chromatic aberration on a new EX3
Hi everyone,
I am experiencing severe chromatic aberration on my new EX3, especially when zoomed in fully. I am not sure if this is normal - kind of feel that it is more that acceptable. It is most visble in high contrast areas, i.e. a patch of snow on a dark roof. Posted a framegrab here: http://abaku.net/test/Chromatic_Aber...EX3_Test_1.jpg Does anyone have any information about this? regards Oliver |
Welcome to HD, it's pretty much universal even on a £35,000 Canon HJ40! I suppose there could be some sample variation and you could have a particularly bad one.
Steve |
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What F stop were you at. That image looks kind of soft, as though you are wide open in which case you will get some bad aberrations. Try to stay between F8 and F4
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I just experienced something similar. I was shooting scenics and most all footage was OK except for one where I was 90 degrees from sun, fully zoomed in, at @ 4F stop.
Notice the red line on horizon and telephone poll. I just sold my Canon XL-H1 and never had this issue. Is this normal for EX1? What is the fix? |
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I looked at the still now, and to me I must say it looks pretty much par for the course with HD lenses, that's more or less what I've seen on lenses ranging from £5000 to £35000! Though some are less bad than others. Steve |
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I had the problem with a 730 HDCAM with an non HD lens but then it was most apparent when shooting wide with a focal length of 4.5. I was not terribly surprised then, but zoomed in, using only the center part of the lens I did not expect this problem, at least not this much. Is there any adjustments I can make to avoid or reduce this flaw? |
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I wonder if there is a usable filter that will reduce this problem? |
Don't think a filter will help but you can get rid of it pretty well in post. Just pick that colour and de-saturate it (or something like that, I know I've seen my editors do it!)
Steve |
Steve: While CA in itself is constant whatever the aperture if the lens is wide open or stopped down too far the overall image gets softer or slightly blurred, including the CA which makes the CA spread more. Image a completely sharp in focus line that is 2 pixels wide, well if it is soft or out of focus it may be 4 pixels wide, the same happens to the CA, so CA can become more apparent. CA is also dependent on the focal length of a zoom lens. Filters can make the situation worse as they add a further uncorrected (for CA) glass element.
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I have the same experience zoomed in all the way on my Ex-1 on high contrast edges. Looked pretty bad to me so i try to avoid it. I've been told that you get it on many cameras, but i never noticed it as badly. I think its just part of the package for that price.
Lenny |
Leonard, as I said, I've seen it pretty bad on a £35,000 Canon HJ40, and have seen it on just about every single HD lens I've looked at, so it's not just because the EX lens is "budget" priced. It seems it's an HD disease.
I've never tried the likes of Cooke S4s, or Zeiss primes etc., I wonder if they're totally free of it? Steve |
Yes, that's fairly common. A couple things I learned when I was first confronted by the CA problem.
Avoid going wide open at full telephoto. As was mentioned, try to stay between F4 and F8. High contrast areas outdoors with the sun high in the sky will often give a blue line to the right side of the object. I found a site that discussed HD lens design. One of the key points I took away from that article was that the higher a lens' resolving power, the more difficult it is to tame CA. CA is also more difficult to manage on a 3 chip design due to the prism block involved. -gb- |
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