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10-24-2020, 01:18 AM   #1
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Live view (HDMI out) ISO to bypass Video ISO limitations?

Hi all,

I was just wondering if any K-1 users have experience using the HDMI out function of the camera to bypass the video ISO limitations which is maxed at 25600.

For example using the liveview at 51200 ISO then using HDMI out to an external recorder, essentially creating a video file shot with 51200 ISO. Does this work in theory and in practice? Because if it does... this is essentially a workaround which will convert the K-1 into a formidable high ISO videography tool. I could imagine putting on some super fast glass and shooting real time night sky videography like this.

Would love input from our forum experts!

Cheers

10-24-2020, 06:23 AM   #2
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I know earlier, but past use of the 645z in this manner proved to be a dismal failure. The hdmi output was not close to the actual sensor data. I have no clue if the k-1 is similar or if your approach could work.

Last edited by UncleVanya; 10-24-2020 at 11:51 AM.
10-24-2020, 08:35 AM   #3
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You're still using the same sensor and the sensor is what limits the usability of the image. This might be a work around to setting the ISO for camera use, but it's quite questionable if it's worth the effort. Similar results (or better) could be achieved by shooting at the highest setable ISO and boosting that in post processing, assuming the super-high ISO image is worth using. Noise becomes a major factor as the ISO is increased since all you're doing is applying amplification to the lowered output signal present at the sensor.
10-24-2020, 11:48 AM - 1 Like   #4
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QuoteOriginally posted by someasiancameraguy Quote
I was just wondering if any K-1 users have experience using the HDMI out function of the camera to bypass the video ISO limitations which is maxed at 25600.
I don't know how that might work, but can tell you that the HDMI out is merely a feed off the rear LCD display. Pentax cameras don't support clean HDMI out.


Steve

10-24-2020, 11:50 AM   #5
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QuoteOriginally posted by stevebrot Quote
I don't know how that might work, but can tell you that the HDMI out is merely a feed off the rear LCD display. Pentax cameras don't support clean HDMI out.


Steve
Exactly my point about the 645z testing that was done using this method.
10-25-2020, 07:34 AM   #6
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QuoteOriginally posted by UncleVanya Quote
Exactly my point about the 645z testing that was done using this method.
I'm aware that the HDMI simply outputs the same thing seen on the LCD, hence all info panels, focus peaking, and what not elements have to be turned off.

Still if the live view feed to the LCD is actually running the sensor at the stated ISO then its possible to record video beyond 25600. It's going to be noisy as hell, but for night sky levels of darkness I'd rather have a working option than not.
10-25-2020, 07:37 AM   #7
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QuoteOriginally posted by someasiancameraguy Quote
I'm aware that the HDMI simply outputs the same thing seen on the LCD, hence all info panels, focus peaking, and what not elements have to be turned off.

Still if the live view feed to the LCD is actually running the sensor at the stated ISO then its possible to record video beyond 25600. It's going to be noisy as hell, but for night sky levels of darkness I'd rather have a working option than not.
It wasn't just the info, the video quality was not the same. I wish I could find the article to have you read it. I'll keep looking.
10-25-2020, 08:48 AM   #8
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QuoteOriginally posted by someasiancameraguy Quote
Still if the live view feed to the LCD is actually running the sensor at the stated ISO then its possible to record video beyond 25600. It's going to be noisy as hell, but for night sky levels of darkness I'd rather have a working option than not.
I am pretty sure that the resolution is downsampled to that of the rear LCD (~1Mpx), but perhaps not. Good luck.


Steve

(...scurrying to see just what it does on the oh-so-similar K-3...)

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