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Author Topic: Sony A99 and GH3 moire and aliasing?  (Read 6832 times)

tjbates

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Sony A99 and GH3 moire and aliasing?
« on: October 04, 2012, 04:50:43 pm »

I was wondering now that a Sony A99 is currently in the house of Lula, if Chris Sanderson or Michael Reichmann could give us a video mode analysis of Sony's new full frame offering including thoughts on the XLR audio accessory and the extent of moire and aliasing issues.

The Panasonic GH3 is also a camera hopefully worthy of a stills/ video review.
I remember reading Michael's excellent review and follow up of the GH2 and how enthusiastic he was about it's unique abilities. As it turns out - the GH2 is still unique (4 full years after the "DSLR" craze started) in that it is the only "DSLR" style camera that is able to produce moire and aliasing free video. The Canon 5DMK3 is relatively free of these ailments but the video resolution is widely reported to be far below the GH2 even without a firmware hack.

The rumour, or rather currently limited hard evidence, is that the Sony A99 and the new GH3 suffer from a certain degree of moire and aliasing issues.
I wish to humbly request that someone with authority (Chris or Michael) when the opportunity arises, confirm or deny. Many thanks!

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ErikKaffehr

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Re: Sony A99 and GH3 moire and aliasing?
« Reply #1 on: October 09, 2012, 02:21:13 am »

Hi,

A77 has issues with Moiré. A99 probably, too.

The problem with DSLRs is that the AA-filter is not dimensioned for motion video, but for sensor resolution. It's hard to filter out moiré in software. A 2MP DSLR with proper OLP filtering would give better HDvideo than a 24MP DSLR sampled down to 2MP. HD video is 2MP.

I guess that more could be done in the ASICs. To handle downscaling you need to apply gaussian blur before downsampling and sharpen the downsampled image. I don't think this is properly handled in most of the DSLR ASICs.

4K or 8K video from a DSLR would probably be quite nice!

See sample from A77 video below.

Best regards
Erik

I was wondering now that a Sony A99 is currently in the house of Lula, if Chris Sanderson or Michael Reichmann could give us a video mode analysis of Sony's new full frame offering including thoughts on the XLR audio accessory and the extent of moire and aliasing issues.

The Panasonic GH3 is also a camera hopefully worthy of a stills/ video review.
I remember reading Michael's excellent review and follow up of the GH2 and how enthusiastic he was about it's unique abilities. As it turns out - the GH2 is still unique (4 full years after the "DSLR" craze started) in that it is the only "DSLR" style camera that is able to produce moire and aliasing free video. The Canon 5DMK3 is relatively free of these ailments but the video resolution is widely reported to be far below the GH2 even without a firmware hack.

The rumour, or rather currently limited hard evidence, is that the Sony A99 and the new GH3 suffer from a certain degree of moire and aliasing issues.
I wish to humbly request that someone with authority (Chris or Michael) when the opportunity arises, confirm or deny. Many thanks!


« Last Edit: October 09, 2012, 02:23:52 am by ErikKaffehr »
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Erik Kaffehr
 

michael

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Re: Sony A99 and GH3 moire and aliasing?
« Reply #2 on: October 09, 2012, 09:21:55 am »

The A99 shows moire and artifacting. A BBC cinematographer did some testing the other day and confirms this.

To my knowledge there are no GH3's available yet for testing, so I'd be surprised if anyone yet knows how the camera does in this regard. I expect to have one in house before the end of the month and we'll see.

Michael


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RFPhotography

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Re: Sony A99 and GH3 moire and aliasing?
« Reply #3 on: October 13, 2012, 10:38:22 pm »

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