Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
05-03-2011, 01:57 PM   #1
Site Supporter
Site Supporter
mattt's Avatar

Join Date: Feb 2011
Location: Niagara
Photos: Gallery | Albums
Posts: 2,820
CA and how I can avoid it / correct it

Hi folks,
Still learning lots, trying different things. I was messing around in the garden. Tulips have popped yay!I think I would identify the phenomenon below as chromatic aberation... would that be correct. Is there any thing I can do in set up to eliminate this? I know, focus is not spot on.

Today with K-r + FA 50mm F1.4 equipped with a b+W F-Pro UV filter. Pretty steep crop of 1/200 @ 200 ISO f2.2

Link to original here: http://flic.kr/p/9EnSZf


Last edited by mattt; 11-02-2014 at 07:24 PM.
05-03-2011, 01:58 PM   #2
Administrator
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 43,741
Tips for avoiding ca:
-stop down
-be in focus
-avoid overexposure
-avoid bright edges and direct sunlight
05-03-2011, 02:12 PM   #3
Site Supporter
Site Supporter
mattt's Avatar

Join Date: Feb 2011
Location: Niagara
Photos: Gallery | Albums
Posts: 2,820
Original Poster
Seems pretty straight forward - thanks.
05-03-2011, 02:49 PM   #4
Veteran Member
KxBlaze's Avatar

Join Date: Feb 2010
Location: California
Photos: Gallery
Posts: 1,594
Try shooting at or around F8 is the most common and easy method. The second I think is much harder because you have less control over it and that is to avoid big contrast differences. Shooting birds against a bright blue sky will produce massive amounts of CA but is almost unavoidable if you are trying to photograph birds.

You can also fix it (or at least minimize it) with good software. I use Photoshop and can get rid of a lot of CA.

05-03-2011, 03:53 PM   #5
Pentaxian
kh1234567890's Avatar

Join Date: Sep 2010
Location: Manchester, UK
Photos: Gallery
Posts: 2,416
That's not CA but probably blooming or 'softness' of the lens. CA would be distinct red/blue or yellow/magenta colour bands at non radial edges in the image. Also CA would not appear in the centre of the frame. Stop down more and get rid of that filter. Or use a better lens
05-03-2011, 04:09 PM   #6
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,401
QuoteOriginally posted by kh1234567890 Quote
That's not CA but probably blooming or 'softness' of the lens. CA would be distinct red/blue or yellow/magenta colour bands at non radial edges in the image. Also CA would not appear in the centre of the frame. Stop down more and get rid of that filter. Or use a better lens
Normally, lateral CA is purple or magenta one side of th eOut of focus image and green on the other, longitudinal is usually purple on both sides of OOF images in front of the plane of focus and green on both sides behind the plane of focus.

I would agree here, it may be more spherical aberations, caused by a fast lens that does not focus all parts of the image at the same place, due to the ourer parts of the lens having a different focus point than the central parts of the lens.

Regardless both go away to some extent as you stop down.
05-03-2011, 08:25 PM   #7
Site Supporter
Site Supporter
mattt's Avatar

Join Date: Feb 2011
Location: Niagara
Photos: Gallery | Albums
Posts: 2,820
Original Poster
Great feedback, thanks guys. Working with the large apertures is a bit of a trick... truth be told if I wasnt pixel peeping I wouldn't have noticed. Dont even recall why I was looking so close.
05-03-2011, 10:50 PM   #8
Senior Member




Join Date: Oct 2010
Location: South Yorkshire
Photos: Gallery
Posts: 147
Definitely not CA, as has been stated; in the tulip shot it's either camera shake or subject movement. And yes, pixel peeping causes a lot of heartache - does it to me all the time!

05-03-2011, 11:04 PM   #9
Pentaxian
JohnBee's Avatar

Join Date: Sep 2008
Location: front of computer
Posts: 4,630
QuoteOriginally posted by The Jannie Quote
Definitely not CA, as has been stated; in the tulip shot it's either camera shake or subject movement. And yes, pixel peeping causes a lot of heartache - does it to me all the time!
Could be blooming due to aperture too.
Also, it almost looks as though its being emphasized in PP as well.
05-04-2011, 02:29 AM   #10
Veteran Member
sany's Avatar

Join Date: Mar 2011
Location: Dubai, UAE
Photos: Gallery | Albums
Posts: 428
QuoteOriginally posted by Adam Quote
Tips for avoiding ca:
-stop down
-be in focus
-avoid overexposure
-avoid bright edges and direct sunlight
By the term 'stop down' is that saying reduce the aperture size!?
05-04-2011, 03:56 AM   #11
Site Supporter
Site Supporter
mattt's Avatar

Join Date: Feb 2011
Location: Niagara
Photos: Gallery | Albums
Posts: 2,820
Original Poster
QuoteOriginally posted by sany Quote
By the term 'stop down' is that saying reduce the aperture size!?
Yes.

QuoteOriginally posted by JohnBee Quote
looks as though its being emphasized in PP as well
Aside from crop, there was none.
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!
camera, pentax help, photography
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
New ACR Lens Correct vs K-5 in Camera Correct emblemex Pentax K-5 12 12-08-2010 12:20 PM
best ways to avoid theft when abroad ? beer_nuts Photographic Technique 25 08-30-2010 10:40 PM
Buying Used Equipments - How to Avoid Duty/Tax Charges Doanh General Talk 17 02-19-2010 10:02 PM
how to avoid too bright pictures rustynail925 Photographic Technique 16 09-30-2009 07:22 PM
How to avoid Jpeg artifacting? MoparFreak69 Digital Processing, Software, and Printing 12 09-25-2009 08:43 AM



All times are GMT -7. The time now is 10:58 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