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Author Topic: A7 / A7R problem with DPR Test Scene.  (Read 1513 times)

thierrylegros396

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A7 / A7R problem with DPR Test Scene.
« on: November 22, 2013, 12:05:06 PM »

A7 / A7R problem with DPR Test Scene.

Just see 100% Sample compared with D800 and IQ180.

Artefacts  ??? How is it possible these are so strong (whatever the ISO) and don't occur with the D800.

For lithography shooters, the MF is not dead !

Have a Nice Day.

Thierry
« Last Edit: November 22, 2013, 12:55:42 PM by thierrylegros396 »
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thierrylegros396

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Re: A7 / A7R problem with DPR Test Scene.
« Reply #1 on: November 22, 2013, 01:07:10 PM »

Seems to come from the JPG engine.

Fortunately RAW don't suffer of these artefacts.

As ever, always shoot RAW ;) ;)
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ErikKaffehr

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Re: A7 / A7R problem with DPR Test Scene.
« Reply #2 on: November 22, 2013, 02:51:29 PM »

Hi,

The D800 has OLP filter, that reduces the aliasing artifacts. Additionally the JPEG is smeared out. Comparing with the D800E would be more interesting. The IQ 180 has twice the megapixels, and that certainly helps but the IQ180 has also an unhealthy amount of aliasing. I suspect the image was added just to demonstrate aliasing.

An MFDB like mine P45+ would produce even more aliasing.

You can reduce aliasing by stopping down, so diffraction softens the image.

Best regards
Erik

A7 / A7R problem with DPR Test Scene.

Just see 100% Sample compared with D800 and IQ180.

Artefacts  ??? How is it possible these are so strong (whatever the ISO) and don't occur with the D800.

For lithography shooters, the MF is not dead !

Have a Nice Day.

Thierry
« Last Edit: November 22, 2013, 02:53:33 PM by ErikKaffehr »
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thierrylegros396

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Re: A7 / A7R problem with DPR Test Scene.
« Reply #3 on: November 23, 2013, 06:50:16 AM »

Thanks for the response.


But Alpha 7 is 24.3 megapixel full-frame CMOS sensor with OLPF and has those aliasing artifacts.

The RAW files of the A7/A7R don't exhibit such artifacts, why  ???

Even if IQ180 has twice the pixel count (about 1.41x resolution) it seems to have FAR MORE details and less objectionable aliasing.


Have a Nice day.

Thierry
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ErikKaffehr

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Re: A7 / A7R problem with DPR Test Scene.
« Reply #4 on: November 23, 2013, 07:46:07 AM »

Hi,

My fault!

I was looking at the raw images first ( a couple of days ago ), as I never shoot JPEG. I noticed the rich amount of aliasing and I thought that it was what you were objecting to.

Best regards
Erik

Thanks for the response.


But Alpha 7 is 24.3 megapixel full-frame CMOS sensor with OLPF and has those aliasing artifacts.

The RAW files of the A7/A7R don't exhibit such artifacts, why  ???

Even if IQ180 has twice the pixel count (about 1.41x resolution) it seems to have FAR MORE details and less objectionable aliasing.


Have a Nice day.

Thierry
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