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Author Topic: Sony a7r and moire  (Read 1986 times)

AS1

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Sony a7r and moire
« on: September 07, 2014, 03:56:10 PM »

I've been testing the Sony a7r with a Canon 24mmTS lens and while it's definitely very sharp, I get moire in almost every shot...somewhere..! Obviously the lack of AA filter is causing this, but I'm surprised at how often I'm seeing it.
I shoot a lot of interiors, architecture, still life so there's a lot of stuff "sharp" in the photo.
Is anyone else finding this?
I know LR 5 has a nice moire removal tool (and C1) but I'm reluctant to have this extra step of post production in a lot of shots.
Anyone else have any experience with this?
Thanks,
Alan.
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Jim Kasson

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Re: Sony a7r and moire
« Reply #1 on: September 07, 2014, 06:23:17 PM »

I've been testing the Sony a7r with a Canon 24mmTS lens and while it's definitely very sharp, I get moire in almost every shot...somewhere..! Obviously the lack of AA filter is causing this, but I'm surprised at how often I'm seeing it.
I shoot a lot of interiors, architecture, still life so there's a lot of stuff "sharp" in the photo.
I know LR 5 has a nice moire removal tool (and C1) but I'm reluctant to have this extra step of post production in a lot of shots.
Anyone else have any experience with this?

It's the downside of an sensor with no AA filter, even one with under 5um pixel pitch.

In a sensor with a Bayer color filter array, you often see false color, too. Here's an a7R example: http://blog.kasson.com/?p=4750

With a camera that exposes the red, green, and blue parts of a pixel at the same physical location, you still get moire, but no false color: http://blog.kasson.com/?p=4799

You see it in the D800E and D810, too: http://blog.kasson.com/?p=6690

Even an AA filter won't eliminate all moire. Here's an example with the a7: http://blog.kasson.com/?p=4808

Jim

Guillermo Luijk

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Re: Sony a7r and moire
« Reply #2 on: September 08, 2014, 06:23:06 PM »

Some samples would be welcome.
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AS1

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Re: Sony a7r and moire
« Reply #3 on: September 09, 2014, 11:11:49 PM »

Some samples would be welcome.

Guillermo,
That makes sense; I'm traveling at the moment but when I get back I'll post something..
Alan.
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ErikKaffehr

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Re: Sony a7r and moire
« Reply #4 on: September 10, 2014, 01:20:52 AM »

Hi,

It is something like that on my Hasselblad 555/P45+, too. If you work proper with an OLP filter less camera and very good lenses you will get moiré.

Stopping down to f/16 (on the P45+) or possibly f/11 on the A7r gets rid of moiré by reducing fine detail sharpness.

My feeling is that the OLP filters are mostly intended to reduce colour moiré. I can also add that I have seen colour moiré even on my 3.9 micron sensor Alpha 77. So, as Jim says, it doesn't solve all problems.

The lack of OLP filter is one of the reasons I didn't go for the A7r… The others were that I felt the sensor lacked some desirable features like first electronic curtain and on chip phase detection for AF. Features my Alpha 99 has.

Some samples in this article: http://echophoto.dnsalias.net/ekr/index.php/photoarticles/78-aliasing-and-supersampling-why-small-pixels-are-good

Best regards
Erik

I've been testing the Sony a7r with a Canon 24mmTS lens and while it's definitely very sharp, I get moire in almost every shot...somewhere..! Obviously the lack of AA filter is causing this, but I'm surprised at how often I'm seeing it.
I shoot a lot of interiors, architecture, still life so there's a lot of stuff "sharp" in the photo.
Is anyone else finding this?
I know LR 5 has a nice moire removal tool (and C1) but I'm reluctant to have this extra step of post production in a lot of shots.
Anyone else have any experience with this?
Thanks,
Alan.

« Last Edit: September 10, 2014, 01:27:23 AM by ErikKaffehr »
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