Minimizing CA at DVinfo.net

Eugene Kosarovich · July 7th, 2008, 09:49 PM

I'm happy with my F335 camcorder and my Canon KH20x6.4-KRS HDgc lens. But...

There definitely is some CA with the lens. Though it is still less than what I found when I experimented with a Canon SD lens on this camera, it was definitely there in some of my HD I've been shooting recently. Others have pointed out their CA issues in this forum as well with numerous lenses.

Then in this week's TV Technology, they had a great story about economical HD lenses, and there's this great quote from Fujinon about economical HD lenses: "They were designed for TV applications, where artifacts like chromatic aberration, and edge softening aren't as problematic."

So my question is, since all affordable HD zoom lenses seem to have CA issues, one way or another, what can we do to minimize them?

Is there any kind of guideline for a sweetspot to avoid it? Such as staying between f/4 and f/8? Or are there particular focal lengths worse to show CA more than others, such as full wide?

Thanks.

Steve Phillipps · July 8th, 2008, 01:41 AM

I think keeping you exposure down helps as the bright areas are not so extreme then so the CA effect is lessened. Knocking down the whites below peak level is a good idea regardless of CA. You'll then end up with slightly dark shadow and mid-tone areas but you then bring these up in post. Also in post there are features for reducing CA, you point to the area where it is and de-saturate that colour I believe (not an editor myself).
Steve

Alister Chapman · July 8th, 2008, 07:14 AM

Using ND filters ahead of the lens as opposed to the built in ND can help as it reduces internal lens reflections and flare. The CA will still be there but may not be so pronounced.

July 7th, 2008, 09:49 PM	#1
Eugene Kosarovich Taken away too young... rest in peace Eugene Join Date: Mar 2008 Location: Albany, NY Posts: 161	Minimizing CA I'm happy with my F335 camcorder and my Canon KH20x6.4-KRS HDgc lens. But... There definitely is some CA with the lens. Though it is still less than what I found when I experimented with a Canon SD lens on this camera, it was definitely there in some of my HD I've been shooting recently. Others have pointed out their CA issues in this forum as well with numerous lenses. Then in this week's TV Technology, they had a great story about economical HD lenses, and there's this great quote from Fujinon about economical HD lenses: "They were designed for TV applications, where artifacts like chromatic aberration, and edge softening aren't as problematic." So my question is, since all affordable HD zoom lenses seem to have CA issues, one way or another, what can we do to minimize them? Is there any kind of guideline for a sweetspot to avoid it? Such as staying between f/4 and f/8? Or are there particular focal lengths worse to show CA more than others, such as full wide? Thanks. __________________ Scorpio Productions PDW-F335, PDW-U1, Vegas Pro 9.0b

July 8th, 2008, 07:14 AM	#3
Alister Chapman Inner Circle Join Date: Dec 2005 Location: Bracknell, Berkshire, UK Posts: 4,957	Using ND filters ahead of the lens as opposed to the built in ND can help as it reduces internal lens reflections and flare. The CA will still be there but may not be so pronounced. __________________ Alister Chapman, Film-Maker/Stormchaser http://www.xdcam-user.com/alisters-blog/ My XDCAM site and blog. http://www.hurricane-rig.com

July 8th, 2008, 01:41 AM	#2
Steve Phillipps Inner Circle Join Date: Apr 2006 Location: Wales Posts: 2,130	I think keeping you exposure down helps as the bright areas are not so extreme then so the CA effect is lessened. Knocking down the whites below peak level is a good idea regardless of CA. You'll then end up with slightly dark shadow and mid-tone areas but you then bring these up in post. Also in post there are features for reducing CA, you point to the area where it is and de-saturate that colour I believe (not an editor myself). Steve