DA 18-135 on photozone

dgaies · 04-21-2011, 05:08 AM

Originally posted by Spotmatic

Maybe the PZ review will cause the price to drop?

It's quite possible

I got my 18-135 pretty cheap (around $300 when all was said and done), so as I've said in previous posts, perhaps my expectations are lower as a result.

frogfoot · 04-21-2011, 05:32 AM

Originally posted by Rondec

Right here: https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/140953-superzo...ml#post1472037.

Thanks... Hm.. It looks like his 18-135 is sharper at 135 mm than 18-250...
As for me I found my 18-135 quite unusable at 100 mm and above...

audiobomber · 04-21-2011, 06:16 AM

Originally posted by frogfoot

Thanks... Hm.. It looks like his 18-135 is sharper at 135 mm than 18-250...
As for me I found my 18-135 quite unusable at 100 mm and above...

One has to wonder if this is a Pentax quality control issue.

yusuf · 04-21-2011, 06:57 AM

I was never enthusiast about this lens. They should have tested at same resolution to compare MTF against other lenses.

deadwolfbones · 04-21-2011, 07:13 AM

Originally posted by yusuf

I was never enthusiast about this lens. They should have tested at same resolution to compare MTF against other lenses.

You don't think every company does this for every lens they make?

GeneV · 04-21-2011, 07:40 AM

Originally posted by audiobomber

One has to wonder if this is a Pentax quality control issue.

QC is quite possibly an issue, but different people have different definitions of "unusable" as well. I've heard people call the kit lens unusable, and I find it quite handy in many situations.

Menno · 04-21-2011, 08:36 AM

Originally posted by audiobomber

My 18-135 has better sharpness than my 18-250 in the center and across the frame, at 18mm and 135mm. I only tested wide open because the gap disappears as the apertures close.

https://picasaweb.google.com/bonhommed/18135Vs18250#

I haven't tried 18mm against a brick wall but in landscape test-shots the borders with my 18-135 at 18mm f3.5 were much softer than I see on your samples. The field curvature thing could explain that it's not to the same degree in every scene.

Originally posted by audiobomber

I'll believe a 50-200 is sharper when I see it confirmed. Sharpness is not comparable on the PZ tests due to different bodies, and I strongly suspect the lens used was substandard (not Klaus' fault).

Above 75mm my DA50-200 performs better in every way than my 18-135 except for autofocus. But it all depends on what copy you get I suppose.
I've posted a 100% crop here on the other forum:
big 100% crop: Pentax SLR Talk Forum: Digital Photography Review

Eruditass · 04-21-2011, 09:14 AM

Originally posted by audiobomber

One has to wonder if this is a Pentax quality control issue.

I think with consumer lenses, quality varies pretty widely, often greater than average performance between different lens models, with the minimum bar set rather low. Stellar performers are often not really supposed to be stellar, luck just granted them a good one.

yusuf · 04-21-2011, 09:15 AM

Originally posted by deadwolfbones

You don't think every company does this for every lens they make?

Sorry I didn't get that, I was just suggesting that photozone should have tested it as same resolution (10MP instead of 16MP) so that comparison with other lenses was easier.

the swede · 04-21-2011, 09:34 AM

Very sad that many people rely and trust so hard on the PZ test when its still possible that the lens Klaus tested was a dud.

I stated somewhere else that Pentax is in fact known for sending back faulty lenses some times. Its called "within factory specs" and i have personaly seen this happen with a DA 40 Ltd and a DA* 50-135.

They do lab tests at given points but if the lens produce faults outside of that..... well there is the "within factory specs" excuse. They still can provide test resuts that prove the lens to be correct, in the area they test the lens.

Still.... i can not prove the PZ wrong, and i cant convince anyone. Just saying what i have experienced myself.

frogfoot · 04-21-2011, 10:23 AM

Originally posted by GeneV

but different people have different definitions of "unusable"

This is what I call unusable. Comparison between 18-135 and 50-200: 100% crop of right lower corner.
BTW at wide to middle range my 18-135 is noticeably sharper and more contrast than 16-45 (I'm talking about center. Corners are still weaker). So I don't know if my lens can be called faulty.

P.S. After more careful examination I can say that 18-135 is not worse than 50-200 in the range of 50-100 mm.

deadwolfbones · 04-21-2011, 10:28 AM

Originally posted by yusuf

Sorry I didn't get that, I was just suggesting that photozone should have tested it as same resolution (10MP instead of 16MP) so that comparison with other lenses was easier.

Ah, sorry. I thought you were talking about a different "they."

Parallax · 04-21-2011, 10:41 AM

frogfoot, the 18-135 shot looks to me like motion blur, not focus or "softness".

frogfoot · 04-21-2011, 10:49 AM

Originally posted by Parallax

frogfoot, the 18-135 shot looks to me like motion blur, not focus or "softness".

It can't be motion blur. The picture was taken at 1/200 s and using a tripod. The center of the image has no such doubled edges.

Parallax · 04-21-2011, 10:50 AM

Was SR off?

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04-21-2011, 05:08 AM	#121
dgaies Veteran Member Join Date: Oct 2009 Location: Maryland / Washington DC Posts: 3,917	Originally posted by Spotmatic Maybe the PZ review will cause the price to drop? It's quite possible I got my 18-135 pretty cheap (around $300 when all was said and done), so as I've said in previous posts, perhaps my expectations are lower as a result.

04-21-2011, 05:32 AM	#122
frogfoot Forum Member Join Date: Apr 2011 Location: Moscow Posts: 70	Originally posted by Rondec Right here: https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/140953-superzo...ml#post1472037. Thanks... Hm.. It looks like his 18-135 is sharper at 135 mm than 18-250... As for me I found my 18-135 quite unusable at 100 mm and above...

04-21-2011, 06:16 AM	#123
audiobomber Veteran Member Join Date: May 2008 Location: Sudbury, Ontario Photos: Albums Posts: 6,806	Originally posted by frogfoot Thanks... Hm.. It looks like his 18-135 is sharper at 135 mm than 18-250... As for me I found my 18-135 quite unusable at 100 mm and above... One has to wonder if this is a Pentax quality control issue.

04-21-2011, 06:57 AM	#124
yusuf Pentaxian Join Date: Nov 2008 Location: Palo Alto, CA Photos: Gallery Posts: 2,497	I was never enthusiast about this lens. They should have tested at same resolution to compare MTF against other lenses.

04-21-2011, 07:13 AM	#125
deadwolfbones Veteran Member Join Date: Sep 2007 Location: La Crescenta, CA Posts: 7,450	Originally posted by yusuf I was never enthusiast about this lens. They should have tested at same resolution to compare MTF against other lenses. You don't think every company does this for every lens they make?

04-21-2011, 07:40 AM	#126
GeneV Veteran Member Join Date: Oct 2008 Location: Albuquerque NM Photos: Albums Posts: 9,830	Originally posted by audiobomber One has to wonder if this is a Pentax quality control issue. QC is quite possibly an issue, but different people have different definitions of "unusable" as well. I've heard people call the kit lens unusable, and I find it quite handy in many situations.

04-21-2011, 08:36 AM	#127
Menno New Member Join Date: Sep 2006 Location: Netherlands Photos: Gallery Posts: 10	Originally posted by audiobomber My 18-135 has better sharpness than my 18-250 in the center and across the frame, at 18mm and 135mm. I only tested wide open because the gap disappears as the apertures close. https://picasaweb.google.com/bonhommed/18135Vs18250# I haven't tried 18mm against a brick wall but in landscape test-shots the borders with my 18-135 at 18mm f3.5 were much softer than I see on your samples. The field curvature thing could explain that it's not to the same degree in every scene. Originally posted by audiobomber I'll believe a 50-200 is sharper when I see it confirmed. Sharpness is not comparable on the PZ tests due to different bodies, and I strongly suspect the lens used was substandard (not Klaus' fault). Above 75mm my DA50-200 performs better in every way than my 18-135 except for autofocus. But it all depends on what copy you get I suppose. I've posted a 100% crop here on the other forum: big 100% crop: Pentax SLR Talk Forum: Digital Photography Review

04-21-2011, 09:14 AM	#128
Eruditass Veteran Member Join Date: Jul 2009 Photos: Gallery Posts: 2,207	Originally posted by audiobomber One has to wonder if this is a Pentax quality control issue. I think with consumer lenses, quality varies pretty widely, often greater than average performance between different lens models, with the minimum bar set rather low. Stellar performers are often not really supposed to be stellar, luck just granted them a good one.

04-21-2011, 09:15 AM	#129
yusuf Pentaxian Join Date: Nov 2008 Location: Palo Alto, CA Photos: Gallery Posts: 2,497	Originally posted by deadwolfbones You don't think every company does this for every lens they make? Sorry I didn't get that, I was just suggesting that photozone should have tested it as same resolution (10MP instead of 16MP) so that comparison with other lenses was easier.

04-21-2011, 09:34 AM	#130
the swede Inactive Account Join Date: Aug 2009 Posts: 2,310	Very sad that many people rely and trust so hard on the PZ test when its still possible that the lens Klaus tested was a dud. I stated somewhere else that Pentax is in fact known for sending back faulty lenses some times. Its called "within factory specs" and i have personaly seen this happen with a DA 40 Ltd and a DA* 50-135. They do lab tests at given points but if the lens produce faults outside of that..... well there is the "within factory specs" excuse. They still can provide test resuts that prove the lens to be correct, in the area they test the lens. Still.... i can not prove the PZ wrong, and i cant convince anyone. Just saying what i have experienced myself.

04-21-2011, 10:28 AM	#132
deadwolfbones Veteran Member Join Date: Sep 2007 Location: La Crescenta, CA Posts: 7,450	Originally posted by yusuf Sorry I didn't get that, I was just suggesting that photozone should have tested it as same resolution (10MP instead of 16MP) so that comparison with other lenses was easier. Ah, sorry. I thought you were talking about a different "they."

04-21-2011, 10:41 AM	#133
Parallax Senior Moderator Loyal Site Supporter Join Date: Apr 2008 Location: South Dakota Photos: Gallery Posts: 19,332	frogfoot, the 18-135 shot looks to me like motion blur, not focus or "softness".

04-21-2011, 10:49 AM	#134
frogfoot Forum Member Join Date: Apr 2011 Location: Moscow Posts: 70	Originally posted by Parallax frogfoot, the 18-135 shot looks to me like motion blur, not focus or "softness". It can't be motion blur. The picture was taken at 1/200 s and using a tripod. The center of the image has no such doubled edges.

04-21-2011, 10:50 AM	#135
Parallax Senior Moderator Loyal Site Supporter Join Date: Apr 2008 Location: South Dakota Photos: Gallery Posts: 19,332	Was SR off?