Guy Mcloughlin
Forum Replies Created
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[Stephen Crye] “And in this post, “iSi” includes a screen shot of the same reddish CA on top of the little ornamental architectural object. Now, please understand that this example shows a very minor amount of fringe; what worries me is that it is the same color as what I am seeing in the night lights shots:
https://www.isi-asia.net/download/A-resort-in-Pattaya-ca.jpgI have read (and want to believe) that the AC160 has Chromatic Aberration Compensation (CAC) built in. Adam Wilt of ProvideoCoalition claims that it only works on lateral CA.”
…Looking at this example, I can clearly see what you are talking about. Yes, this looks like CA to me, but it seems like it’s only a problem with over-exposed whites against a darker background. If you plan on doing a lot of night shooting, then I think you may have to by-pass on these Panasonic cameras, but I honestly can’t say which camera brand will perform better under the same conditions. ( i.e. Wide-open Low-light shooting with lots of subject contrast )
I’ve seen the same problems with both Canon and Sony prosumer cameras, and often the longer/faster the lens the worse the CA performance is when shooting wide open.
Even DSLR still photo prime lenses will show objectionable CA when shooting at maximum apertures, but the CA becomes properly controlled once the lens is stopped down a bit.
I would be curious to see if the Panasonic CA problem goes away once the lens is stopped down 1 or 2 stops. ( makes for a very slow lens under low-light conditions, but are there any other options ? )
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Hi Steve,
I don’t think the examples you point to are caused by chromatic aberration.
What you are seeing is light “bloom” which every camera ( including film cameras ) exhibit when shooting high contrast over exposed light sources.
The “red” color comes from filming sodium-vapor street lights, which are partial spectrum sources, and will always look “red”. ( sort of an orangey-red )
Notice that other over exposed light sources ( non sodium vapor lights ) like car headlights, red streetlights, etc… also show “bloom” but not the “red” color of the sodium vapor lights.
My own personal concern with the new Panasonic AC130 / AC160 / HPX250 cameras was lens flare, but after trying the camera out, I found that lens flare is very well controlled. ( much better than the Canon cameras I was using to compare )
Optically, I don’t think you are going to find any real issues with the lens on these new Panasonic cameras. Overall it’s a very good lens.
– Guy
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My understand is that yes, the AF-100 applies image corrections when shooting video with Lumix lenses. ( same goes for the GH-2 camera )
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When you record, do you have the mic channel levels set to zero ?
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I would be cautious if you are not doing the lighting…
1- Make sure the green screen background is properly lit by using the waveform display on your camera/monitor, when viewing just the background the waveform should show a straight thin line right across the image area.
2- Make sure your lighting person has low level edge-lighting on your subjects to guarantee there is no green-screen bleed around the edges of your subject. The test that I always do is to kill everything except the green-screen lighting, then looking at your subject you should see no green bleed or spill on your subject.
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Lots of people have used the AF-100 for green screen work with no problems. As always with green screen filming, how you light and how you expose are the main ingredients to success.
Here are a couple of threads from the DvxUser website on using the AF-100 for green screen work:
Af100 for Green Screen Shooting
Chroma Key Test Footage – Nano vs. AVCCAM
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I’ve heard of one person bricking their GH-2 because they tried to update the firmware with a defective 3rd party battery that died during the updating process.
Bottom Line: Always use a Panasonic battery when updating the firmware.
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For PC users like myself, our NLE software handles offloading with ease…
I use Sony Vegas Pro, so all I have to do is either connect the camera or plug the SD memory card in to a reader, then use the built-in Sony Device Explorer utility that allows me to selectively import individual clips or import them all if I want, and will then automatically transfer full length clips to our hard drives and maintain the AVCHD format.
The CineForm CODEC is very useful, but mainly as an editing CODEC, though you can use it to import clips, and it will automatically detect and remove telecine pull-down encoding that many consumer AVCHD cameras use to store 24p footage.
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The hack only effects video functions, and it’s easy to remove the hack and restore the original firmware.
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Yes, the AC-160 SDI out is only 8-bit, just like the AF-100.
It’s too bad that Panasonic crippled the output this way, which is why I would only consider buying the AC-130 or the HPX-250. For me, the extra features of the AC-160 aren’t worth the price without 10-bit SDI out, so I would rather spend a little bit more and buy the HPX-250, or spend a lot less and buy the AC-130.