Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
05-07-2012, 07:30 PM   #1
Veteran Member




Join Date: Mar 2012
Photos: Gallery
Posts: 307
18-135mm is objectively a bad lens

Not sure how people can consciously recommend 18-135mm when it has such a poor performance. It is very sharp in the center but extremely soft in the corners at wide open. From 50mm onward, no matter how much stopped down, the corners are not sharp. I am not even sure my copy is bad as my experience and tests seem to confirm the results published in the several reviews (the ones with MTF charts). I would say the lens is probaby useable between 24-50. Thoughts welcome.

So, should I get another copy and play the chance game for an "exceptionally good" copy or just return and think over my rainy-day option?

Potential options:

DFA 100 WR - too long for most of my needs

DA* 16-50 - too expensive for the quality and SDM

DA* 50-135 - too expensive and SDM

DA 18-55 WR - not long enough and too low in contrast and not that sharp anywhere

DA* 50-250 - too expensive, too long and too heavy


Last edited by chesebert; 05-07-2012 at 07:47 PM.
05-07-2012, 07:39 PM   #2
Emperor and Senpai
Loyal Site Supporter
VoiceOfReason's Avatar

Join Date: Jun 2010
Location: Nashville, IN
Posts: 5,427
If you're wanting to get rid of one....
05-07-2012, 07:52 PM   #3
Administrator
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 43,668
I personally like the lens, as delivers a handy zoom range, is compact, is weather sealed, and focuses quickly. You can't get everything, though, and in this case, the IQ suffers a bit. It's more than adequate for my purposes, which include shooting events and parties. Whenever I need real IQ, I switch to primes.

Adam
PentaxForums.com Webmaster (Site Usage Guide | Site Help | My Photography)



PentaxForums.com's high server and development costs are user-supported. You can help cover those costs by donating. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

05-07-2012, 07:58 PM   #4
Veteran Member




Join Date: Feb 2012
Location: Fredericton, New Brunswick
Photos: Gallery
Posts: 631
As Adam said, if IQ is an issue, switch to some primes - Personally, I'm growing to dislike my 18-135, but I still like it in the sense that I can throw a single lens on and be fine for 97% of situations. In regards to sharpness wide open, you must realize, this is a "Enthusiast" quality(and price) lens, typically that means wide open, you're going to get sub-par results. My advice is invest in a good flash and shoot at f8 whenever possible. Seems to get quite sharp around there.(Just don't go past 8, or you'll get the dreaded vignetting)

Though I can see where you're coming from - Actually considered selling mine to use the cash to pick up some more primes, or maybe partially fund a DA* purchase..

Edit: Also, don't shoot at extremes on a super-zoom and expect A+ quality, when there's that many shifted elements, stuff is bound to go awry.

05-07-2012, 08:14 PM   #5
Pentaxian




Join Date: Jun 2011
Location: NJ
Photos: Gallery
Posts: 4,899
Actually, it's your opinion that the 18-135 is a bad lens. Your criteria may not match others who more value:

- small size
- quick, quiet AF
- WR
- color & contrast
- center sharpness

Some people don't require sharp edges for their photographic needs. If you strongly dislike this flaw in the lens, then you shouldn't even bother hoping for a "good" copy, as soft edges are a result of field curvature, and thus inherit in the design of the lens.
05-07-2012, 08:15 PM   #6
Emperor and Senpai
Loyal Site Supporter
VoiceOfReason's Avatar

Join Date: Jun 2010
Location: Nashville, IN
Posts: 5,427
I am definitely going to pick one up for my hiking. I'll save my non-weather sealed stuff for other times. Now if only I can find one of these on the used market for 300 dollars. I guess patience is the word of the day!
05-07-2012, 08:16 PM   #7
Veteran Member




Join Date: Mar 2012
Photos: Gallery
Posts: 307
Original Poster
QuoteOriginally posted by Eulogy Quote
As Adam said, if IQ is an issue, switch to some primes - Personally, I'm growing to dislike my 18-135, but I still like it in the sense that I can throw a single lens on and be fine for 97% of situations. In regards to sharpness wide open, you must realize, this is a "Enthusiast" quality(and price) lens, typically that means wide open, you're going to get sub-par results. My advice is invest in a good flash and shoot at f8 whenever possible. Seems to get quite sharp around there.(Just don't go past 8, or you'll get the dreaded vignetting)

Though I can see where you're coming from - Actually considered selling mine to use the cash to pick up some more primes, or maybe partially fund a DA* purchase..

Edit: Also, don't shoot at extremes on a super-zoom and expect A+ quality, when there's that many shifted elements, stuff is bound to go awry.
That's all good, except even at f8, corner/edge performance at >50mm is just dreadful.

QuoteOriginally posted by luftfluss Quote
Actually, it's your opinion that the 18-135 is a bad lens. Your criteria may not match others who more value:

- small size
- quick, quiet AF
- WR
- color & contrast
- center sharpness

Some people don't require sharp edges for their photographic needs. If you strongly dislike this flaw in the lens, then you shouldn't even bother hoping for a "good" copy, as soft edges are a result of field curvature, and thus inherit in the design of the lens.
I can confirm all those positive attributes. But nevertheless, this lens fails on basic optical parameter.
05-07-2012, 08:24 PM   #8
Pentaxian




Join Date: Jun 2011
Location: NJ
Photos: Gallery
Posts: 4,899
QuoteOriginally posted by chesebert Quote
I can confirm all those positive attributes. But nevertheless, this lens fails on basic optical parameter.
Given the high regard many users have for the lens,what you opine is a "fail" just doesn't bug that many people. It would bother me, so I never seriously considered buying it.

05-07-2012, 08:28 PM   #9
Veteran Member




Join Date: Mar 2012
Photos: Gallery
Posts: 307
Original Poster
QuoteOriginally posted by Adam Quote
I personally like the lens, as delivers a handy zoom range, is compact, is weather sealed, and focuses quickly. You can't get everything, though, and in this case, the IQ suffers a bit. It's more than adequate for my purposes, which include shooting events and parties. Whenever I need real IQ, I switch to primes.
Is your copy sharp in the center from 50-135mm? Mine is not sharp in that range (not as sharp as center from 24-45).

At 135mm, the whole image is just one mushy mess, compared to 24-45, IMO.
05-07-2012, 08:30 PM   #10
Administrator
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 43,668
QuoteOriginally posted by chesebert Quote
Is your copy sharp in the center from 50-135mm? Mine is not sharp in that range (not as sharp as center from 24-45).
Yup, it is. I've only noted issues in the corners.

Adam
PentaxForums.com Webmaster (Site Usage Guide | Site Help | My Photography)



PentaxForums.com's high server and development costs are user-supported. You can help cover those costs by donating. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

05-07-2012, 08:33 PM   #11
Veteran Member
Jodokast96's Avatar

Join Date: Oct 2007
Location: Erial, NJ USA
Photos: Gallery | Albums
Posts: 2,132
You could always look for a 17-70.
05-07-2012, 08:34 PM   #12
Forum Member




Join Date: Feb 2012
Location: Philadelphia
Posts: 88
I do like my 17-70mm fwiw. And if you're shooting a k-5 you can get away w/ a slight crop to "extend" the focal length range. I have no experience w/ the lens in question though, sorry. If you know what subjects and circumstances you'll be shooting then yes you can work around known limitations, so the lens' shortcomings might not matter. I think the 18-135mm would bum me out, if judged by what I read, as applied to what I often shoot.
05-07-2012, 08:37 PM   #13
Veteran Member
liukaitc's Avatar

Join Date: Jul 2010
Location: New York
Photos: Albums
Posts: 1,008
The resolution chart on photozone is absolutely terrible, but the sample photo they provided looks fine...

Last edited by liukaitc; 05-07-2012 at 08:42 PM.
05-07-2012, 08:43 PM   #14
Veteran Member




Join Date: Mar 2012
Photos: Gallery
Posts: 307
Original Poster
QuoteOriginally posted by Jodokast96 Quote
You could always look for a 17-70.
I am looking for a rainy day lens, and 17-70 is non WR IIRC.
05-07-2012, 08:44 PM   #15
Veteran Member




Join Date: Mar 2012
Photos: Gallery
Posts: 307
Original Poster
QuoteOriginally posted by Adam Quote
Yup, it is. I've only noted issues in the corners.
Ok. Perhaps I don't have a good copy. Now, when you say sharp did you do a manual focus test or are you just basing on actual photos?
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
18-135mm, copy, corners, da*, k-mount, lens, pentax lens, sdm, slr lens, wr
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Bad lens or bad polerizer TRAINUT Pentax Camera and Field Accessories 3 04-30-2012 12:43 PM
Help, new lens is bad? Kitty Troubleshooting and Beginner Help 8 01-10-2012 06:26 PM
Tips on how to objectively rate photos Zafar Iqbal Digital Processing, Software, and Printing 37 01-02-2012 07:44 AM
135mm Takumar Bayonet Ain't So Bad warpedwoof Pentax SLR Lens Discussion 17 04-25-2009 01:18 AM
Tamron Adaptall... Bad lens or bad adapter Okami Pentax SLR Lens Discussion 6 05-01-2008 06:52 PM



All times are GMT -7. The time now is 05:40 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top