Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
04-29-2010, 09:43 PM   #1
Inactive Account




Join Date: Jan 2010
Posts: 11
Pentax DA 12-24mm purple fringing monster? correctable?

there is some talk going on about the Pentax 12-24mm and i although thought about buying this lens. i read all the reviews and i know it's weakness is purple fringing.

in these reviews they always point out that it's easily correctable in post processing. so i looked at many pictures taken with this lens and almost every picture with some harsh contrast shows massive blue, green and blue fringing.

i attached some findings.

i tried to correct them in Lightroom3 beta but failed to completely remove them or keep the quality good enough. anybody can tell me if it's possible and if yes how?

Attached Images
View Picture EXIF
PENTAX K20D  Photo 
View Picture EXIF
PENTAX K20D  Photo 
View Picture EXIF
PENTAX K20D  Photo 
View Picture EXIF
PENTAX K20D  Photo 
View Picture EXIF
PENTAX K20D  Photo 
04-29-2010, 09:45 PM   #2
Inactive Account




Join Date: Jan 2010
Posts: 11
Original Poster
another bunch if samples
Attached Images
View Picture EXIF
PENTAX K20D  Photo 
View Picture EXIF
PENTAX K20D  Photo 
View Picture EXIF
PENTAX K20D  Photo 
View Picture EXIF
PENTAX K20D  Photo 
View Picture EXIF
 Photo 
04-29-2010, 10:19 PM - 1 Like   #3
Inactive Account




Join Date: Aug 2008
Location: Michigan, USA
Photos: Gallery | Albums
Posts: 7,484
Quality is going to be subjective for this but here's one way I go about it. I've found, and this is true with All of my lenses, it's a matter of not over exposing the shot and getting the WB looking right. You can see in the window, how this shot started out (the picture is of the dog at the back fence). These are screen shots from ACR. These steps can also be taken in Lightroom.



The First thing I do is adjust the White balance to kill most of the fringing.. So we go from this..



To This.



After that I go up close and personal to adjust the CA sliders and kill or balance out as much of the remaining stuff as possible.



I do my sharpening, contrast adjustments, etc then open the image for the final JPG edit. In this case, it's bringing down the exposure of the sky to give it some detail. Then applying masks where I do (or don't) want the effect to happen.



Remember, I said the picture is of the dog.



This doesn't work with everything but it worked great here. I've said it before, I'll say it again, and again. I can make ANY lens Fringe. It helps though to get it right the first time.

This Is a crop but there was no CA/PF correction done.



04-29-2010, 11:01 PM   #4
Veteran Member
Pentaxor's Avatar

Join Date: May 2009
Location: Vancouver, B.C.
Photos: Gallery
Posts: 6,513
very helpful tutorial Jeff.

since you already mentioned some PP work, I would like to point out some basics or things that would make PP less work.

here is what I do first. I decrease the contrast depending on the light intensity of the shot. try to shoot at around 14mm or more whenever possible. CA/PF is very strong at 12mm. avoid shooting at f4 if light intensity is strong. I would recommend f8 or over. if you have done these steps, post-processing later on would be much easier.

oh and there is the simplest and easiest solution of avoiding and eliminating PF/CA completely. shoot B&W.

04-30-2010, 03:57 AM   #5
JHD
Veteran Member




Join Date: Jan 2010
Photos: Albums
Posts: 1,407
QuoteOriginally posted by Pentaxor Quote
oh and there is the simplest and easiest solution of avoiding and eliminating PF/CA completely. shoot B&W.

or just get a Sigma 10-20
04-30-2010, 06:22 AM   #6
Pentaxian
Wheatfield's Avatar

Join Date: Apr 2008
Location: The wheatfields of Canada
Posts: 10,154
QuoteOriginally posted by JHD Quote
or just get a Sigma 10-20
I expect it can be made to PF if someone tries hard enough.
04-30-2010, 09:09 AM   #7
Inactive Account




Join Date: Jan 2010
Posts: 11
Original Poster
i've checked the exif data of this samples and it's true most of them where shot below f8 (but most of them one stop below) and between 12-16mm. in terms of usability this means i should avoid using it's wider end on bright days or stopping it down if possible.

thanks jeff for the tut how you manage the CA with this lens. what about the lens profiles in adobe's new camera raw?
i saw i short movie how these lens profiles could correct most of the lens CA and distortion. i wonder how this works out for this lens because this would be a one click action.

this is the only area where the sigma beats the pentax and i still prefer the pentax because of it's longer end.
04-30-2010, 10:20 AM   #8
Veteran Member
Pentaxor's Avatar

Join Date: May 2009
Location: Vancouver, B.C.
Photos: Gallery
Posts: 6,513
QuoteOriginally posted by testlord Quote
i've checked the exif data of this samples and it's true most of them where shot below f8 (but most of them one stop below) and between 12-16mm. in terms of usability this means i should avoid using it's wider end on bright days or stopping it down if possible.

thanks jeff for the tut how you manage the CA with this lens. what about the lens profiles in adobe's new camera raw?
i saw i short movie how these lens profiles could correct most of the lens CA and distortion. i wonder how this works out for this lens because this would be a one click action.

this is the only area where the sigma beats the pentax and i still prefer the pentax because of it's longer end.
just be aware that it doesn't eliminate CA completely but minimize the intensity of CA to a low level.

also mind you that any lens will display a certain level of CA under extreme conditions.

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!
12-24mm, k-mount, lens, pentax, pentax da 12-24mm, pentax lens, reviews, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
DA 10-17 purple fringing rpriedhorsky Pentax SLR Lens Discussion 13 02-07-2009 04:46 AM
Purple fringing on DA* 16-50 spinmar Pentax SLR Lens Discussion 14 02-03-2009 07:03 AM
Purple Fringing paolojackson Digital Processing, Software, and Printing 2 10-06-2008 05:25 PM
Oh no! Purple fringing! NaClH2O Post Your Photos! 6 03-27-2008 05:28 AM
Purple Fringing Stratman Pentax SLR Lens Discussion 7 04-29-2007 01:07 PM



All times are GMT -7. The time now is 07:11 PM. | 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