I know that there are plenty of software solutions that offer CA elimination, and with very good results. But why?
What makes CA so easy to correct in digital post processing?
Tanchistu Member 41 posts Joined Jul 2009 More info | Jan 12, 2012 09:55 | #1 I know that there are plenty of software solutions that offer CA elimination, and with very good results. But why?
LOG IN TO REPLY |
Dustman Senior Member  878 posts Likes: 22 Joined Mar 2010 Location: New Jersey More info | Jan 12, 2012 11:16 | #2 I've always had the question on my mind, but never thought to ask here for an awsner, so I'm subsrcibing...............I always was curious why you move a slider and the CA disappears, but all the other colors & tones in the images stay the same, why it doesn't effect anything else??
LOG IN TO REPLY |
tzalman Fatal attraction.  13,497 posts Likes: 213 Joined Apr 2005 Location: Gesher Haziv, Israel More info | Jan 12, 2012 11:40 | #3 CA is caused by the fact that light of different wavelengths (colors) bends by differing amounts when going through the lens and therefore focuses at slightly different spots. An RGB image is usually thought of as having three color values for each pixel, but it can also be conceived of as having three independent color channels or as three images virtually layered one on another. Thus one or two of the layers can be virtually moved laterally to bring them into registration and correct the CA. Elie / אלי
LOG IN TO REPLY |
ratempa Senior Member  438 posts Likes: 37 Joined Jun 2008 Location: San Diego, CA More info | Jan 12, 2012 12:20 | #4 |
1Tanker Goldmember  4,470 posts Likes: 8 Joined Jan 2011 Location: Swaying to the Symphony of Destruction More info | Jan 12, 2012 13:35 | #5 ratempa wrote in post #13692441  It might be just me, but I have yet to see it eliminated. Maybe because i'm a pixel peeper, but it's never perfect. Then again I've only used lightroom ACR and aperture. Maybe you've got some better software. Same here. Using DPP.. i can dumb it down mostly, but there's usually some remnants(especially if pixel-peeped). Some is so bad, that i can't get rid of it all, and that's one of the things that scares me about my great desire for the EF 85 f/1.8..and also steered my thoughts from the Tokina 11-16, to the EF-S 10-22. Kel
LOG IN TO REPLY |
gjl711 "spouting off stupid things"  57,310 posts Likes: 3751 Joined Aug 2006 Location: Deep in the heart of Texas More info | Jan 12, 2012 13:40 | #6 It's easy because it's well understood and very predictable. No software will get rid of every pixel, but DPP, arc, photoshop and others can do a really decent job getting rid of most of it. Not sure why, but call me JJ.
LOG IN TO REPLY |
cdifoto Don't get pissy with me  34,090 posts Likes: 44 Joined Dec 2005 More info | Jan 12, 2012 13:41 | #7 I don't even mess with it. If it's subtle enough to be eliminated, it's subtle enough to be ignored. If it's bad enough to be neither eliminated nor ignored, it's bad enough to sell the lens. Did you lose Digital Photo Professional (DPP)? Get it here
LOG IN TO REPLY |
Jan 12, 2012 14:39 | #8 Because when you look at the digital data it is easy to find with numerical analysis, located along a high contrast edges with predictable hues. Gear List
LOG IN TO REPLY |
RenéDamkot Cream of the Crop  39,856 posts Likes: 8 Joined Feb 2005 Location: enschede, netherlands More info | Jan 14, 2012 11:33 | #9 1Tanker wrote in post #13692852 Same here. Using DPP.. i can dumb it down mostly, but there's usually some remnants(especially if pixel-peeped). Some is so bad, that i can't get rid of it all, and that's one of the things that scares me about my great desire for the EF 85 f/1.8..and also steered my thoughts from the Tokina 11-16, to the EF-S 10-22.  There's lateral and longitudinal CA. One is easy to correct, the other isn't. "I think the idea of art kills creativity" - Douglas Adams
LOG IN TO REPLY |
wombatHorror Goldmember 1,937 posts Joined Sep 2010 Location: NJ More info | Jan 15, 2012 14:35 | #10 Tanchistu wrote in post #13691618 I know that there are plenty of software solutions that offer CA elimination, and with very good results. But why? What makes CA so easy to correct in digital post processing? all it is is different frequencies of light being bent by different amounts, so they just do a non-linear scaling for the red data and green data and blue data to bring the capture data back as close as they can to if the light had been bent by the same amount for each color
LOG IN TO REPLY |
tonylong ...winded  More info | Jan 15, 2012 14:56 | #11 Yeah, I find that for the widest apertures, the "corrections" will typically be insufficient, you may need to do some work to get the CA where it's not so noticeable. Tony
LOG IN TO REPLY |
Dooms_day Senior Member  509 posts Joined Jan 2009 Location: Maryland, USA More info | Jan 15, 2012 15:22 | #12 |
531JG Member 30 posts Joined Feb 2011 More info | Jan 15, 2012 15:35 | #13 The new CA removal tool in LR4 (Beta) seems to be working quite well so far _______________
LOG IN TO REPLY |
tonylong ...winded More info | Jan 15, 2012 15:48 | #14 531JG wrote in post #13709049 The new CA removal tool in LR4 (Beta) seems to be working quite well so far Hmm, I may need to check it out with some of my shots! The 85L is pretty "notorious" for CA wide open with high-contrast stuff Tony
LOG IN TO REPLY |
S.Horton worship my useful and insightful comments  More info | Jan 15, 2012 15:59 | #15 René Damkot wrote in post #13703516 There's lateral and longitudinal CA. One is easy to correct, the other isn't. https://photography-on-the.net …ight=lateral#post12363904 https://photography-on-the.net …9257&highlight=lateral+ca https://photography-on-the.net …5307&highlight=lateral+ca You really could write a book. Sam - TF Says Ishmael
LOG IN TO REPLY |
 | x 1600 |
| y 1600 |
| Log in Not a member yet?
Register to forums
Registered members may log in to forums and access all the features: full search, image upload, follow forums, own gear list and ratings, likes, more forums, private messaging, thread follow, notifications, own gallery, all settings, view hosted photos, own reviews, see more and do more... and all is free. Don't be a stranger - register now and start posting!
|
| ||
| Latest registered member is JTravLog 966 guests, 138 members online Simultaneous users record so far is 15,144, that happened on Nov 22, 2018 | |||
!
