Just nasty chromatic aberration or???

David C. Williams · December 16th, 2009, 02:15 AM

The EX lens is actually pretty damn good for the price. Baring the odd faulty one of course.

The correction they talk about is electronic. To do that accurately though, you much have the correction custom mapped for the lens, hence it only works well or at all with their own lenses as they don't want to help sell a competitors.

You can fix it a bit in post by splitting the 3 RGB channels into layers and converging them.

The easiest way to alleviate it is to close the iris some. That way the outer edge of the lens, where it's worst, is not used.

Marty Welk · December 16th, 2009, 02:23 AM

Quote:

Originally Posted by David C. Williams

Some physics lessons (perhaps english as well) will help you understand why it occurs even in multi-million dollar telescopes.

Does the ex-3 have a better lens than these 1 models? the stills your showing on your website dont seem to be comming apart.
because i could go with a 3 over the 1 if that was one of the "improvements" ?

Marty Welk · December 16th, 2009, 02:30 AM

Quote:

Originally Posted by David C. Williams

The correction they talk about is electronic. To do that accurately though, you much have the correction custom mapped for the lens, hence it only works well or at all with their own lenses as they don't want to help sell a competitors.
.

ahh, so they prime the camera for the deficiencies of the lenses, knowing which lens is going to be on it. that is what i was thinking they might be doing.
myself i am happy to stick with One lens item. besides the fact that i cant afford more lenses, i usually get away with one and adjust everything else.

Brian Luce · December 16th, 2009, 04:54 AM

Quote:

Originally Posted by Marty Welk

Does the ex-3 have a better lens than these 1 models? the stills your showing on your website dont seem to be comming apart.
because i could go with a 3 over the 1 if that was one of the "improvements" ?

The Ex3 uses the exact same lens. But, you can take it off and put something expensive on it, but be prepared for major sticker shock, not to mention there isn't a big selection of 1/2" lenses. You can go with a bigger lens, but then you get a cropping effect.

Btw, it looks like CA to me. You're at extreme tele, hi contrast subject, that's when you get it. Thing is, you cannot expect a perfect picture from a 6,000 dollar camera. If it *did* give you a perfect picture, then there'd be no reason to spend $150,000 on a F20. There's still that get what you pay for thing.

Alister Chapman · December 16th, 2009, 05:39 AM

Even top end HD lenses produce some CA. Generally speaking the sharper you make a lens the more CA it will produce. It can be minimized through the use of combinations of very exotic types of glass, grown under high pressure from crystals but this makes the lenses extremely expensive. That's why cameras like the PDW-700 and F800 now have automatic CA correction called ALAC. ALAC only works with certain lenses that have a digital interface to talk to the camera. The new PMW-350 also has ALAC which works with the kit lens or with 3rd party lenses that support ALAC. ALAC will not work with an EX3 as far as I know, only with the stock EX3 lens or the EX3 wide lens.

Thierry Humeau · December 16th, 2009, 07:28 AM

And ALAC does not provide 100% cure to CA. It definetely minimizes it but not completely suppresses it.

T.

Marty Welk · December 16th, 2009, 07:58 AM

thanks for more info (everyone)
i looked up a tech overview of the lesser sony cameras, and this color slop job was some 4 Pixels (one direction) offset on the edges , and the tech was using a Mid Zoom.

4 pixels offset is 2 pixels in "SD" (one direction) for those (cheaper) cameras, now i will have to look at my sd junk and see if the color has ever been that far off.

Olof Ekbergh · December 16th, 2009, 08:23 AM

Even $30,000.00 + lenses have some CA. It is not really possible to make a CA free fast zoom lens at a reasonable cost.

I did not post that frame with red CA to criticize the lens on the EX cams, just to show that it does happen, and the cause is: Zoomed all the way in, iris open all the way, very contrasty subject.

Knowing this is the case, you can compensate when you recognize those conditions. I see the same thing in my Canon L still lenses under the same conditions.

I think the EX series lenses are very good for the price. The sweet spot seems to be f4 even zoomed in all the way.

That is my nickels worth.

David Issko · December 16th, 2009, 01:39 PM

I can see that my Ex3 and XS lens combo has some CA in extreme LHS. No one else other than another pro shooter or probably an editor would notice it.

December 16th, 2009, 02:15 AM	#16
David C. Williams Major Player Join Date: Jun 2008 Location: melb.vic.au Posts: 447	The EX lens is actually pretty damn good for the price. Baring the odd faulty one of course. The correction they talk about is electronic. To do that accurately though, you much have the correction custom mapped for the lens, hence it only works well or at all with their own lenses as they don't want to help sell a competitors. You can fix it a bit in post by splitting the 3 RGB channels into layers and converging them. The easiest way to alleviate it is to close the iris some. That way the outer edge of the lens, where it's worst, is not used. __________________ www.davidwilliams.com.au

December 16th, 2009, 05:39 AM	#20
Alister Chapman Inner Circle Join Date: Dec 2005 Location: Bracknell, Berkshire, UK Posts: 4,957	Even top end HD lenses produce some CA. Generally speaking the sharper you make a lens the more CA it will produce. It can be minimized through the use of combinations of very exotic types of glass, grown under high pressure from crystals but this makes the lenses extremely expensive. That's why cameras like the PDW-700 and F800 now have automatic CA correction called ALAC. ALAC only works with certain lenses that have a digital interface to talk to the camera. The new PMW-350 also has ALAC which works with the kit lens or with 3rd party lenses that support ALAC. ALAC will not work with an EX3 as far as I know, only with the stock EX3 lens or the EX3 wide lens. __________________ Alister Chapman, Film-Maker/Stormchaser http://www.xdcam-user.com/alisters-blog/ My XDCAM site and blog. http://www.hurricane-rig.com

December 16th, 2009, 07:28 AM	#21
Thierry Humeau Telecam Films Join Date: Apr 2006 Location: Washington DC Posts: 723	And ALAC does not provide 100% cure to CA. It definetely minimizes it but not completely suppresses it. T. __________________ Thierry Humeau, DoP Télécam Films www.telecamfilms.com

December 16th, 2009, 01:39 PM	#24
David Issko Major Player Join Date: Jul 2008 Location: Melbourne, Australia Posts: 393	I can see that my Ex3 and XS lens combo has some CA in extreme LHS. No one else other than another pro shooter or probably an editor would notice it. __________________ David Issko Edit 1 Video Productions

December 16th, 2009, 07:58 AM	#22
Marty Welk Major Player Join Date: Sep 2008 Location: East Bay Cali Posts: 563	thanks for more info (everyone) i looked up a tech overview of the lesser sony cameras, and this color slop job was some 4 Pixels (one direction) offset on the edges , and the tech was using a Mid Zoom. 4 pixels offset is 2 pixels in "SD" (one direction) for those (cheaper) cameras, now i will have to look at my sd junk and see if the color has ever been that far off.

December 16th, 2009, 08:23 AM	#23
Olof Ekbergh Sponsor: Westside AV Join Date: Dec 2008 Location: Mount Washington Valley, NH, USA Posts: 1,365	Even $30,000.00 + lenses have some CA. It is not really possible to make a CA free fast zoom lens at a reasonable cost. I did not post that frame with red CA to criticize the lens on the EX cams, just to show that it does happen, and the cause is: Zoomed all the way in, iris open all the way, very contrasty subject. Knowing this is the case, you can compensate when you recognize those conditions. I see the same thing in my Canon L still lenses under the same conditions. I think the EX series lenses are very good for the price. The sweet spot seems to be f4 even zoomed in all the way. That is my nickels worth.