Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
12-16-2013, 11:38 AM   #16
Forum Member




Join Date: Jan 2012
Posts: 87
Sandy, I have been testing my 20-40 against a lot of my good lenses. Mine may be a bit decentered wide open, favoring the left side. But I noticed it's not that great at 20/2.8. Mine is basically an f4 lens, like my FA 20-35 for example. It outperformed my FA 20-35 at the edges in general. But in the center, my Pentax 16-50, 17-70, and Sigma 18-250 macro (a $400 super zoom) were just as good. And it's larger than I thought. So it's has a very limited range, not wide enough (should have started at 16 or 18), not that small (similar to Sigma 18-250 w/o hood), and of course very expensive. Focusing is OK, not that fast. It's great in the 30-40mm range for sure.

I'm not sure if I will keep the lens. Clearly the much heavier, larger Sigma 18-35 is the better lens optically.

12-16-2013, 12:21 PM   #17
Loyal Site Supporter
TedH42's Avatar

Join Date: Dec 2011
Location: Colorado
Photos: Gallery
Posts: 475
QuoteOriginally posted by rdj92807 Quote
Sandy, I have been testing my 20-40 against a lot of my good lenses. Mine may be a bit decentered wide open, favoring the left side. But I noticed it's not that great at 20/2.8. Mine is basically an f4 lens, like my FA 20-35 for example. It outperformed my FA 20-35 at the edges in general. But in the center, my Pentax 16-50, 17-70, and Sigma 18-250 macro (a $400 super zoom) were just as good.
How does it compare to the FA 20-35 in the center? For me personally, that's its competition. From what I am reading and seeing, it seems to have a more uniform-across-the-field IQ, with IQ in the center apparently traded off for better IQ in the edges.
12-16-2013, 12:45 PM   #18
Pentaxian




Join Date: Nov 2011
Photos: Gallery | Albums
Posts: 3,688
QuoteOriginally posted by TedH42 Quote
From what I am reading and seeing, it seems to have a more uniform-across-the-field IQ, with IQ in the center apparently traded off for better IQ in the edges.
That seems consistent with the general DA Limited philosophy,
seen particularly in the pancakes (but not so much in the DA 15).
12-16-2013, 12:52 PM   #19
Pentaxian




Join Date: Nov 2011
Photos: Gallery | Albums
Posts: 3,688
QuoteOriginally posted by rdj92807 Quote
And it's larger than I thought.
It was always expected to be about the same size as the FA 20-35.
DA zooms don't come much smaller.

QuoteOriginally posted by rdj92807 Quote
not wide enough (should have started at 16 or 18), not that small
Wider would have meant larger.

QuoteOriginally posted by rdj92807 Quote
Clearly the much heavier, larger Sigma 18-35 is the better lens optically.
If you're against the light, that may not be as clear.

12-16-2013, 12:58 PM   #20
Senior Member




Join Date: Feb 2011
Location: St.-Petersburg
Photos: Albums
Posts: 145
QuoteOriginally posted by rdj92807 Quote
Clearly the much heavier, larger Sigma 18-35 is the better lens optically.
The typical Sigma's color rendition and saturation are unfortunately far away from the Pentax DA* and Lim. You can look on the next thread "20-40 for testing, I have post three pictures from the similar point of view: Sigma 10-20, DA* 16-50 and Lim 20-40. The difference is great, IMHO.
But, of course, some people may prefer sharpness against bokeh or color. I am also like the very sharp lenses but I am use Sigma only because Pentax does not have the lenses with "my" focal ranges.
(This is not for the starting the holy war Pentax against Sigma or sharpness against color and bokeh.)
12-16-2013, 01:52 PM - 1 Like   #21
Forum Member




Join Date: Jan 2012
Posts: 87
Grokh, your comments about Sigma color are no longer true, with their new lenses. They have really improved their coatings.
Testing my Sig 18-250 at 20mm and 40mm, you can really not see any major color difference between it and the 20-40 ltd.
Older Sigma lenses had a yellow cast and lesser color vs Pentax, for sure. I bet the Sigma 18=35 colors will be just as good as Pentax at this point.

Ted, re the FA 20-35, here are my test results:

Overall, somewhat better contrast than FA 20-35

At 20mm 4.0 the 20-40 sharpness center/corner was close but FA 20-35 was better; my 20-40 copy is decentered and weak on the right. Same at 5.6. At 8.0, 20-40 finally slightly better at edges.

At 24mm, 20-40 beats my FA 20-35 at edges at 4.0 and 5.6; are equal at 8.0

At 35mm, 20-40 beats my FA 20-35 with much better edges at 4.0, slightly better at 5.6 and 8.0

Again, no question this lens can perform very well 24 to 40. My issue is at 20mm, which given that is 30mm in 35mm format and not that wide, will be used extensively by most people. I would prefer strength at 20, and less at 40 if a compromise was needed. My FA 20/2.8 was WAY better than the 20-40 at 2.8 and 4.0, for example. In fairness, the 20-40 is way better than my Pentax 16-50 at 20 and 2.8 at the far edges (not center), so every lens has it's issues. The Pentax 16-50, for edges, is just not great at 2.8 but really improves by 4.0.

So I'm really struggling with my feelings on the 20-40. I am leaning toward the Sigma 18-35 when it comes out. Yes, it's bigger and heavier but SO much sharper and faster, by all reports. Many lenses can match the 20-40 at 20, and it's range is just so limited for the slower speed.

Last edited by rdj92807; 12-16-2013 at 02:00 PM.
12-16-2013, 02:02 PM   #22
Senior Member




Join Date: Feb 2011
Location: St.-Petersburg
Photos: Albums
Posts: 145
QuoteOriginally posted by rdj92807 Quote
Grokh, your comments about Sigma color are no longer true, with their new lenses. They have really improved their coatings
My Sigma 10-20 is two years old, the color difference is too big. My new Sigma 50-500 has been bought this year, it is much better than my previous Bigma, but the color rendition still not the same as by DA* 60-250. But of course, current Sigma is not the same as three-four years ago.
12-16-2013, 04:26 PM   #23
Loyal Site Supporter
TedH42's Avatar

Join Date: Dec 2011
Location: Colorado
Photos: Gallery
Posts: 475
QuoteOriginally posted by rdj92807 Quote
Ted, re the FA 20-35, here are my test results:

Overall, somewhat better contrast than FA 20-35

At 20mm 4.0 the 20-40 sharpness center/corner was close but FA 20-35 was better; my 20-40 copy is decentered and weak on the right. Same at 5.6. At 8.0, 20-40 finally slightly better at edges.

At 24mm, 20-40 beats my FA 20-35 at edges at 4.0 and 5.6; are equal at 8.0

At 35mm, 20-40 beats my FA 20-35 with much better edges at 4.0, slightly better at 5.6 and 8.0
Thanks for your comparison of your FA 20-35 and DA 20-40. For me, the jury is still out. I really like my FA 20-35, and the DA 20-40 has to step up to knock it out. Not yet sure if it does for me. Still looking at the evidence.

12-16-2013, 04:28 PM   #24
Pentaxian




Join Date: Mar 2010
Location: SW Washington
Posts: 814
QuoteOriginally posted by Adam Quote
And twice the size of any limited prime
If it were twice the size of the FA 31 LImited, it would be quite the monstrosity.
12-16-2013, 07:54 PM   #25
Veteran Member
krebsy75's Avatar

Join Date: Jun 2010
Location: Chester County, Pa.
Posts: 804
This glass gets points for WR and classic industrial design. Not sure how points equates to dollars. That's up to you.
12-16-2013, 08:44 PM   #26
Site Supporter




Join Date: Aug 2009
Location: Asheville
Posts: 32
QuoteOriginally posted by Adam Quote
And twice the size of any limited prime I myself expected it to be a lot smaller, I suppose the weather sealing might add to its size. It's not bad at all but IMO, it feels a bit like an oddball compared to the other Limiteds. Makes a great close-up lens, though!



This time we're probably just going to jump right in to the in-depth review. It'll definitely be posted before the end of the year
Can't wait. PF may be the first out with an in-depth review.
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!
20-40mm, 20-40mm af test, af, k-mount, pentax lens, slr lens, test, video
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Voigtlander Ultron 40mm f/2 vs. Pentax 40mm Ltd (warning: amateur test) dasuhu Pentax SLR Lens Discussion 48 12-05-2013 08:34 AM
20-40mm Limited reviewed David&karen Pentax SLR Lens Discussion 52 11-29-2013 12:30 AM
K-5 IIs Low-Light AF test video Adam Pentax K-5 61 07-26-2013 02:14 AM
Quick and dirty test SMC-M 40mm vs XS 40mm - judge for yourself manntax Pentax SLR Lens Discussion 3 06-27-2013 10:09 AM
First PENTAX K-5 II Test Video (AF Speed)!!! ogunturkay Pentax K-5 12 09-18-2012 03:40 PM



All times are GMT -7. The time now is 03:49 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