Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
04-05-2010, 07:28 AM   #1
Veteran Member
TKH's Avatar

Join Date: Aug 2007
Location: Germany
Posts: 371
What do you think about this copy of the DA15mm?

I bought this DA15 a year ago via eBay from SRS Microsystems in the UK.
I posted a few nice pics here and was happy. But now I am a little afraid of the results I see sometimes from the lens. I sent the lens two times to Pentax Germany and they quoted me both times "Lens adjusted".

Lets see:

f8; 1/1000


crop


f6.7; 1/350


Crop




I think the foreground is nearly perfect, but the out of focus areas in the corner are sometimes very blurry. For example crop 1. The ships in the middle who are mutch wider away are clear, the nearer ships in the corner are ..... .

Am I to critical in the view of the lens?

Please tell me your view.

Best,
Rainer

04-05-2010, 07:42 AM   #2
Senior Member




Join Date: Jan 2010
Location: Pemberton BC
Posts: 238
The corner blur is very similar to my copy of the DA15 - I expect the centre to be sharpest, but I too am curious if this is considered excessive.
04-05-2010, 08:04 AM   #3
Veteran Member




Join Date: Apr 2009
Location: Singapore
Posts: 384
Allow me to share my opinion

I read DP Review's report and remembered it emphasised that the 15mm is soft when wide open and certainly not as sharp as we want it to be

From your pictures, I believe you already have a very good copy

By the way, most wide angle lens suffer from curvature of field and this makes them appear less sharp

Central sharpness of your copy is certainly good
04-05-2010, 08:16 AM   #4
Loyal Site Supporter
Loyal Site Supporter
blackcloudbrew's Avatar

Join Date: Mar 2009
Location: Cotati, California USA
Photos: Gallery | Albums
Posts: 3,816
Thanks for posting this thread. I think I just learned something from the OP and responses that I may have read before but it never sunk in. This shows this effect very well. Thanks.

04-05-2010, 10:02 AM   #5
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
QuoteOriginally posted by TKH Quote
I think the foreground is nearly perfect, but the out of focus areas in the corner are sometimes very blurry.
Well, doesn't out of focus generally mean blurry? I'd agree the DA15 has a kind of unique look to the out of focus areas that isn't always the nicest. I'd also observe that that shooting at relatively large apertures as you are, it is hard to get corners in focus with a wide angle lens (DOF is *not* infinite), plus the DA15 is indeed not overly sharp in the corners at wide apertures. But out of focus areas are going to be blurry no matter what. You'd have to stop down much further to get those background in focus. Also experiment with placing focus *behind* your foreground, so the DOF that extends in front of and behind the point of focus encompass both foreground and background.
04-05-2010, 10:30 AM   #6
emr
Guest




QuoteOriginally posted by Just12hvFun Quote
I read DP Review's report and remembered it emphasised that the 15mm is soft when wide open and certainly not as sharp as we want it to be...
But those photos are nowhere near wide open, but f/8.0 and f/6.7. I haven't still tested mine properly, but based on the reviews I was expecting a bit better border resolution at f/8.0.

EDIT: Photozone

04-05-2010, 10:39 AM   #7
TKH
Veteran Member
TKH's Avatar

Join Date: Aug 2007
Location: Germany
Posts: 371
Original Poster
I will have a shootout with the DA15 from user tzcobretti next saturday at the zoo in Münster. We will do that with tripod and so. If his copy is mutch better, I try to ask Pentax for giving my a annother copy of the DA15.

I will report.

Rainer
04-05-2010, 11:16 AM   #8
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
QuoteOriginally posted by emr Quote
But those photos are nowhere near wide open, but f/8.0 and f/6.7.
f/6.7 is as close to wide open as it is to f/11.

QuoteQuote:
I haven't still tested mine properly, but based on the reviews I was expecting a bit better border resolution at f/8.0.
Well, like I said, it's not that easy to create a scene in which the borders are actually in focus, even at f/8, but when I've done it, the corners are as impressive as the numbers suggest. But there remains a particular "look" to the slightly OOF areas that is the least pleasing aspect of this lens, I'd say.

04-05-2010, 02:12 PM   #9
Veteran Member




Join Date: Sep 2007
Location: La Crescenta, CA
Posts: 7,452
Looks a-ok to me.
04-05-2010, 02:32 PM   #10
Veteran Member
henryjing's Avatar

Join Date: Mar 2010
Location: United States
Posts: 467
My lens performs the same too. If you only post the pic on the internet, it doesn't matter.
04-05-2010, 04:16 PM   #11
Veteran Member
kristoffon's Avatar

Join Date: Aug 2008
Location: Brazil
Posts: 532
QuoteOriginally posted by TKH Quote
I think the foreground is nearly perfect, but the out of focus areas in the corner are sometimes very blurry.
LOL, so how do you expect an out of focus area NOT to be blurry?

Try again focusing on the background and see how the foreground looks.

According to the dof calculator the hyperfocal distance for 15mm at f/8 is 1.5m / 4.6ft. This does not mean that everything will be pin sharp though! Specially in corners where the light isn't going through the aperture and lenses head on.

In fact your images look like my images shot wth the DA15 in similar situations.
04-05-2010, 05:16 PM   #12
Pentaxian
twitch's Avatar

Join Date: Nov 2009
Posts: 4,571
I'm no expert, but those shots (assuming they are not cropped) look like they were taken with a seriously decentered lens. The right edges are sharp, whilst the left are very blurry. If that isn't a decentered lens then I don't know what is. I wouldn't hesitate to return that lens and get another DA15.
04-05-2010, 07:40 PM   #13
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
I don't see that at all. The crops are only from the left side, so how can you tell anything about the right side? Are you perhaps misinterpreting the crops as being entire pictures? I did that at first and thought the same as you for a momeny, until I realize I was looking at a crop fot he left side only.
04-06-2010, 11:14 PM   #14
Veteran Member
tokyoso's Avatar

Join Date: Jan 2010
Location: Tokyo
Photos: Albums
Posts: 723
how about a crop from the boats on the right side from the second pic?
04-06-2010, 11:26 PM   #15
Veteran Member
wlachan's Avatar

Join Date: Sep 2006
Location: Canada
Photos: Albums
Posts: 2,626
I have observed that OOF and blurry due to misalignment looked a little different which I cannot quite explain in words. What you are showing give me the impression of misalignment, but that is unable to determine w/o some careful tests. The best way to test is to photography some large object like building filling the frame from a distance on tripod w/o SR at every f-stop. Compare the sharpness of all 4 corners and see if they match each other. Though many might disagree, but most Pentax lenses just aren't that great on edge/corner sharpness, and I would be very surprised if the tiny DA15 would be the exception. BTW, optical misalignment cannot be "adjusted" on most Pentax lenses due to the way they have been designed.

Last edited by wlachan; 04-06-2010 at 11:31 PM.
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!
corner, crop, k-mount, lens, pentax lens, ships, slr lens, times, view
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Killer athletic portraits with the DA15mm? Yeyeah! soccerjoe5 Pentax SLR Lens Discussion 30 07-01-2010 09:42 AM
Landscape Rottnest Island w/ DA15mm goddo31 Post Your Photos! 17 02-17-2010 08:14 AM
Wanted - Acquired: Da15mm joeyc Sold Items 0 10-12-2009 01:13 PM
Ultra Wide Angle Primes, DA15mm best choice? David Pentax SLR Lens Discussion 16 06-17-2009 06:06 AM



All times are GMT -7. The time now is 08:13 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