand the field curvature issue and the impact that this can have too on the edges. Regarding contrast would you say it is lower, higher or average? Contrast also impacts photo quality perception. For example, on the Sigma 18-125mm review you mentioned lower global contrast than average. There is also Bokeh, but my guess the other factors are more important on such a lens.



Thanks
#6
[quote name='walbert' timestamp='1302982800' post='7684']

Klaus,



Thanks for the review. It is interesting that the DA 18-135 has received praise elsewhere. My guess is that typically people only look at a large middle section of photos to evaluate sharpness, which may explain why your review contrasts with user's perceptions. Users have complained that it is soft at the long end, so the extreme corner sharpness aligns there. I understand the field curvature issue and the impact that this can have too on the edges. Regarding contrast would you say it is lower, higher or average? Contrast also impacts photo quality perception. For example, on the Sigma 18-125mm review you mentioned lower global contrast than average. There is also Bokeh, but my guess the other factors are more important on such a lens.



Thanks

[/quote]



Well, the samples look quite snappy to me ... except for the borders ... so the contrast level seems fine in relation to the fact that it is a 7.5x zoom lens.
#7
[quote name='Klaus' timestamp='1302984054' post='7685']

Well, the samples look quite snappy to me ... except for the borders ... so the contrast level seems fine in relation to the fact that it is a 7.5x zoom lens.

[/quote]

Interesting. Thanks Klaus! Maybe it is the good contrast with good center sharpness that generates the positive user experiences. I guess you can make the lens perform decently if stopped down especially with the good contrast. I will stick with my DA 17-70.
#8
Thanks for the review, Klaus.



Ugh, the results are even worse than I expected!!

As others said, I guess the reason this lens gets somewhat good praises is because of the very good sharpness at all apertures/focal lengths combined with a good contrast.

However, the borders are pretty much the worst of any lenses you have tested!



I wonder what Pentax is doing? Do they suck so bad now at lens design?

They would be better off hiring some of Tamron engineers <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/wink.gif' class='bbc_emoticon' alt='Wink' />
--Florent

Flickr gallery
#9
[quote name='Klaus' timestamp='1302954835' post='7677']

Avoid ...



[url="http://www.opticallimits.com/pentax/597-pentax_18135_3556"]http://www.opticallimits.com/pentax/597-pentax_18135_3556[/url]

[/quote]





Hi Klaus



The edge performance of the sample on the pentax web site test of the 18-135 seems better compared to the 18-55 @18. Also the comparison to the DA* at 135 is better than your test result would indicate.



You can pull up the comparison of the two here:



http://www.pentaxforums.com/reviews/pent...w.php#comp



While this is not a quantified comparison, it is a good visual comparison of the performance. Perhaps sample variation is the root cause?
#10
[quote name='yesman`' timestamp='1303212906' post='7760']

Hi Klaus



The edge performance of the sample on the pentax web site test of the 18-135 seems better compared to the 18-55 @18. Also the comparison to the DA* at 135 is better than your test result would indicate.



You can pull up the comparison of the two here:



[url="http://www.pentaxforums.com/reviews/pentax_18-135mm_review.php#comp"]http://www.pentaxfor...review.php#comp[/url]



While this is not a quantified comparison, it is a good visual comparison of the performance. Perhaps sample variation is the root cause?

[/quote]



Maybe I don't get it but what exactly does this sharpness test tell us ?

I'm seeing a -------> square shaped <----------- Siemens star there. Consequently it ignores / masks all border and corner aspects. Our review already indicates that the center performance is no problem at all. We're criticizing the border/corners as well as the high field curvature at 18mm.



And again - our tested sample has been checked by Pentax. The posted sample images at the extreme ends look simply bad to me in the border/corner region.



Klaus
  


Forum Jump:


Users browsing this thread:
1 Guest(s)