Tips for Limiting Chromatic abberration at DVinfo.net

Brian Luce · December 2nd, 2007, 07:24 PM

There's a lot of talk of CA, but there isn't a resource that spells out guidelines for preventing CA. Here are some instances that have caused CA for me.

For starters,

1) Avoid shooting through the long end of the lens

2) Avoid shooting with lens wide open

3) Avoid Bright/contrasty backgrounds.

What are some others?

Bill Ravens · December 2nd, 2007, 09:07 PM

there's a few plugins that will remove CA. The one I use works with VirtualDub...not perfect, but, better than no correction.

Brian Luce · December 3rd, 2007, 01:45 AM

Quote:

Originally Posted by Bill Ravens

there's a few plugins that will remove CA. The one I use works with VirtualDub...not perfect, but, better than no correction.

Thanks by I was thinking more along the lines of camera/lens settings. IE avoiding it in the first place.

Tom Hardwick · December 3rd, 2007, 03:04 AM

It sounds to me Bruce as if the fear of CA could be limiting your shooting options somewhat. Shooting wedding guests at the long end of the zoom and at maximum aperture sure does raise the CA levels, but at the same time the flattering perspective, the differential focus and the lack of intimidation gives me the portraits I want.

You might say that you shouldn't shoot at full wide because of the barrel distortion so prevalent in camcorders, but most clients want the perspective shots and won't be looking at the vignetting way up there in the corners.

tom.

Bill Ravens · December 3rd, 2007, 08:23 AM

Brian...

There's not much you can do to reduce CA other than the items you listed. It's a weakness of the lens design. The most effective option, of course, is to change your lens. You may want to consider more fill light to reduce contrast, but, the wedding party might object as it's rather intrusive.

Shai Camerini · December 3rd, 2007, 09:25 AM

what is that anyway?

Tom Hardwick · December 3rd, 2007, 09:35 AM

Chromatic abberation? When not all colours are brought to the same focus point. Jeff explains it well here:

http://www.dvinfo.net/articles/optics/lensdefects.php

Seun Osewa · December 3rd, 2007, 09:38 AM

What's the "long end of the lens"? Is it zoom?

What's "wide open"? Is it the iris setting? ???

Tom Hardwick · December 3rd, 2007, 09:42 AM

The long end is the longer focal lengths. Wide open refers to the iris, yes.

Brian Luce · December 3rd, 2007, 12:23 PM

I've also heard of shooters getting CA at the wide end of the lens, anyone experience this?

Shai Camerini · December 3rd, 2007, 01:10 PM

Thanks Tom

Adam Letch · December 3rd, 2007, 05:58 PM

whether tripod or shoulder, I find if I'm on a tripod I shoot using the flip out LCD, and I use the hoodman on it to reduce glare and solarization. I've found that I've learnt to look out for it, and as such I will pull back the zoom slightly to either get rid of the CA or diminish it.
The EVF you can probably do the same, but either it doesn't resolve enough to see it, or I just haven't observed it yet, as it was only on my last shoot I bothered to pay attention to it.

Roman Schoen · January 25th, 2020, 07:28 AM

Quote:

Originally Posted by Bill Ravens

there's a few plugins that will remove CA. The one I use works with VirtualDub.

I'm searching such a VirtualDub-plug-in to reduce chromatic abberation in post. Has someboy a name of a plug-in?

December 2nd, 2007, 07:24 PM	#1
Brian Luce Inner Circle Join Date: Jan 2006 Posts: 2,290	Tips for Limiting Chromatic abberration There's a lot of talk of CA, but there isn't a resource that spells out guidelines for preventing CA. Here are some instances that have caused CA for me. For starters, 1) Avoid shooting through the long end of the lens 2) Avoid shooting with lens wide open 3) Avoid Bright/contrasty backgrounds. What are some others?

December 3rd, 2007, 09:25 AM	#6
Shai Camerini Regular Crew Join Date: Jun 2006 Location: Israel Posts: 64	can someone post a ca Sample? a Photo or something what is that anyway? __________________ www.cutaway.co.il

December 3rd, 2007, 01:10 PM	#11
Shai Camerini Regular Crew Join Date: Jun 2006 Location: Israel Posts: 64	Thanks Tom __________________ www.cutaway.co.il

December 3rd, 2007, 05:58 PM	#12
Adam Letch Major Player Join Date: Feb 2006 Location: Perth, Western Australia Posts: 414	Depending on how you shoot whether tripod or shoulder, I find if I'm on a tripod I shoot using the flip out LCD, and I use the hoodman on it to reduce glare and solarization. I've found that I've learnt to look out for it, and as such I will pull back the zoom slightly to either get rid of the CA or diminish it. The EVF you can probably do the same, but either it doesn't resolve enough to see it, or I just haven't observed it yet, as it was only on my last shoot I bothered to pay attention to it.

December 2nd, 2007, 09:07 PM	#2
Bill Ravens Join Date: Nov 2001 Location: santa fe, nm Posts: 3,264 Images: 10	there's a few plugins that will remove CA. The one I use works with VirtualDub...not perfect, but, better than no correction.

December 3rd, 2007, 03:04 AM	#4
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	It sounds to me Bruce as if the fear of CA could be limiting your shooting options somewhat. Shooting wedding guests at the long end of the zoom and at maximum aperture sure does raise the CA levels, but at the same time the flattering perspective, the differential focus and the lack of intimidation gives me the portraits I want. You might say that you shouldn't shoot at full wide because of the barrel distortion so prevalent in camcorders, but most clients want the perspective shots and won't be looking at the vignetting way up there in the corners. tom.

December 3rd, 2007, 08:23 AM	#5
Bill Ravens Join Date: Nov 2001 Location: santa fe, nm Posts: 3,264 Images: 10	Brian... There's not much you can do to reduce CA other than the items you listed. It's a weakness of the lens design. The most effective option, of course, is to change your lens. You may want to consider more fill light to reduce contrast, but, the wedding party might object as it's rather intrusive.

December 3rd, 2007, 09:35 AM	#7
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	Chromatic abberation? When not all colours are brought to the same focus point. Jeff explains it well here: http://www.dvinfo.net/articles/optics/lensdefects.php

December 3rd, 2007, 09:38 AM	#8
Seun Osewa Major Player Join Date: Oct 2006 Location: West Africa Posts: 255	What's the "long end of the lens"? Is it zoom? What's "wide open"? Is it the iris setting? ???

December 3rd, 2007, 09:42 AM	#9
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	The long end is the longer focal lengths. Wide open refers to the iris, yes.

December 3rd, 2007, 12:23 PM	#10
Brian Luce Inner Circle Join Date: Jan 2006 Posts: 2,290	I've also heard of shooters getting CA at the wide end of the lens, anyone experience this?