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Old June 13th, 2015, 08:26 PM   #1
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Strange X70 W/B flaw?

I have been noticing this for a while on both the old and now the new v2.0 f/w.

It has to do with high gain and zoom. The camera picture will turn GREEN at like 85%+ optical zoom. Happens on both presets and AWB settings. Weirdest thing. Just did a slow crawl by crawl zoom in on a dark white area under my desk, and at 85%, the picture just got off colored at 33db, as if I pushed a PP or WB button. Zoomed out, went back to normal. Obviously, the high gain, especially the Clear Image noise, excentuates this, as the black noisy areas being green is quite obvious. This transition would typically change about a second after stopping the zoom on target.

I turned the camera off, and when I turned it back on, I cannot produce the problem. I know it is there, because I have seen it several times, and cannot figure it out. When it turned green on indoor preset, I switched to AWB, and the picture remained the same, which is strange because switching to AWB typically severely changes the hue of the picture.

I will try to post a clip as soon as I can get the problem to repeat.

Paul
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Old June 13th, 2015, 08:49 PM   #2
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Re: Strange X70 W/B flaw?

Here is a YouTube video showing the problem. I boosted the saturation to highlight it, but it is just as plain to see a normal saturation levels. Stepping down to 1/15 or 1/8 shutter to brighten things up seemed to pop the green away. Seems like the camera is adding some sort of additional processing when the levels get very low. Again, this is all in optical zoom, but I am pinning the problem on a DSP fluke.

As I shoot at high gain all the time, night ENG, this is obviously a problem for me. I am loosing faith in Sony products. I know sure as heck I won't be adding 4K to this "green machine" for $500.

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Old June 14th, 2015, 12:01 AM   #3
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Re: Strange X70 W/B flaw?

This looks like night shoot mode.
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Old June 14th, 2015, 01:02 AM   #4
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Re: Strange X70 W/B flaw?

No "green screen" jokes. :)

Paul
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Old June 14th, 2015, 01:51 AM   #5
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Re: Strange X70 W/B flaw?

Yikes!

Last night, I was prepping my X70 for a meeting I shot today. My iris was locked wide open, and shutter locked at 50. The gain was set to auto. I was trying to choose a decent color profile for indoors (based on your corrections, Paul), which is next to impossible with this camera as highlights turn yellow so easily, and gradients have such a terrible harshness to their transitions, even when not blown out, no matter the knee settings. I wound up going with Cinematone 2 as it seemed the "least offensive" to me. On all the cameras I've used, never has getting decent color seemed so insurmountable! For some reason, ITU709, even corrected, seems so very, very yellow on anything warmer than daylight.

Anyway, at one point, I panned between bright and dark areas of the room. The bright reflection of a floor lamp on the wall was really blown out, and the camera did not reduce the gain to compensate for the over-exposure, but remained at +21dB. I zoomed in on the over-exposed reflection so that the entire frame was completely blown out, to no avail. I switched to manual gain, and was able to change the gain fine, but then switched back into auto gain, and the X70 left the gain where I had set it, whether too dark or too bright.

Tried powering the camera off and back on, to no avail.

Finally, I switched the "full auto" button on, and back off. The problem was "fixed," and "auto gain" worked again.

At least I got some good footage at the meeting. The couple things I love about this camera are its fine-grain noise, audio limiting (not as good as Sound Devices, but very usable), and punch-in focus assist. I wish it had three rings, decent colorimetry, and a faster lens to make its large sensor more than a marketing spec.

What was Sony thinking with this camera? Why such a weird way of managing colorimetry, white balance, etc., and such random occurrences of these "flukes"? Wouldn't Sony want to put their best foot forward with such a "new system," or is the X70 just one big public experiment that will soon be forgotten (except by those of us who invested in it)?
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Old June 14th, 2015, 02:36 AM   #6
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Re: Strange X70 W/B flaw?

My ax100 also does not do well at very high gains, I had some weird color-artifacts during a ceremony and it was very visible on the dark blue costumes the groomsmen where wearing, the noise was so obvious it was distracting and I had to use neatvideo on some shots, something I never have to use on any of my other camera's..
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