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Old December 19th, 2010, 11:25 AM   #1
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Does the AF-100 Line skip?

Need to know more before considering a purchase.
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Old December 19th, 2010, 12:02 PM   #2
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Why does that matter if the output is good?
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Old December 19th, 2010, 01:32 PM   #3
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It does not appear to. But neither do the GH1 or GH2.
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Old December 19th, 2010, 01:56 PM   #4
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Originally Posted by Don Miller View Post
Why does that matter if the output is good?
From what I've seen so far my Sony EX1 seems to make a better picture. My suspicion is line skipping and some have mentioned that it does. For me it's about quality in gives you a chance for quality out.
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Old December 19th, 2010, 02:01 PM   #5
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Originally Posted by Perrone Ford View Post
It does not appear to. But neither do the GH1 or GH2.
Some say the GH1 and GH2 do line skip?
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Old December 19th, 2010, 02:59 PM   #6
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We see none of the aliasing and moire usually associated with line skipping in the AF100 footage. Looks pretty darn good to me.
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Old December 20th, 2010, 06:55 PM   #7
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there is no line skipping being used. It uses an optical low-pass filter to resolve the aliasing and moire that is typical from high count imagers.

Best,

Jan
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Last edited by Jan Crittenden Livingston; December 21st, 2010 at 07:11 AM.
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Old December 21st, 2010, 04:29 AM   #8
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Thanks Jan. Could you also confirm the size of the sensor IE a 16:9 slice taken from a 17.3 x 13mm sensor?

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Old December 21st, 2010, 07:10 AM   #9
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Thanks Jan. Could you also confirm the size of the sensor IE a 16:9 slice taken from a 17.3 x 13mm sensor?
Actually the 4/3's sensor is a little larger than 17.3mm but what is used in the still cameras is that size, 17.3 X 13mm. When the engineers designed the AF100, they decided to use a little wider on the chip to maximize the height measurement as well, so the image size of the AF100 is 17.8 X 10mm. This gives approximately 12.4 million pixels to work with.

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Old December 21st, 2010, 09:11 AM   #10
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Thanks Jan

All questions answerd Sounds really good now!

Mark
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Old December 22nd, 2010, 12:33 AM   #11
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Perfect Jan.

Thank you

Grazie
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Old December 22nd, 2010, 04:38 AM   #12
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Quote:
Originally Posted by Jan Crittenden Livingston View Post
there is no line skipping being used. It uses an optical low-pass filter to resolve the aliasing and moire that is typical from high count imagers.
My understanding is that the OLPF is arranged to cut off the detail at around the detail level of an HD image - far less than the finer detail of the native chip.

There is no question that the OLPF will largely resolve the issues of moire/aliasing (it will), but this is quite independent of whether the chip is read in total or via line or pixel skipping. Saying that it uses an OLPF, and has little evident moire/aliasing, says little about how the chip is read.

The AF101 is reckoned to have about the same native sensitivity as a 1/2" 3 chip camera, with comparable technology. If every photosite was being read, every frame, the expectation would be that the sensitivity would be (should be) much higher. Technically, the AF101 results are in line with not every photosite being read or used in every frame readout - line skipping or pixel skipping.

If what is basically a still camera sensor is used, the alternative to line or pixel skipping is to read out the entire sensor (all 12.4 million pixels) every frame, deBayer, then downresolve with software filtering. The technical challenge of doing such in terms of complexity, power requirements, heat dissipation etc shouldn't be underestimated, and it is extremely difficult to see how they are overcome in a camera of this price, consuming relatively little power? From a designers point of view, far easier, sensible and more cost effective to pixel skip and deal with the aliasing with an OLPF.

If "line skipping" isn't used, what about other forms of pixel skipping, such as in blocks of four? It would be interesting to point the GH2 at a zone plate in 40fps burst mode, and see what the patterns reveal. That mode restricts resolution to 4 megapixels, and is likely to use the same principles that the AF101 does - but since the GH2 doesn't have the OLPF of the AF101, the alias patterns should be unaffected and tell us more about exactly what's going on.
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Old December 22nd, 2010, 08:54 AM   #13
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So it's clear now it does line skip.... Difficult to see how a camera like this wouldn't.... I have to wonder now about other decisions made in its construction and design and possibly if this was why it has an 8 instead of 10 bit out and how image quality is affected if a Ki Pro is used, and then undergoes a lot of post colour correction for example.
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Old December 22nd, 2010, 09:43 AM   #14
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David

Panasonic GH2 1:1 Mode Revealed

ETC Which shows you don't need to line skip?
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Old December 22nd, 2010, 11:12 AM   #15
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Wide angle for GH2 in Video Mode?

Sorry, I'm a bit lost! Which micro 4:3 (m4/3) focal length should one have to achieve a wide angle view on a GH2, in video mode? By 'wide angle' I mean an angle of acceptance similar to that of a 35mm or 28mm lens on full frame stills 35mm.
In fact I'm so confused that maybe this post should have gone in the GH2 thread; except I want to use the GH2 I just ordered, alongside the AF 100/1 that I have just ordered. (Rush of blood to head.)

And is my old Nikkor 50mm only good for C.U.s of the Sea of Tranquillity? (On the Moon.)
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