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Black Shading question for Red cameras


Saul Oliveira
 

Hello, 
just watched this: https://www.youtube.com/watch?time_continue=431&v=IM3epUuxxxg&feature=emb_logo

There they say that, for  Helium, Gemini & Monstro :
Doing a Black Shading at 25fps 180° ( 1/50sec)  you are ok in a range from 1/8sec to 1/8000sec. Should I understand this is doing just one Capture?
If yes:
1/8sec could be 4fps at 180° or 25fps at 360°. 1/8000sec could be 4000fps at 180° or 25fps at 1.1°. Even 200fps at 12° is just 1/6000. Even 7fps at 270° is just 1/9sec. Considering all this. Why would I want to do more than one Capture in manual mode o use  Auto mode ?

Best Regards
Saul Oliveira
First AC
Spain


tom@gleeson.net.au
 

Saul,

It’s a little confusing but if you are using any of the new sensors (Heluim, Gemini or Monstro) just do the single manual black shade and that will cover a huge range of exposures from 1/8th second to 1/8000th of a second. It doesn’t matter what combination of shutter speed or frames per second that gives you those integration times as long as you are in this range you are good. It’s only the Dragon sensor that requires the Auto black shade which will give you the multiple black shade captures at different exposures that the camera will then automatically select as needed.

It’s a rare event that you are likely to be outside the 1/8th to 1/8000th exposure and if you ever do you simply create a specific alternate black shade for that setting. As you point out more than one black shade for the new sensors is rarely required for most day to day work. 

IMHO if you did use the Auto black shade on the new sensors I don’t believe you would see any advantage and it will take an hour instead of a few minutes to do the auto over manual. I would just go with Red’s recommendations. Some on Reduser get their knickers in a knot over black shading but it really is simple. 

Personally I have a black shade at 42c for warmer Australian conditions that helps minimise fan noise and for about two months a year over winter I black shade again at 38c so the camera doesn’t take too long to warm up.

Sent from my combobulator
Tom Gleeson
SYDNEY DOP

On 5 Apr 2020, at 12:59, Saul Oliveira <oliveira_saul@...> wrote:

Hello, 
just watched this: https://www.youtube.com/watch?time_continue=431&v=IM3epUuxxxg&feature=emb_logo

There they say that, for  Helium, Gemini & Monstro :
Doing a Black Shading at 25fps 180° ( 1/50sec)  you are ok in a range from 1/8sec to 1/8000sec. Should I understand this is doing just one Capture?
If yes:
1/8sec could be 4fps at 180° or 25fps at 360°. 1/8000sec could be 4000fps at 180° or 25fps at 1.1°. Even 200fps at 12° is just 1/6000. Even 7fps at 270° is just 1/9sec. Considering all this. Why would I want to do more than one Capture in manual mode o use  Auto mode ?

Best Regards
Saul Oliveira
First AC
Spain


Saul Oliveira
 

I compilated all questions in one message:

Also related to this:

 

-They also say in the user manual that a new calibration is needed if the temperature change +/- 15ºC from the current selected calibration, but...
Is this range related to the Sensor Temperature or to the Core temperature (the two values we see in the camera display next to the "T"? or to the ambient temperatura?. I think I remember that the sensor temperature indication goes from green to yellow if it changes +/-4ºC from my current calibration.

 

-How much temperature change is needed for the T sensor temperature indicator to turn from Yellow to Red?

 

-The Quite fan mode: self adjust to maintain the lowest possible noise level while cooling the camera, but...
Coolin the camera means the fans try to reach the temperature of the selected Black Shading setting? or they forget about that and simple cool the camera to a save point of temperature for the unit?

Best Regards 
Saul Oliveira
First AC
Spain


Thomas Gleeson
 

Saul,

Yes the manual recommends a new calibration if the ambient air temperature is more than 15C or 30F different to the temperature you black shaded (BS) at so if you BS at 25C and the temperature went over 40C a new calibration is recommended BUT as long as the fans can keep the internal sensor at the BS operating temperature you are all good. The only downside is your fans may be getting loud. Same thing if the temperature dropped below 5C the camera may take longer to warm up but again it should still be all good once warm. There will be a point that extreme temperature at either end will overwhelm the cameras thermal management but I have never seen it and I live in Australia. As I said before a Summer and Winter black shade will cover any normal scenario. To be honest the Red DSMC 2 thermal management is way superior to the original DSCM 1 cameras. My nickname for my Epic was the “Hairdryer"

You are generally only interested in the sensor temperature as this is the relevant number for BS. I must admit I don’t know how many degrees change causes the T to change colour but remember yellow only indicates caution. You should be all good if the camera occasionally shows a yellow T. If the T is always yellow then it's time for a new calibration when you get 5 minutes. I have never noticed any quality drop with the yellow T lit up. If the T turns red then you should stop and sort it out. In my personal experience its only happened once when the camera was bolted to a horse driven chariot and some dirt got kicked into the fan stopping it. I suspect if your T is red then you may see an impact on the image? 

Saul I have not had much luck with the alternative fan modes on Red cameras. I have found Adaptive mode the best and this works 99% of the time. This is also the default mode for good reason. The few times it's been problematic are hot days shooting in small bathrooms and then rather using Quiet mode I will use Adaptive Preview Quiet Record as this mode allows the fans to spin up when not recording. Once finished I always go back to Adaptive as soon as I can. 

Saul I see your based in Spain so you should see summer conditions similar to Australia so I would recommend simply doing your black shade at a sensor temperature at say 43C and this will lower fan noise while only slightly increasing warm up time. If I can give you a tip I also do a black balance at a really high sensor temperature at 46C so on extreme hot days I just flick across to this calibration so the fan doesn’t work so hard. I generally don’t leave it on the 46C map as I am not sure this is good for the long term health of the sensor but I have no information on this.  


Many Thanks
Tom Gleeson
Sydney DOP



I compilated all questions in one message:

Also related to this:

 

-They also say in the user manual that a new calibration is needed if the temperature change +/- 15ºC from the current selected calibration, but...
Is this range related to the Sensor Temperature or to the Core temperature (the two values we see in the camera display next to the "T"? or to the ambient temperatura?. I think I remember that the sensor temperature indication goes from green to yellow if it changes +/-4ºC from my current calibration.

 

-How much temperature change is needed for the T sensor temperature indicator to turn from Yellow to Red?

 

-The Quite fan mode: self adjust to maintain the lowest possible noise level while cooling the camera, but...
Coolin the camera means the fans try to reach the temperature of the selected Black Shading setting? or they forget about that and simple cool the camera to a save point of temperature for the unit?

Best Regards 
Saul Oliveira
First AC
Spain
_._,_._,_


Jason Hall <jasecd@...>
 

Hi Saul,

Red says you only need to do another calibration if the ambient temperature varies by +-15º. I have a Gemini and at high frame rates (120fps @ 4K FF) and ISO's I feel like I have seen an improvement in noise by calibrating when there is a difference of only 7 or 8º. This is anecdotal and these are obviously settings where you would expect more noise but I certainly feel like you can get cleaner images if you calibrate more often when using these settings. At standard frame rates I haven't seen any issues and will only calibrate if, for instance, moving from cold night shoots to a warm studio.

Ordinarily I find the Gemini pretty stable and I stick to Red's recommendation above. I also generally leave the camera on 'Adaptive Preview Quiet Record' mode which tends to do a good job of managing the temperatures and fan volume. I think as you say 'Quiet Mode' means minimising fan speed regardless of temperature - the fans will then only kick in if the temperature gets too high.

--
Jason Hall
DP // Camera
Bristol // London


Saul Oliveira
 

The user manual is quite confusing in the subject, it say you should recalibrate:

After an extreme change in temperature (+/– 30°F or +/–15°C) from the current calibration map. 
Should we have to keep a thermometer at hand on set? and remember which the ambient temperature was when we calibrated?.They should relate this to the Sensor or Core Temperature, which is the data we have in the display. 

After an extreme change in exposure time (+/– 1/2 sec) from the current calibration map.

That gives me a much much widder range than what every college i consult is telling me. Normally they are calibrating for every 2/3stop or 1full stop in the exposure time, depending if shooting in darkness or daylight. 

If either the T or E in the CAL: T/E indicator is not green.
Apparently the T goes to yellow if the sensor temperature changes 4ºC, and goes to red at around a 8ºC change. Relating this to the first point, this one looks like a much narrow margin in temperature (i know one is ambient temperature and the other is sensor temperature but ...).

Also in the video link shown in my first message the exposure time margin stated there is way too much comparing to what the users i´m talking to are noting is necessary for absolute noise consistency. 

I think it´s too ambiguous information for an official professional digital camera. I´m not surprised this setting its been confusing to many professionals for too long. Also the fact that original Epic black shading menu page was much more rudimentary than now didn't help users to apply such an important setting in a convenient way for modern set conditions.  Luckily for us, users like us have made our part in understanding the setting and sharing this information so we can properly  understand it now. 

Best regards
Saul Oliveira
First AC 
Spain

Best Regards


David Fuller
 

1.) 30F degrees (15C) is a lot. You don’t need to carry a thermometer to know you’re experiencing that kind of temperature swing. But if you’re going from a studio at 70 degrees to a location that will be 20 degrees, you need to plan for it. Red is giving you the information to do that. 

2.) What yore hearing is the difference between the Red DSMC1 system and DSMC2. The recommendation you are reading in the manual applies to DSMC2. DSMC1 cameras do not have auto-balance, and are much more sensitive to chances in exposure time, but also calibrate faster. You need to read the manual for the camera you are actually using. It is common for users not to have current information and to assume that nothing has changed. 

3.) This is a way for the camera to let you know things are not optimal. Other than the warmup period, I have never seen that indicator go yellow or red unless I switched to an out-of-range shutter speed (DSMC1). It is useful in that it reminds you to load the proper black shade data. (Assuming that in prep, you saved the shading sets you would need.) 

It’s not really ambiguous at all. But as with many things in the Red ecosystem, there is a lot of bad information about something which is really quite simple, but is different for different generation cameras. 



David Fuller
207-415-1986
david@...


On Apr 11, 2020, at 10:11 AM, Saul Oliveira <oliveira_saul@...> wrote:

The user manual is quite confusing in the subject, it say you should recalibrate:

After an extreme change in temperature (+/– 30°F or +/–15°C) from the current calibration map. 
Should we have to keep a thermometer at hand on set? and remember which the ambient temperature was when we calibrated?.They should relate this to the Sensor or Core Temperature, which is the data we have in the display. 

After an extreme change in exposure time (+/– 1/2 sec) from the current calibration map.

That gives me a much much widder range than what every college i consult is telling me. Normally they are calibrating for every 2/3stop or 1full stop in the exposure time, depending if shooting in darkness or daylight. 

If either the T or E in the CAL: T/E indicator is not green.
Apparently the T goes to yellow if the sensor temperature changes 4ºC, and goes to red at around a 8ºC change. Relating this to the first point, this one looks like a much narrow margin in temperature (i know one is ambient temperature and the other is sensor temperature but ...).

Also in the video link shown in my first message the exposure time margin stated there is way too much comparing to what the users i´m talking to are noting is necessary for absolute noise consistency. 

I think it´s too ambiguous information for an official professional digital camera. I´m not surprised this setting its been confusing to many professionals for too long. Also the fact that original Epic black shading menu page was much more rudimentary than now didn't help users to apply such an important setting in a convenient way for modern set conditions.  Luckily for us, users like us have made our part in understanding the setting and sharing this information so we can properly  understand it now. 

Best regards
Saul Oliveira
First AC 
Spain

Best Regards


Saul Oliveira
 

Hi David,

I agree with you in point 1, they seem to be just telling us to shade when the temperature changes a lot. But it´s confusing for me to have such a general indication as "if temperature changes a lot" and also have a very narrow and exact one like "when the T indicator is not green" (which takes only 4ºC in the sensor in my experience last year with Helium).

For point 2: Helium user manual says a change in 1/2sec in exposure time is necessary to need a new shading, Epic build 3 manual stated 1/24sec, Epic build 5 manual already stated 1/2sec. But what i´m consulting with colleges is now, for the current sensors,and  I think they are all referring to DSMC2 camera manuals and to their experience with then, and still that is what people is telling me, 2/3 or 1 full stop of exposure change for real consistent noise. Maybe we can get along with less than that in some situations , but that is what is being followed here by some rental houses and DIT´s.
I´m not sure when E indicator is going to get yellow (I still calibrate for that 1stop change); but -if my math is ok- Is it really ok to manual calibrate for 1/50sec and be ok in a range from 25fps 360° to  25fps 1.1° like it is stated in the video link i indicated?. Seems to much for me. 

For 3.). Man I envy you!, I have experienced a quite different situation here last year with at least the 3 or 4 cameras we had in a series. Shooting on stage we have the fans in Adaptive Preview Quite Record for sync sound needs. The fans couln´t make it at an aceptable noise and we have to use a coupled manual operated mini fans that I turn up in stand by and down during the take, so the camera fans could stay at around 30% during the recording. If I forgot about the external fan at all, the camera started the take with fans at around 70%, which was to much noise there.  If T went yellow for repeated times during shots I recalibrated the sensor for a little bit higher temperature to help the situation. 
 
Best regards
Saul Oliveira
First AC 
Spain


David Fuller
 

For point 1) I think that’s simply because the ambient temp doesn’t directly affect sensor noise, only the temp of the sensor does, but the ambient temp affects the camera’s ability to maintain proper sensor temp.

For point 2) I’m confused by what you write in your first paragraph here. Do you mean to be saying exposure change? Or do you mean shutter speed change? (Exposure time.) A change in exposure will always change noise character because it changes the ratio of picture photons to noise. But only changes in exposure time affect noise levels in a way that is affected by black shading.

Yes, a shading is really OK for exposure times from 1/8 to 1/8000, regardless of how you arrive there. The video does mention an exception for very high frame rates, saying that it is wise to shade for those situations that run the camera to its max.

For point 3) Most of my experience is with DSMC1 cameras, but I have not had this experience. I don’t understand why the auxiliary fan is having such an impact in the studio. The camera’s fan should be increasing its flow whenever you are not recording, and that should have the desired cooling effect. Is the camera’s rigging blocking airflow? That said, if you are having consistent issues with this, Tom Gleeson’s suggestion of calibrating the camera for and running it at a higher temp (as you say you are doing) makes sense. I have, at times when I’ve done long interviews in hot environments, run the camera fans on manual and increased the fan speed by a couple of percent if the sensor temp seemed to be climbing, but I don’t ever remember needing to raise it past 37%. 


David Fuller
david@...
207-415-1986

On Apr 11, 2020, at 1:57 PM, Saul Oliveira <oliveira_saul@...> wrote:

Hi David,

I agree with you in point 1, they seem to be just telling us to shade when the temperature changes a lot. But it´s confusing for me to have such a general indication as "if temperature changes a lot" and also have a very narrow and exact one like "when the T indicator is not green" (which takes only 4ºC in the sensor in my experience last year with Helium).

For point 2: Helium user manual says a change in 1/2sec in exposure time is necessary to need a new shading, Epic build 3 manual stated 1/24sec, Epic build 5 manual already stated 1/2sec. But what i´m consulting with colleges is now, for the current sensors,and  I think they are all referring to DSMC2 camera manuals and to their experience with then, and still that is what people is telling me, 2/3 or 1 full stop of exposure change for real consistent noise. Maybe we can get along with less than that in some situations , but that is what is being followed here by some rental houses and DIT´s.
I´m not sure when E indicator is going to get yellow (I still calibrate for that 1stop change); but -if my math is ok- Is it really ok to manual calibrate for 1/50sec and be ok in a range from 25fps 360° to  25fps 1.1° like it is stated in the video link i indicated?. Seems to much for me. 

For 3.). Man I envy you!, I have experienced a quite different situation here last year with at least the 3 or 4 cameras we had in a series. Shooting on stage we have the fans in Adaptive Preview Quite Record for sync sound needs. The fans couln´t make it at an aceptable noise and we have to use a coupled manual operated mini fans that I turn up in stand by and down during the take, so the camera fans could stay at around 30% during the recording. If I forgot about the external fan at all, the camera started the take with fans at around 70%, which was to much noise there.  If T went yellow for repeated times during shots I recalibrated the sensor for a little bit higher temperature to help the situation. 
 
Best regards
Saul Oliveira
First AC 
Spain


Thomas Gleeson
 

Four Red cameras shooting simaltaneously in a quiet studio scenario sounds like trouble unless it has effective air conditioning. The sound of four fans could add up in high temperatures. Moving forward to today if I wanted multiple Red cameras working in tight spaces and I could not control ambient temperature I would not use DSMC1 or DSMC2 but go with the Ranger body type. Its larger body shell and improved thermals make fan noise a non issue even in high temps. Improved I/O and its larger body are also way more practical for drama as you can mount and hang more production “toys" on the cameras.
 
Many Thanks
Tom Gleeson
Sydney DOP



On 13 Apr 2020, at 1:25 am, David Fuller <david@...> wrote:

For point 1) I think that’s simply because the ambient temp doesn’t directly affect sensor noise, only the temp of the sensor does, but the ambient temp affects the camera’s ability to maintain proper sensor temp.

For point 2) I’m confused by what you write in your first paragraph here. Do you mean to be saying exposure change? Or do you mean shutter speed change? (Exposure time.) A change in exposure will always change noise character because it changes the ratio of picture photons to noise. But only changes in exposure time affect noise levels in a way that is affected by black shading.

Yes, a shading is really OK for exposure times from 1/8 to 1/8000, regardless of how you arrive there. The video does mention an exception for very high frame rates, saying that it is wise to shade for those situations that run the camera to its max.

For point 3) Most of my experience is with DSMC1 cameras, but I have not had this experience. I don’t understand why the auxiliary fan is having such an impact in the studio. The camera’s fan should be increasing its flow whenever you are not recording, and that should have the desired cooling effect. Is the camera’s rigging blocking airflow? That said, if you are having consistent issues with this, Tom Gleeson’s suggestion of calibrating the camera for and running it at a higher temp (as you say you are doing) makes sense. I have, at times when I’ve done long interviews in hot environments, run the camera fans on manual and increased the fan speed by a couple of percent if the sensor temp seemed to be climbing, but I don’t ever remember needing to raise it past 37%. 


David Fuller
207-415-1986

On Apr 11, 2020, at 1:57 PM, Saul Oliveira <oliveira_saul@...> wrote:

Hi David,

I agree with you in point 1, they seem to be just telling us to shade when the temperature changes a lot. But it´s confusing for me to have such a general indication as "if temperature changes a lot" and also have a very narrow and exact one like "when the T indicator is not green" (which takes only 4ºC in the sensor in my experience last year with Helium).

For point 2: Helium user manual says a change in 1/2sec in exposure time is necessary to need a new shading, Epic build 3 manual stated 1/24sec, Epic build 5 manual already stated 1/2sec. But what i´m consulting with colleges is now, for the current sensors,and  I think they are all referring to DSMC2 camera manuals and to their experience with then, and still that is what people is telling me, 2/3 or 1 full stop of exposure change for real consistent noise. Maybe we can get along with less than that in some situations , but that is what is being followed here by some rental houses and DIT´s.
I´m not sure when E indicator is going to get yellow (I still calibrate for that 1stop change); but -if my math is ok- Is it really ok to manual calibrate for 1/50sec and be ok in a range from 25fps 360° to  25fps 1.1° like it is stated in the video link i indicated?. Seems to much for me. 

For 3.). Man I envy you!, I have experienced a quite different situation here last year with at least the 3 or 4 cameras we had in a series. Shooting on stage we have the fans in Adaptive Preview Quite Record for sync sound needs. The fans couln´t make it at an aceptable noise and we have to use a coupled manual operated mini fans that I turn up in stand by and down during the take, so the camera fans could stay at around 30% during the recording. If I forgot about the external fan at all, the camera started the take with fans at around 70%, which was to much noise there.  If T went yellow for repeated times during shots I recalibrated the sensor for a little bit higher temperature to help the situation. 
 
Best regards
Saul Oliveira
First AC 
Spain


Saul Oliveira
 

Hi,

1) directly or indirectly it seems to affect it. But what i´m concern about is the way they explain it, the two affirmations relate to the same subject in a very different manner and I personally appreciate when user manuals are cristal clear and precise in these indications. 

2) Exposure time yes, sorry for that.

Yes, a shading is really OK for exposure times from 1/8 to 1/8000, regardless of how you arrive there. The video does mention an exception for very high frame rates, saying that it is wise to shade for those situations that run the camera to its max.
I will check with people here to see if anyone follows the red instructions to that extreme.

3)I must correct myself, we had the fans in Adaptive mode. We used Adaptive Preview Quite Record for some time but had heat problems in the sensor (during the take they slow down, the sensor rise its temp, and then the fans must rise to compensate, making too much noise for live sound); we also checked with manual mode to get down the temp during stand by by adjusting the fan speed quite high to start the take nice, but in small places and long takes the fans also rise to much during the take. Also checked making black shadings for higher temps to see and nothing seemed to find a nice balanced point between having the sensor temp inside the margin during takes and the fans al a low noise level.  that´s why we switched to the Adaptive mode for the internals and the help of the auxiliary external one. The auxiliary fan at hight speed in stand by allowed the sensor to stay in the lower part of the 4ºC "green" T indicator margin, while the camera fan stayed very low. Then while recording we turned low the auxiliary fan (but still helping to maintain the temp) so it doesn´t make noise, while the internal started very low and maybe rised to a nice point (aprox 25%) because the sensor was started the shot at the low part of his temperature margin. If not using that (sometimes I forgot to turn up the auxiliary fan between takes) the internal fans maintained the sensor at the correct temp (not in the lower part of the margin though) but in a noisy way.  That seemed to be the most successful combination of elements. 

Like Thomas said, going Ranger looks like the best choice in some situations I suppose. 

Best Regards
Saul Oliveira 
First AC 
Spain