1 FPS Timelpase, Galaxy Of Hot Pixels and Sensor Calibration Times

[Miltos Pilalitos]

A few hours ago I shot a couple of night exterior Time-lapse shots with the EPIC. FPS and shutter were both at 1fps.

While on location, everything was looking good on the LCD screen but when I viewed the footage later on RCX, hundreds of hot pixels where visible. In fact, there were so many that the footage is rather unusable! Fortunately, it was only a test so we didn't have any heart attacks. Nevertheless, I was surprised by the obviousness of the problem. It's been a while since the last time I shot a time-lapse with the RED ONE and I was under the impression that RCX somehow masked the hot pixels when in Full De-bayer mode but certainly this is not the case.

So, the only solution is Sensor Calibration at the time-lapse's settings. After the calibration's 20 minutes (I almost emptied a fully charged REDVOLT doing it!!!) the hot pixels disappeared and the camera was ready to shoot nice clean 1 fps Time-lapse. The question now is... what does the 1fps Sensor Calibration do to the image if we go back to normal shooting settings like 24 Fps, 1/48th? The first thing I noticed from a very fast test was that some of the hot pixels where now appearing as black when the subject was overexposed (clipped whites). This is almost a deal breaker in many scenarios so that means a new Sensor Calibration is required for the new settings.

I am not sure why the EPIC takes so much time to do the Sensor Calibration but it can certainly be an issue if you are planning to shoot Night Time-lapses as part of a bigger shooting day. The Sensor Calibration times from one setting to the other will kill even the most patient crew! Maybe two EPIC bodies would save the day. :D

Something to keep in mind then.

[David Battistella]

Miltos,

Shoot the TL footage on the user setting and then shoot the 24fps with the EPIC default calibration.

You actually get two calibrations.

The default
The user FPS calibration.

David

[Miltos Pilalitos]

Thanks David. What if the factory settings are not matching the ones we are using for our project? Is it manually calibrated also?

[David Battistella]

I believe you only get one manual calibration.

It would be nice to store two or three.

I think the calibration time might be a bit longer due to larger sensor size, HDRX,but I'm just guessing. There is more going on than in the r1. That is for sure.

David

[Mike Lary]

The Sensor Calibration times from one setting to the other will kill even the most patient crew! Maybe two EPIC bodies would save the day. :D

Hi Miltos,

It's my understanding that, starting in firmware version 2.05, user-defined black shading calibrations are stored as presets for later use (they'll be auto-selected when you go back to those same camera settings). In theory, as long as you don't have big ambient temperature changes, you could black shade for each anticipated frame rate and then switch between them during production. Once you update the firmware, however, the presets will be gone. That's my understanding based on a conversation with support, but I haven't tested it yet.

BTW, here's the official word from Deanan on when to perform black shading.

My recommendation is to blackshade:
1) upgrading to new firmware
2) big ambient temperature changes
3) long exposure times (longer than ~1/15th sec)
4) very short exposure times (shorter than around ~1/1000th)
5) beginning of a project
6) as often as you feel like

Remember to black shade at default after long/short exposure black shade when your finished.

More convenient/flexible black shading coming later.

Here's the original thread:
http://173.199.159.58/forum/showthre...en-shoot/page5

[Nils Ruinet]

Could someone at Red please confirm this (regarding storing more than one black cal in build 2.0.5) ? I also noticed the hot pixels in long exposure mode, and doing a black cal takes a loooong time when the light is moving and you need to get shooting.
I think Jarred mentionned there would be an option to memorize different black calibrations at various settings, but I didn't hear anything about it being implemented in 2.0.5...

Out of curiosity, does anyone know why black cal takes so long ? I think it was much faster on the Red One.

[David Battistella]

I'm running 2.0.5

Went through this two nights ago.

1 user calibration
1 default

That's it under this build.

Tested by me.

David

[Deanan]

I'm running 2.0.5

Went through this two nights ago.

1 user calibration
1 default

That's it under this build.

Tested by me.

David

Correct, two cal slots are currently available.

[Nils Ruinet]

Correct, two cal slots are currently available.

So that means you can store 2 different calibrations (for example one at 1/50 shutter and one at 1s shutter) and then switch between them as needed without having to go through the cal process again every time ?

[David Battistella]

I take it to mean

1 slot for default (because you need a default)
1 slot for user program