Excessive Noise on Epic Green Screen shoot

[Brook Willard]

Daily black shading is insane.

 

[Deanan]

Daily black shading is insane.

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.

 

[benedictspence]

Thank you all for your help in this... I've narrowed it down a bit to the gain settings too; just got to figure out where this happened as the camera should have been reset before it went out.

Mega thanks for the forum and the nice people who frequent it!

 

[ericyoung]

Daily black shading is insane.

Have to admit on Red MX I only ever black shaded on the beginning of projects, firmware changes, BIG ambient temp changes, as I found the black calibration to be extremely stable. Only recently started shooting Epic and been daily black shading because of noise issue at higher frame rates as a precaution.

Glad Deanan has finally given us an official recommendation though!

 

[Robert Hart]

As risk of having my head put on a stick for treasonous sedition or some other perceived offence of envoking an alien camera name, over here in the west ( Australia ) we who drive the SI2K, frequently "Set Blacks" (DVR 1) or "Black Calibrate" (DVR 2) as a form of best practice, always after a reboot and as often as conveniently able otherwise. My understanding is that we need to do this to eliminate a fixed pattern artifact and map defective pixels, not the random pinpoints of noise generated in the sensor.

The Red camera family may have some form of Peltier temp regulator for all I know but camera temps can be a tidal thing. With fan speeds reducing for takes and increasing after buttoning off, after a series of long takes, the temps are going to be higher in cycles, not constant.

In hot environments, it is not unusual for our cameras to report a 25 degree temperature swing after an intense run of takes. As I understand things and I may be wrong, this temp is being reported from the processor enclosure and to keep us mindful of not roasting the CPU or the power supply board. The fluctuations at the camera head should be less as it is cooled only by passive heatsinking through the metal enclosure. Fluctuations there will still happen and a temp rise in the metalwork will dissipate more slowly. The SI2K sensor, unlike the RED camera family is in a separate metal enclosure which is is either docked in a recorder body like ours or runs wild and free on a set of rods and a cable tether to a macbook or whatever.

I like the notion of the sensor panel in the Red camera family being in the active cooling zone. That said, I would not be surprised if sensor temps are more tidal unless there is a solid metal mass intervening in there somewhere. This might explain the designed gradual increase in fans speeds compared to the more brutal slow and fast of our SI2Ks.

Whatever the methods of cooling, conductive paths and the like, sensors are affected by heat, the hotter the noisier I am told.

My personal preference, whether the camera is robust enough to tolerate higher temperatures or not, is to manage as best I can to keep those temperatures down. This is as much to preserve the working life of the electronics as to avoid sensor noise. For a rental camera, life preservation may not be a consideration except, that on your watch, the camera which might have been teetering on the edge, finally steps over on a hot day.

I often set the blacks as a form of proactive insurance. Whether fixed pattern artifacts right on the very threshold of appearing can locally accentuate random sensor noise as an additive component is another matter that only the scientists and techs can tell us for sure. I like to think that frequent setting of the blacks might just give us that little extra margin of suppression.

Outdoors, temp management means a brollie over the camera to keep the sun off and it is not a bad thing for the operator's comfort either. At a minimum between takes, a towel hanging over the lens and front camera body, clear of the fan vents to reduce that little bit of heat conducted via the mount into the sensor area from a sun heated lens. It is not good to roast older lenses either as fractions may come off the lube to fog the glass over time and balsamic bonding of the compound elements may go yellow or begin to separate.

Indoors you are entirely at the mercy of the environment and the comfort that is affordable. That is where we have seen the highest temperatures reported by the camera.


That's just me spouting an opinion. Listen to the far better qualified and knowledged people here.

 

[Rob Ruffo]

I don't work for Red, but to save them the time, Jim and Deanan have already weighed-in on this ~18 months ago. Outcome was:
-upon firmware updates;
-upon extreme temperature changes;
-especially important for long exposures (not merely framerate changes) [Jim's add]

Also, black calibration is an additive process from the previous calibrations, in that if a pixel was stuck last time and has become unstuck this time, it will still be considered stuck. Conversely, a calibration reset will zero all previous calibration results and start fresh. If you do reset, make sure to perform a new calibration afterwards to give the camera at least 1 baseline test by which to operate.

Also, changing kelvin temps (e.g. tungsten to daylight) does not change anything with black calibration.

That was Red One advice.

 

[Rob Ruffo]

I said every shoot, not every shot. Huge difference. All I'm saying is set aside some time to black shade before you start rolling on a shoot in a new condition. Why is that so difficult to understand?

What's difficult is how to define "new conditions". New shutter? 6C temp difference? Humidity difference? Shooting outside, conditions by some measure are new every 20 minutes.

 

[Les C.]

That was Red One advice.

Do pixels get 'stuck' with MX? If so, how can one detect this?

Is the 'calibration reset' still necessary at times?

 

[Stephen Williams]

What's difficult is how to define "new conditions". New shutter? 6C temp difference? Humidity difference? Shooting outside, conditions by some measure are new every 20 minutes.

Huge major change, the people are blaming 'user error' to a camera fault, nothing new about that!

 

[Nick Gardner]

Hm... Am I the only one without huge blackshade issues on the Epic?

No. I only black shade when updating firmware (build) and have never had a problem ever. That's 4 years of Red one and so far on Epic. I've shot green screen, slow mo, low light etc, etc. no problems.

Nick